Using Caffeine to Optimize Mental & Physical Performance

00:00:00.000 | - Welcome to the Huberman Lab Podcast,

00:00:02.260 | where we discuss science and science-based tools

00:00:04.900 | for everyday life.

00:00:05.900 | I'm Andrew Huberman,

00:00:10.300 | and I'm a professor of neurobiology and ophthalmology

00:00:13.260 | at Stanford School of Medicine.

00:00:15.180 | Today, we are discussing caffeine.

00:00:17.700 | Caffeine is one of the most widely used substances

00:00:20.020 | on the planet.

00:00:21.380 | Estimates are that more than 90% of adults

00:00:24.020 | and as many as 50% of kids,

00:00:26.660 | that is adolescents and teenagers,

00:00:28.420 | use caffeine on a daily basis.

00:00:31.340 | Caffeine is an amazing molecule.

00:00:33.560 | Most people are familiar with caffeine's ability

00:00:35.820 | to increase alertness and to reduce our feelings

00:00:38.980 | of sleepiness and fatigue, and indeed it does that.

00:00:42.260 | But what most people are not aware of

00:00:44.220 | is that caffeine acts as a strong reinforcer.

00:00:47.220 | What I mean by reinforcer is that when caffeine is present

00:00:50.440 | in a drink or food, and yes, indeed,

00:00:52.580 | caffeine is present in many foods, even unbeknownst to us,

00:00:57.380 | when it's present in drinks and foods,

00:00:59.380 | we actively come to like those foods and drinks more

00:01:03.620 | than if caffeine were not contained

00:01:05.780 | in those foods and drinks.

00:01:07.360 | So it reinforces our liking of particular foods and drinks,

00:01:11.020 | and indeed, it even reinforces our liking

00:01:13.900 | of the containers they are consumed from

00:01:16.560 | and the company we keep when we consume foods and drinks

00:01:20.580 | that contain caffeine.

00:01:22.200 | That is, caffeine is not just a stimulant,

00:01:24.900 | caffeine is a reinforcer, and it's a reinforcer

00:01:28.140 | that plays an active role in almost everybody's daily life.

00:01:32.180 | We can say that with confidence,

00:01:33.380 | because as I mentioned a moment ago,

00:01:35.020 | more than 90% of people are consuming caffeine,

00:01:37.500 | and most people think that they consume caffeine

00:01:39.780 | because it makes them feel more alert.

00:01:41.780 | But there are many reasons why you're consuming caffeine,

00:01:44.540 | and I'm not going to tell you

00:01:45.860 | that consuming caffeine isn't necessarily bad.

00:01:47.720 | In fact, today I'm going to tell you

00:01:48.980 | about many of the positive health benefits of caffeine,

00:01:52.020 | including neuroprotective effects,

00:01:54.660 | antidepressant effects,

00:01:56.060 | and certainly performance-enhancing effects,

00:01:58.340 | both for mental performance and for physical performance.

00:02:01.980 | Now, that said, there are certain situations

00:02:03.820 | in which you want to avoid caffeine,

00:02:05.280 | and there are certain people who might opt to avoid caffeine.

00:02:08.900 | That's especially the case when one thinks about caffeine

00:02:10.980 | not just as a stimulant, but as a reinforcer.

00:02:13.300 | In fact, caffeine is such a strong reinforcer

00:02:15.940 | that if even tiny amounts of caffeine are present

00:02:18.400 | in certain foods and drinks,

00:02:20.180 | you will very quickly come to prefer those foods and drinks

00:02:22.980 | over other choices, which can be a good thing or a bad thing,

00:02:26.460 | depending on what sorts of food and drink choices

00:02:28.480 | you're trying to make.

00:02:29.320 | So today I'm going to inform you

00:02:31.060 | about how caffeine works at a mechanistic level.

00:02:33.740 | I promise to do that with a minimum of nomenclature

00:02:36.340 | and such that even if you don't have a background in biology

00:02:39.300 | you will be able to digest that information easily.

00:02:41.820 | And then I'll tell you how to use caffeine to your advantage

00:02:44.740 | or conversely, how to avoid caffeine at certain times

00:02:48.780 | to your advantage.

00:02:49.900 | So today's episode will focus both on mechanisms

00:02:52.340 | and tools that is the use and leverage of caffeine

00:02:55.780 | to improve mental health, physical health, and performance.

00:02:58.660 | Before we go any further into today's discussion,

00:03:01.200 | I want to tell you about some recent results

00:03:03.480 | about a molecule that's found in certain caffeinated

00:03:06.820 | beverages and that has been proven to be very useful

00:03:10.220 | for both weight loss, mental performance

00:03:12.740 | and controlling blood sugar levels.

00:03:14.780 | And that's GLP-1 or glucagon-like peptide one.

00:03:18.440 | Glucagon-like peptide one is found in the brain and body.

00:03:22.680 | It acts both on the brain and body.

00:03:24.440 | It does many different things,

00:03:25.520 | but one of its primary effects that's been discovered

00:03:28.160 | is to reduce hunger and it does that two ways.

00:03:30.960 | It does that by activating certain neurons

00:03:33.300 | in your hypothalamus.

00:03:34.280 | So that's a brain region that controls hunger and satiety.

00:03:37.300 | It makes us feel full at the level of the brain.

00:03:39.800 | So it makes us feel sated that is,

00:03:41.720 | and it actually makes us feel full.

00:03:43.920 | Turns out that GLP-1 acts on certain receptors in the gut

00:03:47.280 | to make us feel as if we've ingested enough food.

00:03:50.320 | It doesn't necessarily make us feel

00:03:51.960 | as if our gut is distended, but it makes us feel full.

00:03:54.920 | That's really interesting because if you think about it,

00:03:56.760 | when we eat, our stomach fills up, obviously,

00:03:59.860 | and that information has to be communicated to the brain

00:04:02.720 | such that the brain can then send satiety signals

00:04:05.520 | that actually shut off our hunger.

00:04:07.240 | And believe it or not, the brain actually activates signals

00:04:09.660 | to reduce the desire to chew when our stomach is full.

00:04:13.160 | And GLP-1, as I mentioned, works on the brain

00:04:16.520 | to create these feelings of satiety as if we've had enough

00:04:19.840 | and to reduce our desire to eat more.

00:04:22.120 | And GLP-1 acts directly on the gut

00:04:24.240 | to give us a slight sense of fullness in the gut,

00:04:27.080 | which then is communicated to the brain.

00:04:28.640 | So really there are two parallel signals being sent

00:04:31.120 | when we have GLP-1 present in our system.

00:04:33.640 | Now, a little bit of relevant history on GLP-1,

00:04:35.720 | it was actually discovered in Gila monsters.

00:04:37.840 | These are these reptiles that can go long periods of time

00:04:41.320 | without eating, and a very clever scientist

00:04:43.000 | decided to study why it is that certain animals

00:04:46.120 | like Gila monsters can go a long period of time

00:04:49.540 | without ingesting anything.

00:04:50.640 | And it's because they produce very large amounts of GLP-1.

00:04:54.640 | They isolate the peptide from GLP-1,

00:04:56.520 | then they looked for the analogous peptide in humans,

00:05:00.540 | and it turns out that does exist.

00:05:02.160 | And as I mentioned, it's released in both brain and body

00:05:04.360 | to make you feel full and sated.

00:05:06.600 | Why am I telling you all this?

00:05:07.740 | Well, today we're going to talk about caffeine,

00:05:09.460 | and there's one particular caffeine source,

00:05:11.520 | which is yerba mate, and there's some other forms of teas,

00:05:14.840 | similar to yerba mate,

00:05:16.240 | that stimulate the release of GLP-1 significantly.

00:05:19.920 | There are also nowadays drugs,

00:05:21.540 | which are called analogs of GLP-1.

00:05:24.160 | So these are drugs that mimic or are identical

00:05:28.340 | to the kind of GLP-1 that you would make,

00:05:30.060 | and those drugs are proving to be very effective

00:05:31.840 | for the treatment of certain forms of diabetes

00:05:34.000 | and for the treatment of obesity,

00:05:35.820 | but they trigger enormous amounts

00:05:37.040 | of GLP-1 pathway activation.

00:05:38.960 | So those are extreme cases for people

00:05:40.880 | that are really struggling for weight loss,

00:05:42.480 | but the clinical trials and the data that are out there

00:05:45.280 | in the general population now are very, very promising

00:05:47.760 | for GLP-1 analogs.

00:05:49.920 | Yerba mate tea, provided it's not the smoked variety,

00:05:53.800 | and I mention that because a number of people

00:05:56.220 | have cued me to the fact that yerba mate teas

00:05:59.480 | come in smoked varieties and non-smoked varieties,

00:06:01.440 | and the smoked varieties are thought to perhaps

00:06:03.720 | be carcinogenic, that is pro-cancer causing.

00:06:07.040 | So I advise people to avoid smoked varieties

00:06:10.200 | of yerba mate tea,

00:06:11.600 | but yerba mate teas are known to stimulate

00:06:13.940 | significant amounts of GLP-1 release,

00:06:15.640 | and so they can be effective as a weight loss tool,

00:06:18.160 | mainly by blunting appetite.

00:06:20.480 | And again, they do that both at the level of the brain

00:06:23.260 | and at the level of the gut.

00:06:25.320 | Now, all of what I just told you has been known

00:06:27.060 | for some period of time,

00:06:28.560 | but there are a new set of findings that were just published

00:06:30.640 | in "Cell Reports Medicine," "Cell Press Journal,"

00:06:32.660 | "Excellent Journal," which indicate exactly how it is

00:06:36.720 | that GLP-1 stimulates both satiety

00:06:39.400 | and can trigger additional weight loss

00:06:42.040 | through other mechanisms.

00:06:43.340 | And I find the mechanism to be really interesting

00:06:45.520 | and actually really important,

00:06:47.000 | given some other topics we've covered

00:06:48.400 | on this podcast before.

00:06:49.680 | So the basic finding is that GLP-1,

00:06:52.920 | whether or not it's stimulated through the release

00:06:55.500 | of a analog drug that one is prescribed,

00:06:58.400 | or by drinking yerba mate tea, for instance,

00:07:00.760 | and stimulate release of your own

00:07:02.360 | so-called endogenous GLP-1,

00:07:04.320 | yes, it makes you feel more full

00:07:06.580 | at the level of brain and body,

00:07:07.720 | but it turns out it also stimulates thermogenesis.

00:07:11.020 | Now, thermogenesis is the active utilization

00:07:15.040 | of more metabolic energy.

00:07:16.760 | And fat cells, in particular,

00:07:19.320 | so-called beige and brown fat cells,

00:07:22.160 | are a potent source of thermogenic activity in your body.

00:07:25.320 | The basic background is that you have white adipose cells,

00:07:28.360 | so white fat cells, you have beige fat cells,

00:07:31.840 | and you have brown fat cells.

00:07:32.680 | And the beige and brown ones are fat cells

00:07:36.080 | that you actually want more of.

00:07:37.360 | They are not abundant under your skin.

00:07:38.960 | They're abundant really around your clavicles

00:07:40.540 | and your upper neck.

00:07:41.480 | They are the ones that generate heat,

00:07:43.200 | and the beige and brownness of them

00:07:45.800 | is actually the consequence

00:07:46.920 | of having a lot of mitochondria in those cells.

00:07:49.760 | When GLP-1 is elevated in your system,

00:07:51.960 | it turns out that it communicates to those white fat cells

00:07:55.680 | and helps convert them into beige and brown fat cells.

00:07:59.720 | That is, it takes fat cells

00:08:01.320 | that are not doing anything useful for you

00:08:02.960 | except being stored energy,

00:08:04.440 | and I think most people out there

00:08:05.480 | would like to have fewer of those white adipose cells.

00:08:08.720 | There are a few of you out there

00:08:09.560 | that actually need more of them

00:08:10.680 | that are too thin, too lean,

00:08:12.160 | but most people are suffering

00:08:13.600 | from having too many of these white adipose cells.

00:08:16.980 | Well, when you ingest Yerba Mate tea,

00:08:18.580 | or you were to take a GLP-1 analog

00:08:20.320 | or stimulate GLP-1 in any number of different ways,

00:08:23.520 | yes, you stimulate increased satiety,

00:08:25.480 | but you're also stimulating the conversion

00:08:28.440 | of these white fat cells into beige and brown fat cells,

00:08:33.180 | which makes you more thermogenic,

00:08:35.500 | and over time raises your basal metabolic rate,

00:08:38.800 | so you're burning more calories even at rest.

00:08:40.820 | It also makes you feel as if you're more comfortable

00:08:43.040 | in colder environments at rest.

00:08:45.900 | This is very much the same as the mechanism

00:08:49.300 | that's induced when you were to, say,

00:08:51.980 | take a cold shower or do regular ice baths

00:08:54.260 | or get into cold water regularly.

00:08:55.940 | That too stimulates the conversion of white fat cells

00:08:58.700 | to beige and brown fat cells.

00:09:00.560 | So I like these findings very much

00:09:01.860 | because they provide a mechanistic coherence.

00:09:04.860 | They provide, that is, a really nice story

00:09:07.300 | as to how something like GLP-1

00:09:09.140 | could be so effective for weight loss.

00:09:11.060 | Yes, on the one hand, GLP-1 is reducing appetite,

00:09:14.500 | and that of course will help people maintain or lose weight,

00:09:17.980 | but it's also increasing basal metabolic rate,

00:09:20.340 | and we now know how that's accomplished.

00:09:21.780 | It's likely accomplished at least through this one mechanism

00:09:25.120 | by the stimulation of conversion of these white fat cells,

00:09:28.740 | which don't do much for us except as energy storage units,

00:09:32.500 | to these metabolically mitochondrial-rich

00:09:35.140 | beige and brown fat cells,

00:09:36.820 | which you can think of as sort of the oil in the candle

00:09:39.060 | that allows your furnace, your metabolism to burn

00:09:42.460 | at a higher temperature and a higher rate.

00:09:44.580 | So that's the mechanism, and the basic tool takeaway

00:09:46.740 | is that if you are somebody who's interested

00:09:48.940 | in losing weight and you want to leverage the GLP-1 pathway,

00:09:52.980 | drinking a cup or two of Yerba Mate tea early in the day

00:09:56.940 | would be a great way to stimulate GLP-1 release.

00:10:00.480 | There are other ways to stimulate GLP-1 release.

00:10:02.380 | You can get it through certain forms of exercise,

00:10:04.220 | in particular fasted exercise.

00:10:05.720 | This is actually a vote in favor of fasted exercise.

00:10:08.120 | There's a debate as to whether or not fasted cardio

00:10:10.880 | burns more fat than non-fasted cardio,

00:10:12.660 | and the data basically say, no, it doesn't really matter,

00:10:15.860 | but that doesn't really take into account

00:10:17.980 | the longer arc of things like GLP-1 release,

00:10:20.420 | so that needs to be taken into consideration.

00:10:22.220 | So you could do fasted cardio,

00:10:23.500 | you could drink Yerba Mate tea,

00:10:25.320 | keeping in mind that Yerba Mate tea does contain caffeine.

00:10:27.700 | We'll talk more about the specific forms of stimulants,

00:10:30.520 | including caffeine that Mate has,

00:10:32.320 | but Mate would be a great way to stimulate GLP-1 release.

00:10:35.840 | And then of course, for those of you that are interested

00:10:37.800 | in more robust activation of GLP-1,

00:10:41.360 | then perhaps you might want to consider

00:10:42.880 | some of the new prescription GLP-1 analogs

00:10:45.040 | that are out there,

00:10:45.860 | but that's a more severe stimulus for GLP-1, of course.

00:10:49.160 | And for everybody, regardless of whether or not

00:10:50.780 | you're trying to lose weight, gain weight or maintain weight,

00:10:53.320 | I think we're going to be hearing a lot more

00:10:55.000 | about GLP-1 analogs and drinks and supplements

00:10:58.440 | and things of that sort that stimulate GLP-1

00:11:00.880 | in the very near future because it does appear

00:11:03.200 | to be a very important biological mechanism.

00:11:05.880 | Before we begin, I'd like to emphasize that this podcast

00:11:08.520 | is separate from my teaching and research roles at Stanford.

00:11:11.360 | It is, however, part of my desire and effort

00:11:13.440 | to bring zero cost to consumer information about science

00:11:16.000 | and science-related tools to the general public.

00:11:18.760 | In keeping with that theme,

00:11:19.880 | I'd like to thank the sponsors of today's podcast.

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00:15:22.580 | Let's talk about caffeine.

00:15:24.620 | So as I mentioned earlier, caffeine is consumed

00:15:26.620 | by basically most all adults every single day

00:15:30.540 | and consumed at very regular times each day.

00:15:34.660 | In fact, if you were to take a look at your caffeine intake

00:15:37.760 | or the caffeine intake of somebody close to you,

00:15:40.020 | what you would realize is that they don't do so well

00:15:43.380 | if their caffeine intake arrives even 10, 20

00:15:47.900 | or 30 minutes past their expected

00:15:50.640 | or usual intake of caffeine.

00:15:52.980 | That's pretty remarkable.

00:15:54.300 | And it brings to mind ideas

00:15:55.660 | that we are all quote unquote addicted to caffeine

00:15:58.520 | or that caffeine is somehow bad.

00:16:00.820 | I'm certainly not going to make the argument

00:16:02.440 | that caffeine is bad.

00:16:03.460 | First of all, I'm a regular caffeine user.

00:16:05.460 | I wouldn't call myself a caffeine abuser

00:16:07.120 | but I am a regular caffeine user.

00:16:08.980 | And caffeine is known to have certain health benefits.

00:16:11.960 | I listed off a few of them earlier

00:16:13.760 | but I'll mention those again now before going forward.

00:16:17.420 | Caffeine is known to have certain neuroprotective effects

00:16:21.300 | and that is because of its ability

00:16:23.100 | to increase neuromodulators such as dopamine

00:16:26.540 | but also other so-called catecholamines like norepinephrine.

00:16:29.640 | If you don't know what those names mean,

00:16:30.780 | these are molecules that increase levels of alertness,

00:16:33.420 | motivation and drive.

00:16:34.780 | And so then therefore not surprisingly,

00:16:36.640 | the large scale analysis of the relationship

00:16:39.960 | between depression and caffeine

00:16:41.660 | shows that provided people are not drinking so much caffeine

00:16:44.200 | that it makes them overly anxious,

00:16:46.740 | that regular intake of caffeine is inversely related

00:16:51.000 | to levels of depression.

00:16:52.380 | So it may have some antidepressant effects

00:16:54.600 | and those could be direct or indirect.

00:16:56.200 | What do I mean by that?

00:16:57.040 | Well, you can imagine that if people are ingesting caffeine

00:16:58.920 | and they are more motivated to do work

00:17:01.000 | and pursue quality social interactions,

00:17:03.280 | then the probability that they will have depression

00:17:05.980 | could be lower.

00:17:07.600 | It could also be that there are direct effects

00:17:09.620 | on the chemical systems of the brain

00:17:11.540 | that relate to mood and wellbeing

00:17:12.820 | that could offset depression.

00:17:13.920 | It is not clear whether or not the effects of caffeine

00:17:17.260 | in countering depression are direct or indirect.

00:17:19.700 | Nonetheless, there's a relationship there

00:17:21.500 | and it's an interesting and positive one

00:17:23.640 | or I should say negative correlation,

00:17:27.020 | positive effect overall on mood and wellbeing to be exact.

00:17:32.600 | Now it's also the case that caffeine can improve mental

00:17:36.120 | performance and physical performance.

00:17:37.640 | This has been demonstrated in tens of thousands of studies.

00:17:40.960 | I will review a few studies on this in particular today,

00:17:43.600 | but to just give you a sense of how caffeine works

00:17:45.880 | at the level of its timing and impact on mental performance

00:17:49.560 | and physical performance.

00:17:50.880 | When we ingest caffeine,

00:17:52.120 | provided that we don't have a lot of food in our stomach

00:17:56.000 | and that our blood sugar isn't particularly high,

00:17:58.280 | generally we experience an increase in alertness

00:18:00.880 | within about five minutes

00:18:02.160 | and that increase in focus and alertness peaks

00:18:04.800 | around 30 minutes after ingestion of caffeine

00:18:07.480 | and persists for as long as 60 minutes.

00:18:10.280 | Now this is assuming that one takes caffeine in pill form

00:18:13.160 | or drinks the entire caffeine drink

00:18:15.080 | within a short period of time.

00:18:16.720 | But a little bit later,

00:18:17.560 | I'll talk about how you can consume caffeine

00:18:20.240 | at regular intervals while doing mental work

00:18:22.880 | or physical work in a way that can further

00:18:24.760 | increase mental performance and physical performance.

00:18:27.680 | But let's just touch on what caffeine intake really does

00:18:30.280 | for mental performance and physical performance.

00:18:33.000 | Perhaps the most robust finding

00:18:34.880 | across all of the studies that I've examined

00:18:38.020 | is that caffeine reduces our reaction time.

00:18:41.240 | That is, it improves our reaction time.

00:18:43.560 | It doesn't make it longer, it makes it shorter.

00:18:45.220 | So for instance, in a laboratory study

00:18:46.960 | where people were asked to hit a lever

00:18:49.180 | every time they hear a tone,

00:18:51.240 | you can greatly reduce the time between the tone

00:18:54.480 | and the pressing of the lever

00:18:56.120 | if people ingest caffeine about 30 minutes

00:18:58.240 | before they do that task.

00:19:00.120 | Now that seems like a trivial task,

00:19:01.560 | but this is also seen in the domain of sports performance

00:19:04.840 | and even in cognitive performance

00:19:06.740 | where people have to arrive

00:19:08.400 | at a particular answer to a question.

00:19:10.700 | And the answer to that question has to be pulled

00:19:12.760 | from their memory banks within their brain,

00:19:14.940 | their hippocampus, for instance,

00:19:16.280 | a brain structure involved in memory.

00:19:18.560 | And if you are asking people, for instance,

00:19:21.000 | to remember the capitals of different states or cities

00:19:24.920 | or to remember certain historical facts,

00:19:28.020 | they will do that at a particular rate.

00:19:29.960 | But if they've ingested caffeine within the hour prior,

00:19:33.780 | their ability to recall that information

00:19:36.020 | is much, much better.

00:19:37.040 | They are faster and it does not appear

00:19:39.160 | that accuracy is reduced.

00:19:40.440 | In fact, in many cases, accuracy is enhanced.

00:19:43.440 | And that's because caffeine both works

00:19:45.840 | on the reaction time systems of the brain and body.

00:19:49.400 | I'll talk about the mechanisms for that in a little bit,

00:19:51.760 | but it also stimulates certain neurotransmitters

00:19:54.920 | and so-called neuromodulators within the brain and body

00:19:57.840 | that give the neural circuits in the brain

00:20:00.780 | that are associated with learning and memory

00:20:03.640 | a lower threshold to activation.

00:20:05.840 | What does that mean?

00:20:06.660 | That means that we are better able to access

00:20:09.600 | the brain circuitry involved in learning and memory

00:20:12.300 | when we have a certain amount of caffeine

00:20:14.040 | circulating in our system.

00:20:15.360 | So this makes caffeine

00:20:16.280 | an incredible performance-enhancing compound.

00:20:19.420 | And I could give you tens of thousands

00:20:20.920 | of examples of this in humans.

00:20:23.400 | But before I do that, I want to just touch on

00:20:26.540 | what we know about the existence of caffeine in nature

00:20:30.020 | and what the existence of caffeine in nature

00:20:32.460 | and its effects on other animals

00:20:34.180 | tells us about what caffeine does in humans.

00:20:36.540 | Because as I alluded to earlier,

00:20:39.780 | what caffeine is doing for us

00:20:41.420 | is not just making us more alert, improving our memory,

00:20:45.420 | improving our reaction time, and so on.

00:20:48.240 | It's actually acting as a powerful reinforcer of experience.

00:20:52.720 | And it's acting as not just a powerful reinforcer

00:20:55.560 | of the caffeine containing drink that we drink,

00:20:58.780 | but also the mug that it's contained in,

00:21:01.760 | plus the person that we might be sitting across from

00:21:04.160 | when we consume that caffeine, and so on and so forth.

00:21:07.260 | If it's a little bit hard for you to conceptualize

00:21:09.500 | what a reinforcer is and why I'm calling it a reinforcer,

00:21:13.640 | let me spell it out in three specific ways.

00:21:18.600 | We often hear about the word reward and we think,

00:21:21.280 | okay, if we do certain things and we like the outcome,

00:21:24.580 | then those certain things are rewarded, right?

00:21:26.840 | If we're doing something, we receive praise,

00:21:29.180 | the praise is the reward,

00:21:30.140 | and therefore we are more likely

00:21:31.600 | to do that thing in the future.

00:21:33.460 | In fact, a lot of parenting is like that

00:21:35.360 | and a lot of life is like that.

00:21:37.720 | However, when we hear the word reward,

00:21:40.040 | we often think about something that feels good to us.

00:21:42.780 | And certainly if we've worked hard and we get some praise,

00:21:45.260 | that's natural for the praise to feel good to us.

00:21:48.300 | Or for instance, if we work very hard

00:21:51.240 | and we get a certain outcome, a trophy, a financial outcome,

00:21:55.680 | a degree outcome, recognition, et cetera,

00:21:59.000 | all of those can act as rewards,

00:22:00.460 | but those are all conscious rewards.

00:22:02.920 | We are aware that they are happening.

00:22:05.360 | Reinforcers are a little bit different

00:22:07.320 | because the word reinforcement can apply

00:22:09.100 | to conscious rewards of the sort that I just described.

00:22:12.340 | But there are also many ways in which caffeine stimulates

00:22:14.520 | the release of chemicals in our body that act as reinforcers,

00:22:18.360 | but those reinforcers are subconscious.

00:22:21.060 | That is, we are not aware that they cause this preference

00:22:25.700 | for the activities that cause their release.

00:22:28.860 | So the study I'm about to describe beautifully, I believe,

00:22:33.160 | encapsulates how is it that humans came to consume caffeine

00:22:37.360 | and why caffeine exists in nature

00:22:39.680 | and the powerful effects of caffeine as a reinforcing agent,

00:22:43.280 | both in animals, insects, and in you and me.

00:22:46.560 | And the title of the paper is Caffeine and Floral Nectar

00:22:48.880 | Enhances a Pollinator's Memory of Reward.

00:22:51.840 | Keep in mind that caffeine is made from plants.

00:22:54.460 | Some of you will say, duh,

00:22:55.380 | but I think some of us don't realize that the reason why

00:22:58.700 | there is caffeine in coffee is because coffee comes

00:23:00.980 | from a plant, it's a coffee bean, certain teas,

00:23:03.720 | which of course are plants that people brew,

00:23:06.100 | caffeine is contained in those teas, such as yerba mate.

00:23:11.200 | Well, why would this bitter substance,

00:23:14.020 | because in fact, caffeine is quite bitter

00:23:15.880 | in high concentrations,

00:23:16.820 | why would this bitter substance be something

00:23:18.600 | that insects or animals would want to consume at all?

00:23:21.080 | It turns out that in most plants,

00:23:22.840 | caffeine is present in small enough quantities

00:23:26.640 | that insects and other animals,

00:23:28.280 | and in fact, we can't actually taste the caffeine.

00:23:30.480 | If I were to give you a little bit of pure caffeine,

00:23:32.840 | yes, it would be a stimulant for you,

00:23:35.160 | but you would say that it tasted awful.

00:23:37.540 | It's in a category of compounds

00:23:38.800 | that would strongly stimulate the bitter receptors

00:23:41.540 | on your tongue and would make you cringe and pucker

00:23:44.840 | and essentially walk away from whatever it is

00:23:47.380 | that contained that caffeine,

00:23:49.520 | and from the experience that contained that caffeine.

00:23:51.800 | Well, in nature, caffeine is present

00:23:53.620 | in very low concentrations or is masked by other flavors

00:23:58.620 | within flowers, beans, and plants.

00:24:02.420 | And what this paper really points to is that caffeine

00:24:05.980 | in nature is acting as a reinforcer for bees

00:24:09.520 | that are consuming different nectar.

00:24:11.580 | So the way that it works is that bees, of course,

00:24:13.700 | go from flower to flower,

00:24:15.820 | and they are consuming the nectar.

00:24:17.500 | They are bringing nectar and pollen back to the hive,

00:24:21.620 | and that provides critical nourishment for the bee colony.

00:24:26.620 | The bees are foraging in a way that includes information

00:24:31.280 | about color, in particular, ultraviolet color,

00:24:33.220 | things that we can't see, but they can see

00:24:34.720 | 'cause they have different photoreceptors than we do.

00:24:36.640 | And what this study shows is that plants and nectars

00:24:41.480 | that contain very small amounts of caffeine

00:24:45.440 | are the preferred sources of food for bees.

00:24:49.500 | And the study is beautiful because they were able to confirm

00:24:52.580 | that they could mask the caffeine taste,

00:24:54.480 | so they know that the bees are not preferring

00:24:56.240 | the taste of caffeine, but what they do is they pair caffeine

00:24:59.420 | with different food sources for the bees,

00:25:00.780 | then they remove the caffeine.

00:25:02.660 | And what they find is that the bees very strongly

00:25:04.920 | prefer flavors that contain caffeine,

00:25:08.360 | not because they could taste the caffeine,

00:25:10.980 | but rather for the way that those caffeine-containing flavors

00:25:14.620 | made the bees feel.

00:25:16.900 | So how do those caffeine-containing flavors

00:25:20.480 | make the bees feel?

00:25:21.960 | The same way that they make you and I feel,

00:25:23.680 | a little bit more alert and thereby able to do more work.

00:25:27.940 | For the bee, the more work is the consumption of more food,

00:25:32.200 | which then has a further reinforcing effect.

00:25:34.860 | So what we're really talking about here is the fact that,

00:25:37.240 | A, caffeine exists in nature, in plants.

00:25:40.760 | It exists in concentrations that are very low,

00:25:43.140 | so low in fact that they are not detectable

00:25:45.320 | to the taste receptors of insects,

00:25:47.280 | and in many cases to the taste receptors of humans.

00:25:50.040 | And of course, there can be high levels of caffeine

00:25:52.000 | in a plant, but if the plant also contains compounds

00:25:55.360 | that mask the flavor of caffeine,

00:25:57.160 | well then those plants are going to essentially

00:26:00.200 | be even stronger reinforcers for the flavor of the plant.

00:26:03.600 | So now we're talking about strong flavors

00:26:05.440 | plus strong neurostimulant effects of caffeine.

00:26:09.380 | And the most important point here is that

00:26:12.280 | all of these effects of caffeine are subconscious.

00:26:15.420 | It is not because the bee or you likes the taste of caffeine.

00:26:20.420 | In fact, most people, when they take their first sip

00:26:22.560 | of coffee, they find that it tastes bitter

00:26:24.660 | and kind of noxious, they don't like it.

00:26:27.320 | You may not even remember that

00:26:28.900 | because it happened so long ago,

00:26:30.280 | and because caffeine is such a strong reinforcer

00:26:32.380 | that very quickly you come to like the taste of coffee.

00:26:36.420 | You might even come to like the feeling

00:26:38.300 | of your mug in your hand.

00:26:40.440 | You might even come to like the smell of coffee

00:26:43.040 | and so on and so forth.

00:26:44.480 | And that's because caffeine stimulates the release

00:26:47.120 | of certain neurochemicals in the brain,

00:26:48.740 | in particular dopamine and acetylcholine,

00:26:51.560 | two neuromodulators that increase our focus

00:26:54.520 | and alertness and our feelings of wellbeing.

00:26:56.820 | A little bit later, I'll tell you that caffeine stimulates

00:26:59.560 | the release of dopamine in a way that's very much distinct

00:27:02.800 | from the classical dopamine pathway associated

00:27:05.200 | with addiction and reward.

00:27:06.440 | In fact, we can think of caffeine

00:27:07.640 | as having a somewhat privileged access to the reward systems.

00:27:12.080 | I'll give you a bit of a hint of where this is going.

00:27:14.200 | Caffeine stimulates the release of dopamine

00:27:16.660 | and acetylcholine, not within the classic

00:27:19.340 | so-called mesolimbic reward pathway.

00:27:21.000 | That's just fancy nerd speak

00:27:22.220 | for the reward pathways of the brain.

00:27:23.840 | They're associated with things like sex and food

00:27:26.000 | and drugs of abuse like cocaine and methamphetamine,

00:27:28.920 | but rather caffeine seems to stimulate the release

00:27:32.060 | of dopamine in the parts of the brain

00:27:33.680 | that are associated with alertness and cognition,

00:27:37.040 | meaning the forebrain.

00:27:38.760 | This is very important.

00:27:40.240 | We have multiple dopamine systems in the brain and body,

00:27:42.480 | and caffeine seems to stimulate dopamine directly

00:27:45.240 | within the components of the brain

00:27:47.160 | that are associated with clarity of thought and wellbeing,

00:27:51.080 | but more so clarity of thought.

00:27:53.400 | Now, I'm also talking about caffeine as a strong reinforcer

00:27:58.240 | in that it makes you feel good overall, and it does,

00:28:02.800 | and that suggests that it also taps

00:28:04.360 | into the more classic reward pathway,

00:28:06.180 | but it does that in a very interesting

00:28:07.840 | and frankly almost diabolical way.

00:28:10.540 | When we regularly ingest caffeine,

00:28:12.560 | it stimulates the increase in dopamine receptors

00:28:16.320 | at multiple sites throughout the brain,

00:28:18.120 | but in particular within the reward pathways of the brain.

00:28:20.560 | So not the areas of the brain that are associated

00:28:22.160 | with focus and clarity of thought and cognition.

00:28:24.540 | It does that, but it is also increasing the level

00:28:28.000 | of dopamine receptors in the reward pathway.

00:28:31.500 | And what that means is that for any dopamine

00:28:33.600 | that's released in response to a positive experience,

00:28:36.100 | social experience, or any number of the other things

00:28:38.840 | that can stimulate dopamine release,

00:28:41.320 | there are more receptors, more parking spots, if you will,

00:28:44.720 | for that dopamine to arrive at

00:28:46.600 | and to exert its increases in mood, increases in motivation,

00:28:51.600 | and overall feelings of drive and excitement.

00:28:55.560 | So there are four ways that caffeine works

00:28:57.120 | that we need to understand.

00:28:58.140 | First of all, caffeine acts as a reinforcing agent.

00:29:01.880 | It increases the probability that you will return to

00:29:05.260 | and engage in a certain activity

00:29:07.040 | or consume a certain beverage or food.

00:29:09.600 | Second of all, caffeine increases dopamine and acetylcholine,

00:29:14.360 | which are both neuromodulators in the forebrain,

00:29:17.000 | which helps us improve our ability to think,

00:29:20.280 | to modify our rule sets, that is to adjust our strategies

00:29:24.720 | for different social situations and mental demands

00:29:27.480 | and physical demands.

00:29:28.620 | And third, it increases the number and efficacy

00:29:33.080 | of dopamine receptors in the reward pathways of the brain.

00:29:36.980 | That is, it makes things that would feel pretty good

00:29:40.340 | feel even better.

00:29:42.420 | And fourth, caffeine acts as an antagonist to adenosine,

00:29:46.080 | which offsets the sleepiness that we would otherwise feel

00:29:49.440 | from the accumulation of adenosine that occurs

00:29:52.120 | as we are awake for more and more hours throughout the day.

00:29:54.600 | So let's talk first about caffeine as a reinforcing agent.

00:29:57.700 | Again, this was first most beautifully demonstrated

00:30:01.040 | in this study on honeybees where the bees prefer nectars

00:30:04.120 | that contain caffeine.

00:30:05.880 | And that all makes perfect sense in terms of the ecology

00:30:08.440 | of bees and flowers that contain nectar.

00:30:11.480 | There's an advantage, at least in terms of adaptation,

00:30:14.240 | that the flower benefits because of distribution

00:30:16.320 | of things from the flower, which is good for the flowers

00:30:19.000 | and the bees benefit because they're getting food.

00:30:21.480 | And so there's a kind of a symbiosis there.

00:30:24.240 | But with humans, we're consuming caffeine-containing

00:30:27.360 | beverages for our sake.

00:30:28.520 | I don't think we have it in mind,

00:30:30.000 | nor do the bees have it in mind, frankly,

00:30:31.740 | that we're trying to preserve the plants

00:30:33.160 | that provide the caffeine.

00:30:34.680 | I think we would all suffer, or I should say 90% of adults

00:30:38.680 | would suffer greatly if all the caffeine-containing coffee

00:30:41.640 | and tea plants were gone, certainly.

00:30:43.800 | But most of us are not consuming coffees and teas

00:30:46.820 | and caffeine-containing foods because we're thinking

00:30:48.940 | about the plants they come from

00:30:50.100 | and we want to help those plants.

00:30:51.140 | We're thinking about how we want to help ourselves.

00:30:53.240 | And yet the point of the reinforcing effects of caffeine

00:30:57.160 | are that they are largely subconscious.

00:30:59.720 | We are not aware of them.

00:31:01.440 | Now you might say, no, that's not true.

00:31:03.000 | When I drink caffeine, it makes me feel really good.

00:31:05.080 | So I'm aware that it makes me feel good.

00:31:08.100 | In order to illustrate how reinforcement really works,

00:31:11.480 | let me give you the counter example,

00:31:13.640 | which would be an aversive agent.

00:31:15.900 | So we have reinforcing agents and we have aversive agents.

00:31:18.680 | Let's say that there were compounds in nature

00:31:21.680 | that exist in plants that are aversive, and indeed they are.

00:31:25.080 | And let's say that these compounds were present

00:31:27.520 | at such low concentrations that you couldn't taste them.

00:31:30.920 | Let's say you wake up in the morning

00:31:32.060 | and you go to your refrigerator and you open it up

00:31:34.200 | and you are thirsty.

00:31:35.540 | And so you reach for a nice, you know,

00:31:37.880 | rich red containing beverage in a glass jar.

00:31:40.680 | Maybe it looks like cranberry juice

00:31:42.480 | or something of that sort,

00:31:43.600 | or even a nice clear glass of water.

00:31:46.280 | It looks like a jug of water, a glass of water,

00:31:48.120 | and you drink that.

00:31:49.700 | Tastes fine to you, maybe even tastes great to you.

00:31:52.800 | And then let's say about 30 minutes later,

00:31:54.960 | you feel a little queasy, you feel a little off,

00:31:57.240 | you feel like going back to sleep.

00:31:58.280 | You just don't feel very good.

00:31:59.880 | You don't know why, but your nervous system

00:32:05.160 | is a predictive machine and it has a process

00:32:08.360 | in which it back integrates, or I should say,

00:32:11.920 | integrates backwards into your immediate experience

00:32:14.940 | that preceded that not so good feeling.

00:32:17.000 | We can reliably say that there is a much lower probability

00:32:21.600 | that the next day when you wake up,

00:32:23.440 | that you would reach for that same beverage

00:32:27.000 | or for that same container even.

00:32:29.320 | And maybe if you're in a novel environment,

00:32:31.500 | maybe you're staying in an Airbnb or a hotel

00:32:33.440 | or something of that sort,

00:32:34.720 | you might even find that you don't really like the kitchen

00:32:37.680 | in which you consume that beverage in the first place.

00:32:40.520 | And then you don't know why.

00:32:42.300 | And unless you got very, very sick the day before,

00:32:45.640 | it's unlikely that you would have such a strong response

00:32:48.200 | that you would entirely avoid, for instance,

00:32:49.920 | water or glass jars containing liquids, et cetera.

00:32:53.040 | Let's say you went back to the refrigerator

00:32:55.520 | and you consumed beverage again,

00:32:57.080 | and you just didn't feel so well,

00:32:58.460 | you felt less good than you normally would.

00:33:01.040 | Well, even without any ability

00:33:04.960 | to taste what's in that beverage,

00:33:07.160 | and even without any understanding

00:33:08.940 | of what was happening to you at a conscious level,

00:33:11.960 | there is a very, very high probability

00:33:14.560 | that you will avoid drinking that particular beverage

00:33:17.480 | and certainly at that location

00:33:19.760 | and in the same volume in the subsequent days.

00:33:23.140 | That's just the way that aversive agents work.

00:33:24.980 | And they work by way of activating neurons in the gut

00:33:27.460 | that communicate with areas in the brain

00:33:29.380 | that give us this feeling of queasiness.

00:33:32.200 | And for some of you hearing this,

00:33:34.220 | that pathway and that association

00:33:36.940 | with times in which you felt queasy

00:33:38.980 | and as if you wanted to vomit is so powerful

00:33:43.460 | that you might even be feeling

00:33:44.740 | some of that symptomology now.

00:33:47.560 | For certain people, that's going to be increased salivation,

00:33:50.220 | which precedes vomiting.

00:33:51.700 | We know that there's a class of neurons in the brain

00:33:53.900 | related to an area called area postrema

00:33:55.980 | that actually stimulates vomiting.

00:33:57.500 | And if I keep talking about this,

00:33:58.580 | I'll probably feel like I want to vomit.

00:33:59.820 | So I'm going to move on from this in a moment.

00:34:01.540 | So when we ingest caffeine containing beverages and foods,

00:34:04.280 | it's the exact opposite scenario as to what I just described.

00:34:07.820 | Caffeine as a reinforcer makes us feel slightly better

00:34:12.780 | or a lot better in the immediate minutes

00:34:15.920 | and hours after we ingest it.

00:34:18.100 | So it's acting as a reinforcing agent,

00:34:20.460 | not just while you're under the effects of caffeine,

00:34:23.660 | but for the things that preceded the ingestion of caffeine,

00:34:26.700 | which is why you return again and again

00:34:28.860 | to caffeine containing beverages,

00:34:30.380 | such as coffee and tea,

00:34:31.900 | or maybe even foods that contain caffeine,

00:34:34.200 | even if the taste of those foods is not something

00:34:36.700 | that you would otherwise consider especially delicious.

00:34:40.280 | In fact, most people,

00:34:41.120 | when they take their first sip of coffee or tea

00:34:43.540 | or other caffeine containing beverage,

00:34:45.300 | they find it to be very bitter.

00:34:46.700 | And that's not because of the taste of caffeine.

00:34:49.060 | It's because of the taste of the beverage itself,

00:34:51.940 | independent of caffeine.

00:34:53.620 | However, when caffeine is present in there,

00:34:55.940 | they come to prefer that taste over most all tastes.

00:35:00.940 | In fact, they will, as I mentioned earlier,

00:35:02.860 | will invest a lot of financial resources

00:35:04.700 | and time and energy to make sure that they get that beverage.

00:35:07.340 | What they're trying to make sure

00:35:09.340 | is not that they get that taste,

00:35:11.420 | but that they get the caffeine.

00:35:13.440 | It is that positively reinforcing.

00:35:15.780 | And the taste therefore takes on new significance,

00:35:19.040 | new meaning, and we come to associate it as positive.

00:35:21.860 | And in fact, most of us, including myself,

00:35:24.140 | love the taste of espresso, love the taste of coffee,

00:35:26.500 | love the taste of yerba mate,

00:35:28.580 | even if the initial taste,

00:35:30.720 | the very first time that we consume that beverage

00:35:33.700 | was either neutral or negative.

00:35:35.860 | And that is all because of the reinforcing properties

00:35:38.380 | of caffeine.

00:35:39.220 | And then of course,

00:35:40.040 | there are the more direct actions of caffeine,

00:35:42.300 | that is the faster actions of caffeine.

00:35:44.560 | And just to list those off again very briefly

00:35:47.100 | so that you have them in mind going forward,

00:35:49.200 | caffeine also increases the release of dopamine

00:35:52.580 | and acetylcholine,

00:35:53.560 | both of which are neuromodulators in the forebrain,

00:35:56.040 | which increases clarity of thought

00:35:58.640 | and your ability to rule switch,

00:36:01.480 | your ability to move from one context to another

00:36:04.600 | and change and understand the rules of engagement,

00:36:07.700 | social engagement, physical engagement,

00:36:10.440 | mental engagement, and so forth.

00:36:12.260 | And as I mentioned before,

00:36:13.240 | caffeine also increases the number of dopamine receptors

00:36:16.740 | in the reward pathway,

00:36:18.200 | such that any good thing that happens to you,

00:36:20.720 | any positive experience that you have

00:36:23.140 | will have a more potent effect

00:36:25.100 | on your feelings of wellbeing.

00:36:27.140 | And last but certainly not least,

00:36:29.700 | caffeine acts as an adenosine antagonist.

00:36:32.860 | It reduces your feelings of lethargy and fatigue

00:36:37.340 | and your desire to sleep

00:36:38.920 | by parking in the receptors for adenosine

00:36:41.020 | and not allowing adenosine to have its pro sleepy,

00:36:44.780 | if you will, effects on your brain and body.

00:36:46.960 | I'd like to take a quick break

00:36:48.340 | and acknowledge one of our sponsors, Athletic Greens.

00:36:51.400 | Athletic Greens, now called AG1,

00:36:53.860 | is a vitamin mineral probiotic drink

00:36:56.220 | that covers all of your foundational nutritional needs.

00:36:59.120 | I've been taking Athletic Greens since 2012,

00:37:01.800 | so I'm delighted that they're sponsoring the podcast.

00:37:04.020 | The reason I started taking Athletic Greens

00:37:05.620 | and the reason I still take Athletic Greens

00:37:07.700 | once or usually twice a day

00:37:09.680 | is that it gets to be the probiotics

00:37:11.600 | that I need for gut health.

00:37:13.280 | Our gut is very important.

00:37:14.380 | It's populated by gut microbiota.

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00:37:18.700 | and basically all the biological systems of our body

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00:37:30.420 | In addition, Athletic Greens contains

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00:37:40.680 | you can go to athleticgreens.com/huberman,

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00:37:49.660 | on the plane, et cetera.

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00:38:01.340 | I'd like to just briefly talk about adenosine

00:38:03.620 | and some of its molecular features.

00:38:07.260 | And again, if you don't have a background in biology,

00:38:09.060 | don't worry, I promise to make this very clear to everyone.

00:38:12.060 | First of all, caffeine is what's called a methylxanthine.

00:38:15.900 | It's a plant alkaloid.

00:38:17.480 | That's why caffeine itself is very bitter.

00:38:19.860 | Again, if I were to give you just the tiniest little bit

00:38:21.700 | of pure caffeine,

00:38:23.300 | you would find it to be extremely aversive.

00:38:25.940 | And so these plants that have snuck

00:38:27.540 | small enough amounts of caffeine into them,

00:38:30.020 | or that have masked the flavor of caffeine

00:38:32.380 | with other flavors such that bees and humans

00:38:34.540 | want to consume them.

00:38:36.020 | While we don't know what plants think,

00:38:37.920 | it does seem very diabolical and very clever

00:38:40.660 | in that we are seeking out these caffeine-containing plants,

00:38:44.660 | beverages and foods,

00:38:46.460 | even though caffeine itself is this alkaloid

00:38:48.660 | is very, very bitter.

00:38:50.000 | Methylxanthine, that is caffeine,

00:38:54.920 | binds to adenosine receptors.

00:38:56.420 | And there are really two types of adenosine receptors.

00:38:58.500 | There are the so-called A1 receptors and the A2 receptors,

00:39:01.500 | and they're present in different parts of the brain and body

00:39:03.380 | at different levels.

00:39:05.100 | We don't have to get too far into receptor subtypes.

00:39:07.660 | More importantly to understand is that adenosine

00:39:10.960 | makes us feel tired because of the way

00:39:13.180 | that it taps into the ATP pathway.

00:39:16.900 | The ATP pathway is central to energy production

00:39:21.100 | and feelings of overall energy in our brain and body

00:39:23.720 | in all cells and organ systems.

00:39:26.500 | When caffeine binds to adenosine receptors,

00:39:29.500 | it prevents adenosine from breaking down certain components

00:39:33.240 | of the energy production pathway.

00:39:35.620 | And the net consequence of that is increased cyclic AMP.

00:39:39.180 | So basically when we ingest caffeine,

00:39:42.100 | we are biasing our system towards the pro-energetic aspects

00:39:46.260 | of these cellular pathways.

00:39:47.660 | Now it's really important to understand that in biology,

00:39:51.340 | even if you block a receptor or you prevent the activity

00:39:54.140 | of an enzyme, and at least in this case,

00:39:56.540 | you end up with more cyclic AMP, more energy,

00:39:59.460 | you're not really getting more energy.

00:40:01.340 | You're actually borrowing energy against an overall system

00:40:06.200 | that is frankly non-negotiable.

00:40:08.340 | What do I mean by that?

00:40:09.220 | Well, let's say that you were to wake up after six

00:40:12.660 | or eight hours of sleep and to drink a lot of caffeine

00:40:16.660 | and keep drinking caffeine throughout the day,

00:40:18.140 | throughout the day, blocking those adenosine receptors.

00:40:20.760 | Yes, you'll offset fatigue, you'll offset sleepiness

00:40:24.860 | because that adenosine simply can't function.

00:40:27.500 | But at the point where the caffeine becomes dislodged

00:40:31.000 | from the adenosine receptors, you will have a massive glut,

00:40:36.300 | a backlog of adenosine, and you will feel extra,

00:40:39.420 | extra sleepy.

00:40:40.700 | So really there's no way to create more energy

00:40:43.120 | in your system.

00:40:43.960 | Really what you're doing is you're changing the timing

00:40:46.640 | in which the sleepy signals and the more energetic signals

00:40:50.060 | are arriving.

00:40:51.300 | And this is really important to understand as the backdrop

00:40:54.400 | to the various tools that we're going to get into next

00:40:57.580 | in which you can use caffeine for enhancing mental

00:41:00.020 | performance and physical performance

00:41:01.460 | and other aspects of health.

00:41:03.380 | But it's very important to understand this concept

00:41:06.340 | that when you wake up in the morning provided

00:41:09.780 | that you slept well and enough the night before,

00:41:12.840 | your levels of adenosine will be about as low

00:41:15.800 | as they will ever be.

00:41:16.640 | Actually, in order to get your adenosine levels

00:41:19.400 | really bottomed out, you want to avoid caffeine

00:41:21.640 | in the first 90 to 120 minutes after waking.

00:41:23.700 | We'll talk about why that is because it turns out

00:41:25.560 | there's a way to completely clear adenosine

00:41:27.540 | out of your system in the hour or so after waking.

00:41:30.900 | But for most people, adenosine levels are going to be close

00:41:34.000 | to their lowest after a good night's sleep.

00:41:37.120 | But there's really no negotiating the accumulation

00:41:39.940 | of adenosine that's going to occur and going to bias you

00:41:43.960 | towards feeling more sleepy than you would otherwise

00:41:46.480 | that's going to occur throughout the day.

00:41:47.820 | There's really no way to eliminate adenosine.

00:41:49.740 | All you can really do is block its function.

00:41:51.500 | So it's sort of like borrowing energy against the fatigue

00:41:54.560 | that you will inevitably feel.

00:41:56.060 | Now, this actually has a very important

00:41:58.000 | socio-economical relevance.

00:42:00.920 | Before caffeine was regularly consumed by human beings,

00:42:06.240 | we were really slaves to the light-dark cycle.

00:42:10.000 | And this was especially true before the presence

00:42:12.400 | of artificial lighting.

00:42:13.720 | But even before the advent of artificial lighting,

00:42:16.560 | humans were largely constrained

00:42:18.840 | to the outside light-dark cycle.

00:42:21.360 | We need to be active during the day

00:42:22.640 | and working during the day,

00:42:23.760 | and we need to be asleep at night.

00:42:25.720 | Caffeine allows us to divorce ourselves

00:42:27.840 | from that circadian cycle.

00:42:29.200 | Circadian just means about 24 hour.

00:42:31.720 | Caffeine allows us to do that at least somewhat

00:42:34.520 | by way of increasing our alertness,

00:42:36.960 | that is spiking our alertness at various times

00:42:39.740 | throughout the day and even at night.

00:42:41.360 | This is how we can have shift workers, for instance,

00:42:43.300 | that can sleep during the day

00:42:44.760 | and then drink a strong cup of coffee at 8 p.m.

00:42:47.200 | and then work into the night.

00:42:48.640 | That ability completely transformed our society.

00:42:52.400 | Now, of course, the healthiest schedule,

00:42:54.560 | we know this with certainty,

00:42:55.680 | the healthiest schedule for brain and body

00:42:58.160 | is going to be alert during the daytime and asleep at night.

00:43:01.080 | There's no question about that.

00:43:02.120 | Shift workers run into all sorts of health problems.

00:43:04.640 | And thank you, shift workers,

00:43:05.680 | for doing the important work that you do.

00:43:06.960 | We need you, air traffic controllers, paramedics,

00:43:09.440 | firefighters, police officers, et cetera.

00:43:11.520 | But we know that there are serious health consequences,

00:43:15.340 | negative health consequences, that is, for shift workers.

00:43:18.120 | But for most people out there,

00:43:20.020 | about 95% of people follow a typical schedule

00:43:22.880 | where they're awake during the day and asleep at night.

00:43:24.960 | And yet it used to be,

00:43:25.800 | before the advent of caffeine-containing beverages,

00:43:28.320 | that if you were sleepy in the afternoon,

00:43:30.200 | you either had to take a nap or battle that sleepiness,

00:43:33.660 | that your activity rhythms and your sleep rhythms

00:43:36.600 | were governed by these circadian changes

00:43:40.360 | in availability of sunlight and when you slept.

00:43:45.360 | And you just didn't have the ability to ingest a beverage

00:43:48.460 | that would increase your levels of alertness

00:43:50.660 | because you block adenosine.

00:43:52.040 | So this is important to understand that nowadays,

00:43:54.460 | we certainly live in a time in which we use,

00:43:57.280 | in fact, 90% or more of adults

00:43:59.020 | and half or more of adolescents and teenagers,

00:44:02.400 | use caffeine as a way to negotiate with,

00:44:05.960 | to borrow against this natural pattern of adenosine

00:44:09.440 | making us sleepy.

00:44:11.000 | But again, you're just offsetting the effects of sleepiness

00:44:13.880 | that adenosine causes.

00:44:14.920 | You can't eliminate the adenosine entirely.

00:44:17.520 | The important point is that adenosine

00:44:19.400 | as a pro-sleepy molecule is a non-negotiable aspect

00:44:23.700 | of your biology.

00:44:24.960 | In fact, it's so non-negotiable that every 24 hours,

00:44:28.400 | you are going to release adenosine

00:44:30.400 | and you're going to release adenosine in direct proportion

00:44:33.140 | to how long you've been awake.

00:44:34.800 | So the longer you've been awake,

00:44:35.760 | the more adenosine circulating in your system.

00:44:37.680 | There are really only a handful of ways

00:44:39.480 | to completely clear out adenosine.

00:44:41.920 | The major one being to get sleep.

00:44:44.800 | The other is to take a short nap, which of course is sleep,

00:44:47.800 | but it's shallow sleep.

00:44:49.240 | Or non-sleep deep rest, so-called NSDR,

00:44:51.640 | has been shown to reduce levels of adenosine.

00:44:54.860 | And there are certain things

00:44:57.340 | such as viewing morning sunlight,

00:44:59.420 | which because of its effects on cortisol

00:45:01.580 | can quote unquote clear out adenosine.

00:45:03.740 | We'll talk about this in more detail in a few minutes.

00:45:06.220 | And there's also evidence that certain forms of exercise,

00:45:10.020 | provided that it's brief and intense,

00:45:12.460 | can also reduce adenosine, not just block its effects.

00:45:16.400 | Now that we've talked about some of the incredible mechanisms

00:45:18.740 | by which caffeine changes our experience of life

00:45:21.560 | increases alertness and mood, et cetera,

00:45:23.940 | I want to talk about the use of caffeine as a tool.

00:45:27.060 | Now caffeine is a very potent and useful tool

00:45:30.320 | for enhancing mental health, physical health,

00:45:32.380 | and performance.

00:45:33.540 | But there are certain considerations

00:45:35.020 | one has to keep in mind, in particular dose.

00:45:38.340 | Now, first off, not everybody will respond

00:45:41.140 | to the same dose of caffeine the same way,

00:45:43.540 | but we can reliably say that your body weight

00:45:46.940 | is a good measure by which you can estimate

00:45:50.420 | what a healthy, useful dose of caffeine would be.

00:45:54.420 | So for most people, ingesting one to three milligrams

00:45:57.740 | of caffeine per kilogram of body weight

00:46:00.860 | is going to be the range in which caffeine

00:46:03.100 | can have positive effects

00:46:04.900 | without making us feel overly anxious

00:46:08.020 | and give us that feeling that we're jumping out of our skin

00:46:11.360 | and turn the otherwise positive experience of caffeine

00:46:14.420 | into an aversive one.

00:46:15.780 | For those of you that aren't familiar with thinking

00:46:18.660 | in terms of kilograms and normally thinking pounds,

00:46:21.500 | I'll just quickly give you some general estimations

00:46:25.140 | that for instance, 100 kilograms equals 220 pounds.

00:46:29.700 | So for me, I weigh 100 kilograms.

00:46:31.940 | That means that one to three milligrams,

00:46:36.220 | again, milligrams, thousandths of a gram,

00:46:38.420 | one to three milligrams of caffeine

00:46:40.720 | per kilogram of body weight would mean for me,

00:46:43.220 | I could safely ingest 100 to 300 milligrams of caffeine

00:46:48.020 | in a single dose, in a single drink,

00:46:51.280 | if that's the way I'm consuming it,

00:46:52.900 | or pill form if that's the way that I'm consuming it.

00:46:55.580 | And it's very likely that that will be a tolerable dose.

00:46:58.740 | However, if you are not somebody that's accustomed

00:47:01.860 | to drinking caffeine on a regular basis,

00:47:04.220 | I suggest you start on the lower end

00:47:06.360 | of that one to three milligrams per kilogram

00:47:09.340 | of body weight range.

00:47:11.060 | So for instance, if you're somebody who weighs 50 kilograms,

00:47:13.780 | that's approximately 110 pounds,

00:47:16.660 | and you would be pretty comfortable ingesting

00:47:19.480 | somewhere between 50 and 150 milligrams of caffeine.

00:47:23.400 | So what I recommend is that people

00:47:24.860 | who are considering using caffeine as a tool

00:47:27.180 | or who are already ingesting caffeine,

00:47:29.780 | start to think about the dosage of caffeine

00:47:31.640 | that you are ingesting or plan to ingest

00:47:33.700 | and the timing in which you ingest that caffeine

00:47:36.580 | relative to certain tasks throughout your day,

00:47:39.620 | your waking and your sleep.

00:47:40.740 | And we'll talk about that in just a moment.

00:47:42.180 | But the first step for you is to figure out

00:47:44.860 | how much you weigh in kilograms,

00:47:46.900 | and then to go to that number of one to three milligrams

00:47:50.940 | of caffeine per kilogram of body weight.

00:47:53.160 | And that's a good range in which you might want

00:47:56.020 | to explore the use of caffeine in a single application,

00:48:00.120 | meaning in a single dose.

00:48:01.780 | Now, I do realize that some people out there

00:48:04.340 | are drinking coffee all day long

00:48:06.060 | or having coffee in the morning

00:48:07.380 | and then again in the afternoon.

00:48:09.620 | What I'm referring to here is the ingestion of caffeine

00:48:13.300 | in a single bout, right?

00:48:15.020 | One cup of coffee or two cups of coffee, for instance,

00:48:19.140 | to achieve that 100 to 300 milligram range

00:48:21.440 | if that's what's appropriate for your body weight.

00:48:23.300 | But to avoid any confusion,

00:48:25.020 | when I talk about dosage of caffeine,

00:48:26.880 | what I'm really talking about is not the total amount

00:48:29.340 | of caffeine ingested per day.

00:48:30.940 | I'm talking about the total amount of caffeine ingested

00:48:33.380 | in one sitting or setting, that is.

00:48:37.200 | And if you're somebody who's drinking caffeine

00:48:39.360 | multiple times throughout the day,

00:48:41.080 | you could imagine, for instance,

00:48:42.060 | let's say the appropriate dose for you

00:48:45.380 | in order to get an enhancement in mental performance

00:48:48.140 | or physical performance is 200 milligrams.

00:48:50.700 | And you are somebody who's doing some work in the morning

00:48:52.880 | and you want to have that lift in the morning

00:48:54.380 | to be able to focus better.

00:48:55.840 | And you're doing some physical exercise in the afternoon

00:48:57.920 | or vice versa, that you would ingest 200 milligrams

00:49:01.360 | of caffeine at two separate times per day,

00:49:03.900 | separated by about four hours.

00:49:05.940 | Now, you don't have to separate them.

00:49:07.100 | You could put them two hours apart, for instance.

00:49:10.320 | But we'll talk about half-life of caffeine and so forth.

00:49:13.380 | Just keep in mind that if you're ingesting 200 milligrams

00:49:16.280 | of caffeine, and that's the appropriate dose for you

00:49:18.960 | based on your body weight, and then you are ingesting

00:49:21.280 | another 200 milligrams of caffeine an hour later,

00:49:23.760 | you are effectively ingesting approximately 400 milligrams

00:49:27.580 | of caffeine, which is going to start exceeding the dose

00:49:30.740 | in which you can normally tolerate

00:49:32.540 | without feeling anxious and jittery.

00:49:34.660 | With all of that said, there is a range of tolerance

00:49:37.620 | for caffeine that's based on two things.

00:49:39.180 | One is a preexisting disposition.

00:49:41.740 | That is whether or not your genetics and nervous system

00:49:44.080 | and the backdrop of your life,

00:49:45.120 | how much stress you're experiencing,

00:49:46.620 | tends to make you feel more anxious and alert and jittery

00:49:49.460 | before you ingest any caffeine.

00:49:51.220 | And the other is how so-called caffeine adapted you are.

00:49:54.660 | We often hear about tolerance.

00:49:56.140 | Tolerance means something very specific.

00:49:57.740 | It's the ability to ingest more and more of something

00:50:00.800 | with a plateau that is a no increase

00:50:05.060 | or an actual reduction in the effectiveness of that thing.

00:50:07.980 | But here, we're not really talking

00:50:09.420 | about tolerance to caffeine.

00:50:10.600 | What we're talking about is being caffeine adapted.

00:50:12.740 | A simple way to understand whether or not

00:50:14.540 | you're caffeine adapted or not is that if you drink caffeine

00:50:17.980 | and it tends to increase your heart rate

00:50:20.060 | and make you feel more alert and a bit more anxious,

00:50:22.780 | then chances are you are not caffeine adapted,

00:50:25.000 | provided the amount of caffeine

00:50:26.180 | is within the healthy range for you, that is,

00:50:28.580 | the ranges we talked about a moment ago.

00:50:30.580 | However, if you're somebody who drinks caffeine

00:50:32.380 | and you actually feel alert and relaxed,

00:50:34.940 | chances are you are caffeine adapted.

00:50:37.340 | And so at various times during today's episode,

00:50:39.420 | I'll talk about people who are caffeine adapted

00:50:41.100 | and people who are not caffeine adapted.

00:50:43.180 | We'll talk about the use of caffeine every other day.

00:50:45.640 | I know a few habitual caffeine drinkers, including myself,

00:50:48.460 | just the simple mention of that probably sounds aversive,

00:50:52.580 | but there is actually great utility

00:50:54.580 | to using caffeine every other day as opposed to every day.

00:50:57.680 | But just keep in mind that some people will drink caffeine

00:51:00.280 | and not get much of a lift from it at all.

00:51:02.740 | Other people will drink caffeine

00:51:03.980 | and they will feel extremely anxious,

00:51:05.800 | even at dosages far lower than that one to three milligrams

00:51:09.860 | per kilogram of body weight range

00:51:12.560 | that I described a moment ago.

00:51:14.400 | So you have to take into account individual differences.

00:51:17.260 | That said, one to three milligrams of caffeine

00:51:19.320 | per kilogram of body weight for a given sitting,

00:51:22.960 | for your morning coffee or your morning Yerba Mate tea

00:51:26.580 | is a good range from which to start.

00:51:28.420 | And I do encourage you to go online

00:51:30.720 | and look up the various beverages and foods

00:51:32.980 | that you might be eating that contain caffeine

00:51:35.740 | For instance, some people are surprised to discover

00:51:39.500 | that the coffee that they get

00:51:41.020 | from some of the more standard popular vendors out there,

00:51:44.340 | the small coffee or the median coffee, for instance,

00:51:48.260 | can contain as much as 400 to 600 milligrams of caffeine.

00:51:52.340 | And that the large coffee that is often sold

00:51:55.060 | at those commercial vendors can contain as much as one gram,

00:51:58.100 | 1000 milligrams of caffeine.

00:52:00.820 | Now you may be adapted to that

00:52:02.260 | such that it doesn't make you feel anxious,

00:52:04.340 | but if you wonder why you feel irritable

00:52:06.820 | and you get a headache when you don't get that caffeine

00:52:10.020 | or that amount of caffeine at precisely the time

00:52:14.120 | that you're used to getting it each day,

00:52:15.880 | that's because you are consuming quite large quantities

00:52:19.820 | of caffeine on a regular basis.

00:52:21.740 | So I do recommend whether or not you drink soda

00:52:23.940 | or coffee or tea that you figure out the source of that.

00:52:27.660 | Okay, so figure out what vendor you purchase it from,

00:52:30.940 | what kind of coffee and go online

00:52:32.500 | and spend a little bit of time

00:52:33.860 | because the information is out there

00:52:35.140 | to discover what levels of caffeine

00:52:37.960 | you're actually ingesting.

00:52:39.560 | Now, if you happen to be ingesting

00:52:41.060 | more than one to three milligrams per kilogram

00:52:43.040 | of body weight of caffeine, that's not necessarily bad.

00:52:46.380 | However, you do want to be careful

00:52:48.700 | about ingesting very high levels of caffeine

00:52:50.740 | over long periods of time in your life

00:52:53.940 | because there can be issues that start to arise,

00:52:56.460 | in particular, a bias towards higher levels of anxiety

00:53:00.020 | and depletion of certain electrolytes

00:53:02.640 | because caffeine is a diuretic,

00:53:03.980 | can cause you to lose sodium and other things of that sort.

00:53:06.900 | And also just from simply a dependent standpoint,

00:53:10.700 | it does appear that if you ingest high levels of caffeine,

00:53:14.940 | that is exceeding the dosages

00:53:16.500 | that normally you could get away with

00:53:18.420 | and get just as much mental enhancing

00:53:20.720 | and physical enhancing benefits,

00:53:23.080 | that you can cause some disruption to the microvasculature,

00:53:27.080 | you can bias yourself towards headaches, anxiety attacks,

00:53:29.900 | and you can become actually quite irritable

00:53:31.860 | when you're not getting those higher levels of caffeine.

00:53:34.100 | So I do encourage you to figure out

00:53:35.760 | not just what an appropriate caffeine dosage would be for you

00:53:38.940 | but also how much caffeine you might already be ingesting.

00:53:42.000 | The first tool I'd like to talk about

00:53:43.580 | is one that I've mentioned before

00:53:45.440 | on this podcast several times.

00:53:47.760 | And it's something that if you haven't heard of

00:53:50.780 | will be very useful to you.

00:53:51.980 | And if you have heard this tool before,

00:53:54.240 | I'm going to add some additional features

00:53:56.020 | to the description of this tool

00:53:57.540 | that should make this worthwhile for you as well.

00:53:59.700 | And that is to delay your caffeine intake

00:54:03.460 | to 90 to 120 minutes after waking up on most days.

00:54:08.460 | And I'll be very clear as to days

00:54:10.980 | in which you might want to ingest caffeine

00:54:13.700 | more closely to when you wake up.

00:54:15.660 | Why would you want to delay your caffeine intake

00:54:17.980 | to 90 to 120 minutes after waking?

00:54:22.000 | The answer to that is very simple.

00:54:23.700 | Many people wake up in the morning,

00:54:26.580 | they drink caffeine within 10, 20, 30,

00:54:29.700 | sometimes within two minutes of waking,

00:54:32.520 | and they feel more alert naturally.

00:54:34.660 | That makes sense because of the effects of caffeine

00:54:36.780 | in blocking the effects of adenosine

00:54:38.620 | that I talked about earlier

00:54:39.740 | and its effects on other neurotransmitter systems.

00:54:42.800 | But then what they find is that in the early afternoon,

00:54:46.060 | in particular after lunch,

00:54:48.060 | they experience a dramatic dip

00:54:50.180 | in their overall levels of energy,

00:54:51.580 | the so-called afternoon crash.

00:54:54.060 | And in most cases, the way they respond to that

00:54:56.740 | is to ingest more caffeine,

00:54:58.380 | which indeed can increase their levels

00:55:00.860 | of mood and alertness.

00:55:02.820 | However, as we'll soon talk about,

00:55:05.040 | there is a problem with ingesting caffeine in the afternoon

00:55:08.220 | if it falls within eight or 10 or dare I even say 12 hours

00:55:13.220 | of going to sleep.

00:55:14.340 | And that is the caffeine ingested in the afternoon

00:55:16.900 | for most everybody,

00:55:19.820 | let's say for 95 plus percent of people disrupts

00:55:24.100 | the architecture and quality of their nighttime sleep.

00:55:27.080 | And I should say that it doesn't necessarily impact

00:55:29.420 | their ability to fall asleep

00:55:30.740 | and maybe even sleep through the night,

00:55:32.660 | but that the depth and quality of that sleep is disrupted

00:55:36.300 | by consuming caffeine in the afternoon.

00:55:38.260 | A little bit later, I'll talk about how you can offset

00:55:40.340 | some of those negative effects

00:55:41.760 | if you absolutely require caffeine in the afternoon.

00:55:44.840 | But there's a huge advantage

00:55:46.300 | to restricting your caffeine intake

00:55:47.760 | to the early part of your day,

00:55:49.260 | but not consuming caffeine

00:55:51.160 | within the first 90 to 120 minutes after waking.

00:55:54.240 | In fact, many people find that if they delay

00:55:57.820 | their caffeine intake to 90 to 120 minutes after waking up,

00:56:02.060 | that they feel more alert in the morning

00:56:04.700 | and they completely avoid that afternoon crash.

00:56:07.760 | Now that said, many people including myself

00:56:09.820 | do need a short nap or non-sleep deep rest

00:56:13.980 | or other form of relaxation

00:56:15.500 | for 10 to 30 minutes in the afternoon.

00:56:17.260 | That is natural and healthy.

00:56:19.220 | I'm not referring to the need for that

00:56:22.220 | when I refer to the so-called afternoon crash.

00:56:24.700 | What I'm talking about in the afternoon crash

00:56:25.980 | is a inability to recover energy and focus

00:56:29.780 | and a need to consume more caffeine

00:56:31.660 | just to make it through the afternoon.

00:56:34.260 | By delaying caffeine intake to 90 to 120 minutes

00:56:37.880 | after waking, there are a couple of things

00:56:39.980 | that are accomplished.

00:56:40.820 | First of all, you offset that afternoon crash,

00:56:43.460 | and this is an effect that many people experience

00:56:45.260 | the very first time they start delaying their caffeine intake

00:56:47.900 | to 90 to 120 minutes after waking.

00:56:50.540 | And the reason this works so well is the following.

00:56:53.780 | As I mentioned earlier, adenosine is a molecule

00:56:56.260 | that builds up the longer that we are awake.

00:56:58.340 | It is a molecule that is reduced

00:57:00.980 | or cleared from our system by sleep.

00:57:03.980 | So when we emerge from sleep,

00:57:05.660 | regardless of how long we've slept,

00:57:08.040 | our adenosine levels are lower than they were

00:57:10.940 | when we went to sleep the previous night.

00:57:13.860 | If you slept well enough and long enough,

00:57:17.720 | those adenosine levels can be very, very low,

00:57:20.800 | but they are never completely zero.

00:57:23.580 | When you wake up in the morning,

00:57:24.560 | even if you're one of these people that springs out of bed

00:57:26.980 | and is ready to attack the day,

00:57:28.660 | and here I'm certainly not describing myself,

00:57:31.140 | I'm not one of those people, I tend to wake fairly slowly.

00:57:35.000 | But if you're one of those spring up and attack the day,

00:57:37.820 | or you're one of the people who moves more slowly

00:57:41.300 | into your day, regardless,

00:57:43.960 | there's still some residual adenosine in your system.

00:57:46.380 | And this is particularly the case

00:57:48.000 | if you did not get enough sleep

00:57:49.500 | or enough depth of sleep the night before,

00:57:51.880 | the correct ratios of slow wave sleep

00:57:53.800 | and rapid eye movement sleep.

00:57:54.960 | And for those of you interested in optimizing sleep,

00:57:56.940 | I'll just refer you to our Master Your Sleep episode

00:57:59.860 | of the Huberman Lab Podcast,

00:58:01.180 | the Perfect Your Sleep episode of the Huberman Lab Podcast.

00:58:04.100 | And we have a toolkit for sleep, all of which are available,

00:58:06.320 | zero cost, timestamped, et cetera, at HubermanLab.com.

00:58:09.320 | You wake up in the morning

00:58:12.480 | and your adenosine levels are low,

00:58:15.400 | but they're not zero.

00:58:16.960 | And if you didn't sleep that well

00:58:18.440 | or deeply enough the night before,

00:58:20.820 | you're going to have more adenosine in your system.

00:58:23.320 | You might think the logical thing to do

00:58:25.920 | is therefore to drink caffeine

00:58:27.180 | and to block the adenosine that's there.

00:58:29.460 | But what happens if you do that is there's an accumulation,

00:58:32.360 | a sort of glut of adenosine that hangs around.

00:58:35.780 | And then in the afternoon,

00:58:36.960 | when the effects of that caffeine start to wear off,

00:58:39.480 | you will experience the so-called afternoon crash.

00:58:42.700 | As I mentioned earlier,

00:58:43.940 | there is a way to clear out the adenosine that's present

00:58:47.760 | when you wake up in the morning

00:58:49.660 | and to clear it out essentially completely

00:58:52.940 | without just blocking its receptors

00:58:55.280 | and letting it accumulate or hang around.

00:58:57.940 | And the way to do that

00:58:59.300 | is to deliberately spike your cortisol.

00:59:02.020 | Now, many of you have heard of cortisol,

00:59:03.900 | the so-called stress hormone, as a bad thing.

00:59:06.500 | And indeed chronically elevated cortisol is a bad thing.

00:59:09.380 | It depletes your immune system.

00:59:11.140 | It's bad for psychosocial effects.

00:59:13.660 | It tends to make us feel anxious and on and on.

00:59:16.640 | But cortisol itself is not bad.

00:59:18.420 | Cortisol is wonderful.

00:59:19.640 | Cortisol enhances the efficiency of the immune system.

00:59:23.620 | It makes us alert and focus.

00:59:25.300 | It stimulates our metabolism.

00:59:26.580 | It does a huge number of positive things

00:59:29.440 | provided that it is released in a circadian fashion,

00:59:33.620 | that is at the appropriate times every 24 hours,

00:59:36.340 | and that it tends to peak very close to waking.

00:59:38.740 | In fact, one of the reasons you wake up in the morning,

00:59:41.020 | assuming that you weren't woken up by some noise

00:59:43.260 | or sleeping in an environment that's too warm, et cetera,

00:59:46.740 | is that your cortisol levels start to rise.

00:59:49.100 | And shortly after waking,

00:59:50.400 | your cortisol levels will start to reach their peak.

00:59:52.900 | And when I refer to a cortisol pulse,

00:59:55.220 | that's just, I mean, biology nerd speak

00:59:57.520 | for a rise and peak in cortisol.

01:00:01.760 | You want that cortisol pulse to occur

01:00:04.140 | early in the day close to waking.

01:00:06.120 | And you want that for a couple of reasons.

01:00:07.620 | First of all, if you don't restrict that cortisol pulse

01:00:10.720 | to early in the day,

01:00:12.180 | it will tend to bleed into the later parts of the day.

01:00:15.000 | And actually a late shifted cortisol peak

01:00:17.860 | is one of the hallmark signatures of depression,

01:00:20.380 | low level depression and serious depression.

01:00:22.140 | And it can start to disrupt sleep

01:00:23.620 | and certainly can disrupt mood metabolism

01:00:26.360 | and your immune system.

01:00:28.020 | So you want that cortisol peak early in the day.

01:00:29.860 | How do you ensure that that happens?

01:00:31.460 | Well, you wake up in the morning

01:00:32.640 | and whether or not you're a bounce out of bed type

01:00:34.820 | or you're a more groggy,

01:00:36.220 | you know, kind of wade slowly into the day type like I am,

01:00:39.500 | you wake up and you don't ingest caffeine.

01:00:44.020 | Fine and in fact beneficial to hydrate

01:00:46.800 | with water and electrolytes.

01:00:48.680 | Terrific, in fact, I would say necessary

01:00:53.660 | to get bright light in your eyes, ideally from sunlight.

01:00:55.980 | I've talked about this many, many times before

01:00:57.460 | on the podcast.

01:00:58.300 | If you wake up before the sun comes out,

01:00:59.900 | then turn on bright artificial lights,

01:01:01.580 | but then certainly once the sun is out

01:01:03.220 | and even on cloudy days, in fact,

01:01:05.240 | especially on cloudy days,

01:01:06.540 | get outside for anywhere from five to 20,

01:01:08.600 | maybe even 30 minutes, do some work outside,

01:01:10.760 | take your breakfast outside if you're a breakfast eater,

01:01:14.060 | get something done outside,

01:01:16.140 | even if it's just to get outside

01:01:17.520 | and get bright light in your eyes, why?

01:01:19.540 | Well, because it's been shown in studies on humans

01:01:23.300 | that getting bright light in your eyes

01:01:25.260 | in the first hour after waking

01:01:27.140 | or as soon as possible after waking

01:01:30.040 | increases the peak of that cortisol pulse by 50%, 5-0.

01:01:35.040 | And that cortisol pulse, yes, increases mood,

01:01:37.460 | yes, increases alertness,

01:01:38.620 | but it does one other very important thing,

01:01:40.860 | which is that through an indirect pathway,

01:01:43.940 | it can clear out any residual adenosine

01:01:46.940 | that might be present in your system

01:01:48.300 | when you wake up in the morning.

01:01:50.140 | Again, this is going to be especially important

01:01:51.720 | for those of you that are not getting as much sleep

01:01:53.760 | or as much quality sleep as you would like.

01:01:56.940 | It's going to be very important for you

01:01:58.500 | to get that morning bright light, ideally from sunlight,

01:02:01.220 | get that cortisol peak going.

01:02:02.780 | Other ways to increase that cortisol peak

01:02:04.520 | would be to do some physical activity.

01:02:06.600 | If you don't have time to do a full workout,

01:02:08.580 | well, then getting some movement,

01:02:11.640 | 10 minutes of skipping rope

01:02:12.720 | or even five minutes of skipping rope or jumping jacks

01:02:14.980 | or walking if that's all you have time for,

01:02:17.720 | ideally while getting the sunlight in your eyes,

01:02:19.880 | but that's going to zero out

01:02:21.440 | the adenosine present in your system.

01:02:23.600 | If however, you were to wake up

01:02:27.340 | and immediately drink caffeine,

01:02:29.580 | caffeine itself can stimulate the release of cortisol

01:02:32.660 | a little bit more than it would otherwise

01:02:35.500 | be present in your system,

01:02:37.120 | but by blocking those adenosine receptors

01:02:41.060 | and because of the indirect effects of caffeine

01:02:43.760 | on the cortisol system,

01:02:45.300 | you actually are reducing the clearance of adenosine

01:02:48.420 | that would otherwise occur.

01:02:50.300 | So I realize that's a mouthful, just to be very clear,

01:02:52.700 | if you wake up and you ingest caffeine right away,

01:02:55.400 | you're blocking the adenosine receptor,

01:02:56.960 | but you're not clearing it out.

01:02:58.120 | You're also preventing cortisol

01:03:00.480 | from having its normal increase in rise

01:03:03.440 | such that it can directly clear out adenosine

01:03:06.600 | because cortisol can clear out adenosine.

01:03:10.340 | And that's what you want.

01:03:11.380 | You want to be at maximum alertness and focus

01:03:14.080 | in your morning and throughout your day.

01:03:16.020 | And by delaying your caffeine

01:03:18.240 | to 90 to 120 minutes after waking,

01:03:20.820 | you set up your system

01:03:22.380 | so that you get that morning cortisol peak,

01:03:24.180 | ideally a peak that's even greater

01:03:25.920 | because you're getting your bright light viewing.

01:03:29.000 | And then when you ingest your caffeine

01:03:31.360 | 90 to 120 minutes after waking,

01:03:33.740 | not only will you be craving it just a little bit,

01:03:36.220 | but you will be drinking that caffeine

01:03:38.220 | on an already existing backdrop of increased alertness

01:03:42.860 | for two reasons.

01:03:43.700 | One is adenosine is zeroed out

01:03:47.720 | and your cortisol peak is higher.

01:03:50.020 | And so now when you ingest caffeine,

01:03:51.660 | you can actually ingest levels of caffeine

01:03:53.620 | that are a little more reasonable,

01:03:55.060 | that almost with certainty are going to fall

01:03:57.400 | in this one to three milligrams per kilogram dosage

01:04:00.900 | and will allow you to feel really alert

01:04:03.520 | and will carry that alertness well into the afternoon hours

01:04:07.340 | without the need to drink more caffeine

01:04:09.720 | and thereby will prevent you from drinking caffeine

01:04:13.020 | and disrupting your nighttime sleep.

01:04:15.020 | And of course, by getting better nighttime sleep,

01:04:17.280 | you're going to zero out your adenosine even more.

01:04:19.560 | So what I'm describing here are essentially two tools.

01:04:22.260 | I'm telling you to get morning sunlight

01:04:23.700 | and maybe some exercise in conjunction with that,

01:04:25.620 | even if it's brief exercise.

01:04:27.700 | But the main tool of delaying caffeine 90 to 120 minutes

01:04:32.640 | after waking has immediate effects,

01:04:35.520 | but it also sets in motion a cascade or domino falls

01:04:39.800 | that lead to better sleep and more wakefulness

01:04:42.940 | the next night and the next day and so on and so forth.

01:04:46.700 | Now I realize there are some people who just simply cannot

01:04:49.700 | or will not delay their caffeine 90 to 120 minutes

01:04:52.580 | after waking for whatever reason.

01:04:54.700 | First off, let me say that if you are somebody

01:04:57.040 | who likes to wake up and do very intense exercise

01:04:59.760 | within the first 90 minutes after waking,

01:05:02.300 | well, in that case, it would be appropriate

01:05:03.780 | to ingest your caffeine just prior to doing that exercise.

01:05:06.640 | Not a problem, not a problem,

01:05:08.580 | but you should expect that the combination

01:05:11.660 | of drinking caffeine very shortly after waking

01:05:14.160 | plus exercising very intensely shortly after waking

01:05:17.300 | will increase the intensity of that early afternoon

01:05:21.580 | and afternoon fatigue that you feel.

01:05:23.300 | Now, for some people, that's a great thing.

01:05:24.680 | They can afford to take a nap or do non-sleep deep rest,

01:05:27.900 | step away from work and so forth.

01:05:29.560 | In that case, I strongly encourage you to do whatever it is

01:05:33.340 | that allows you to get regular exercise

01:05:35.100 | because regular exercise is going to be very beneficial.

01:05:38.300 | In fact, we did an entire episode called Toolkit for Fitness

01:05:41.220 | that describes a couple of different,

01:05:43.100 | but really one main structure that allows you

01:05:45.420 | to get the appropriate amount of resistance training

01:05:47.900 | and cardiovascular training

01:05:49.700 | and flexibility training throughout the week.

01:05:51.500 | I happen to follow that program

01:05:53.460 | and it works very well.

01:05:55.120 | And it does involve some of those workouts

01:05:58.200 | to come very early in the morning, shortly after waking.

01:06:01.380 | And in those cases, I do ingest caffeine just prior to those.

01:06:04.120 | So within 10, 20 minutes of waking.

01:06:06.500 | However, on other days,

01:06:08.300 | I personally delay my caffeine intake 90 to 120 minutes.

01:06:11.200 | And I've done that to great benefit.

01:06:13.240 | And most people, if not all people that try that

01:06:16.180 | have reported the same.

01:06:17.740 | I should mention that some people will find getting out

01:06:20.340 | to that 90 minutes to be excruciatingly difficult

01:06:23.120 | because they're so accustomed to ingesting caffeine

01:06:26.100 | close to waking up.

01:06:26.980 | In that case, maybe just push out your caffeine intake

01:06:29.260 | by about 15 minutes each day

01:06:31.580 | until you hit that 90 to 120 minute mark.

01:06:34.380 | And that will make it much easier.

01:06:35.420 | It might take you a week or so to get there.

01:06:36.820 | But once you get there,

01:06:37.860 | you'll find it to be quite easy to maintain.

01:06:40.260 | The other thing is that if you are somebody

01:06:41.900 | who insists on drinking caffeine very shortly after waking,

01:06:45.180 | I would encourage you to drink half of your caffeine then,

01:06:48.420 | and then the other half of your caffeine

01:06:50.980 | about an hour later.

01:06:52.020 | That also will help offset some of the afternoon crash

01:06:55.140 | for reasons related to the so-called kinetics of caffeine.

01:06:58.500 | Caffeine has a quarter life of about 12 hours.

01:07:01.120 | That means that if you were to ingest a cup of coffee

01:07:03.900 | at let's say 8 a.m. and let's say 100 milligram coffee,

01:07:07.960 | just for sake of simplicity,

01:07:10.000 | that about 25% of that caffeine action,

01:07:13.840 | we wouldn't really say 25 milligrams,

01:07:15.300 | but about 25% of that caffeine action

01:07:18.240 | will still be present at 8 p.m. that night,

01:07:23.240 | which is pretty remarkable.

01:07:24.600 | So there's a long arc of caffeine effects,

01:07:26.560 | and this is why it can impede sleep

01:07:27.900 | if we take caffeine in the afternoon.

01:07:30.700 | But again, if you're somebody who wakes up

01:07:32.620 | and you really need caffeine right away

01:07:34.180 | and you refuse to do this 90 to 120 minute delay thing

01:07:37.160 | that I'm talking about,

01:07:38.340 | well, then in that case,

01:07:39.340 | I would drink half of your caffeine upon waking

01:07:41.300 | and then a little bit more or the other half

01:07:43.980 | about an hour later,

01:07:46.260 | and that will extend the arc of that caffeine effects

01:07:49.100 | such that you don't need it again in the afternoon

01:07:51.140 | because you won't experience the afternoon crash.

01:07:53.380 | Because of the way caffeine works,

01:07:54.840 | I should mention that if you ingest caffeine

01:07:57.140 | on an empty stomach,

01:07:58.360 | it will have a more potent stimulant effect.

01:08:00.900 | That will also tend to increase the level of jitteriness

01:08:04.940 | that caffeine can produce.

01:08:06.500 | Later, I'll talk about ways to offset that jitteriness,

01:08:08.660 | but I'll just tell you one tool now.

01:08:10.480 | Many people opt to take 100 milligrams of theanine,

01:08:14.100 | T-H-E-A-N-I-N-E, theanine,

01:08:17.300 | as a way to offset some of that jitteriness.

01:08:19.600 | Theanine will reduce the jitteriness of caffeine,

01:08:22.640 | which is why many energy drink manufacturers

01:08:25.180 | and even some coffee manufacturers

01:08:27.100 | are now putting theanine in energy drinks

01:08:29.320 | and in ground coffee.

01:08:30.980 | Because no surprise,

01:08:33.020 | it allows people to consume more of that beverage

01:08:35.900 | and thereby purchase more of that beverage,

01:08:38.020 | which is what these vendors want,

01:08:39.780 | without feeling overly anxious and jittery.

01:08:42.300 | So you can take pill form theanine if you want

01:08:44.260 | with your caffeine.

01:08:45.100 | I don't tend to do that.

01:08:45.980 | Rather, I control the total dosage of my caffeine.

01:08:48.740 | I do tend to consume caffeine on an empty stomach

01:08:50.860 | because I do restrict my caffeine intake

01:08:52.460 | to the early part of the day.

01:08:54.500 | And I generally eat my first meal somewhere around 11 a.m.

01:08:58.460 | And then I generally eat my last meal sometime

01:09:00.440 | around 8 p.m. or so.

01:09:02.740 | Those are averages, I would say, plus or minus an hour.

01:09:05.900 | And that's not because I'm religiously following

01:09:08.460 | any kind of time-restricted feeding.

01:09:11.120 | It's just that tends to work best with my schedule

01:09:14.300 | and my appetite.

01:09:15.960 | But again, that's a general theme.

01:09:18.440 | There are days in which I wake up and I'm very hungry

01:09:20.200 | and I might ingest something, a small snack or something.

01:09:24.020 | Or if I'm meeting somebody for breakfast,

01:09:25.540 | sometimes I'll have breakfast, sometimes I won't.

01:09:27.960 | And so on and so forth.

01:09:29.140 | The point is that you can get away with drinking

01:09:31.540 | less caffeine to get the stimulant effect

01:09:33.820 | if you do it on an empty stomach.

01:09:35.500 | And if you're somebody who likes to exercise

01:09:37.380 | on an empty stomach, and I'm one of those people,

01:09:40.580 | well then ingesting caffeine just prior to exercise

01:09:43.740 | can be a fantastic tool.

01:09:45.360 | A little bit later, we'll talk about some of the

01:09:47.340 | physical performance enhancing effects of caffeine,

01:09:50.800 | but I'll just briefly jump to a point about that

01:09:54.220 | as we relate to morning exercise.

01:09:56.420 | If you are somebody who regularly ingest caffeine,

01:09:59.220 | and we can define regularly by if you've ingested caffeine

01:10:03.260 | every day for the last two weeks,

01:10:06.020 | you're a regular consumer of caffeine.

01:10:08.140 | Whereas if you're somebody who only ingest caffeine

01:10:10.140 | somewhere between two and four times per week,

01:10:12.560 | well then you are not a regular consumer of caffeine.

01:10:15.340 | You're an intermittent user of caffeine.

01:10:17.540 | Well, if you're somebody who's a regular user of caffeine,

01:10:19.960 | the performance enhancing effects of caffeine

01:10:22.340 | are going to be most dramatic

01:10:25.100 | if you take two or three days off from drinking caffeine,

01:10:27.820 | which to my mind is a,

01:10:30.020 | I don't want to call myself a caffeine addict,

01:10:31.420 | but a regular caffeine user,

01:10:32.900 | that's a horrible notion to me, an aversive notion,

01:10:36.280 | because I do like the effects of caffeine so much.

01:10:38.660 | But if you really want to see the maximum performance

01:10:40.980 | enhancing effects of caffeine,

01:10:42.640 | you will do either one of two things.

01:10:44.340 | You will either abstain from caffeine for a few days

01:10:47.020 | or three days prior to ingesting caffeine,

01:10:49.740 | or you will use caffeine on an empty stomach.

01:10:54.180 | It's very clear that caffeine on an empty stomach

01:10:56.740 | enhances both the mental

01:10:58.560 | and physical enhancing effects of caffeine.

01:11:00.580 | And of course, all of that has to be stated

01:11:02.300 | on the backdrop of consideration that if you,

01:11:04.980 | you know, you're very, very hungry,

01:11:06.200 | it can be make it hard to concentrate

01:11:07.740 | and so on and so forth.

01:11:08.560 | So I'm not encouraging people to starve themselves

01:11:10.840 | by any means, certainly don't do that.

01:11:13.340 | But if you want to maximize

01:11:14.740 | the performance enhancing effects of caffeine,

01:11:16.660 | you will consume it on an empty stomach.

01:11:18.120 | And then as a final point to that,

01:11:20.300 | caffeine is a diuretic.

01:11:22.120 | It causes us to lose fluid

01:11:23.980 | and along with that fluid to excrete sodium

01:11:26.460 | because of the effects of caffeine

01:11:28.180 | on various processes within the kidney.

01:11:30.740 | So one thing that works very well

01:11:32.780 | to maintain mood and alertness,

01:11:36.100 | longer given a certain amount of caffeine intake

01:11:39.600 | and to avoid the jitteriness

01:11:41.100 | and what can sometimes feel like a crash

01:11:43.140 | or low blood sugar feeling or even blurry vision

01:11:45.580 | is to make sure that you consume

01:11:47.680 | at least an equal volume of water with your caffeine.

01:11:51.740 | And ideally that water would contain

01:11:53.180 | maybe a small pinch of salt

01:11:54.340 | or some sort of electrolyte drink or powder rather.

01:11:57.580 | For me, I use Element.

01:11:58.780 | Full disclosure, they are a podcast affiliate and sponsor,

01:12:02.020 | but you don't need to do that.

01:12:03.280 | You could simply just have a glass of water

01:12:05.740 | alongside your coffee or espresso

01:12:07.780 | or your yerba mate and just put a small pinch of sea salt

01:12:11.180 | in that or even just plain table salt.

01:12:13.180 | And that will help offset

01:12:14.400 | some of the jitteriness of caffeine.

01:12:16.020 | A lot of people think that when they ingest caffeine,

01:12:18.700 | they get the jitteriness and crash

01:12:20.020 | because their blood sugar is low.

01:12:21.820 | And while that can be the case,

01:12:23.040 | oftentimes it's simply because of the excretion of sodium

01:12:25.800 | that's occurred when they've ingested caffeine.

01:12:27.740 | So I encourage you to hydrate well

01:12:30.380 | and to hydrate with something

01:12:32.140 | that contains a little bit of sodium.

01:12:33.820 | Obviously not so much that it increases hypertension

01:12:35.900 | or something of that sort,

01:12:36.740 | but a small amount of sodium

01:12:37.900 | or an electrolyte drink like Element.

01:12:39.400 | And there are other electrolyte drinks out there

01:12:41.780 | that can accomplish the same, of course.

01:12:43.360 | Just a couple of quick notes about theanine

01:12:45.300 | because there are a growing number of products out there

01:12:48.480 | that contain theanine.

01:12:49.500 | And there's certainly a growing number of people out there

01:12:51.620 | who are using theanine

01:12:52.860 | for the effect that I described before,

01:12:54.300 | which is to offset some of the jitteriness

01:12:56.220 | associated with caffeine containing beverages or foods.

01:12:59.540 | And of course, I should mention that

01:13:01.940 | I've talked about the effects of theanine on sleep

01:13:05.780 | at that sleep toolkit that you can find as a free download.

01:13:08.580 | You don't even have to sign up for anything.

01:13:10.080 | You can just download it from hubermanlab.com,

01:13:11.900 | go to the menu, go to newsletter,

01:13:13.180 | you'll see the toolkit for sleep.

01:13:14.820 | You'll see that the so-called sleep stack

01:13:17.420 | that I use and recommend includes magnesium threonate,

01:13:21.860 | something called apigenin and theanine.

01:13:24.720 | Although that sleep stack is designed to be taken

01:13:27.940 | 30 to 60 minutes prior to sleep.

01:13:29.860 | And I make the point there and I'll make it again here,

01:13:32.320 | that ingesting theanine prior to sleep is not a good idea

01:13:36.500 | if you are somebody who tends to have very vivid dreams,

01:13:39.380 | night terrors or night sleepwalking, excuse me, et cetera.

01:13:44.380 | In that case, eliminate theanine from the sleep stack.

01:13:47.480 | However, a number of people are using theanine

01:13:49.380 | and products are using theanine to offset jitteriness

01:13:52.300 | from caffeine containing products during the daytime,

01:13:55.100 | daytime consumption that is.

01:13:57.180 | A couple of notes about theanine.

01:13:58.540 | Theanine is something that is present in green tea, right?

01:14:01.700 | It's now been created as a supplement.

01:14:03.740 | It's what's called a non-protein amino acid.

01:14:05.920 | So while there are amino acids and proteins,

01:14:07.740 | there are of course amino acids and non-proteins

01:14:10.180 | and theanine is one such non-protein amino acid.

01:14:12.860 | Theanine tends to stimulate the so-called glutamate

01:14:17.420 | and glutamine pathway.

01:14:19.280 | It's actually very similar to glutamate and glutamine.

01:14:22.500 | And it has a lot of effects on a lot of different aspects

01:14:25.780 | of the nervous system.

01:14:26.900 | But the general effect of theanine is to compete

01:14:30.060 | for the receptors for certain neurotransmitters.

01:14:33.060 | And the neurotransmitters I'm referring to

01:14:35.380 | are all excitatory neurotransmitters, things like glutamate.

01:14:38.400 | And they govern a tremendous amount of our daily thinking

01:14:41.400 | and action and feeling, et cetera,

01:14:43.060 | because they're present at so many connections

01:14:44.720 | between neurons in the brain.

01:14:46.180 | Theanine competes for the receptors for glutamate

01:14:51.100 | and tends to reduce our overall levels of alertness.

01:14:54.900 | So really when people take theanine along with caffeine,

01:14:58.020 | what they're doing is they're really taking a slight,

01:15:01.620 | I don't want to call it depressant

01:15:03.060 | to the point where it misleads people

01:15:04.580 | and makes people think that it will make you depressed.

01:15:06.940 | The word is a little bit misleading,

01:15:08.300 | but tends to reduce or blunt some of the more excitatory

01:15:12.580 | pro-alertness actions of neurons in the brain.

01:15:15.660 | So when you take it alongside caffeine,

01:15:17.160 | tends to quote unquote even things out a bit.

01:15:19.740 | I should mention that the dosages of theanine

01:15:22.020 | that are effective for offsetting

01:15:23.980 | the jitteriness of caffeine is 200 to 400 milligrams.

01:15:27.660 | And the studies that I was able to find

01:15:30.200 | showed that essentially up to 900 milligrams per day

01:15:33.140 | can be safe, but that's a very high dosage of theanine.

01:15:36.420 | In fact, so much so that it might increase sleepiness

01:15:39.860 | to the point where it wouldn't feel good.

01:15:41.940 | There are also some positive effects

01:15:43.980 | of daytime consumption of theanine

01:15:46.380 | that are independent of reducing the jitteriness of caffeine.

01:15:50.040 | For instance, there's a study demonstrating

01:15:51.420 | that 17 days of ingesting theanine

01:15:54.020 | at these 200 to 400 milligram dosage

01:15:56.680 | of one to three times per day

01:15:58.780 | can reduce depression and anxiety.

01:16:02.400 | There are also some good data out there

01:16:03.820 | showing that theanine can have positive effects

01:16:06.300 | on endothelial cells, so blood vessels,

01:16:08.200 | capillaries, and so on,

01:16:09.780 | and increase some of the function of blood vessels,

01:16:12.260 | allowing them to pass more blood through them,

01:16:15.700 | give them a little bit more elasticity, if you will.

01:16:18.220 | So theanine has certain pro-sleep effects

01:16:21.020 | if it's taken prior to sleep.

01:16:22.380 | It can enhance the quality, depth, and duration of sleep.

01:16:25.900 | Again, if you're a sleepwalker

01:16:27.300 | or somebody who has extremely vivid dreams

01:16:29.100 | from which you wake up in the middle of the night,

01:16:31.380 | probably best to leave out theanine

01:16:32.880 | or maybe reduce the dosage down to 100 milligrams,

01:16:35.260 | and if that's still too much, then eliminate it completely.

01:16:37.940 | But theanine can be terrific

01:16:40.100 | for enhancing quality, depth, and duration of sleep.

01:16:42.760 | It can also reduce the jitteriness associated

01:16:46.700 | with caffeine-containing beverages and foods,

01:16:49.980 | and it has certain antidepressant

01:16:52.780 | and pro-endothelial effects.

01:16:55.180 | That is, it can offset depression, it can offset anxiety,

01:16:59.540 | although those are minor effects, subtle effects,

01:17:03.080 | and it has been shown to improve endothelial cell,

01:17:06.160 | that is vessel and capillary function and structure,

01:17:10.420 | in ways that can be beneficial for both brain and body.

01:17:13.700 | Now, one final point about theanine

01:17:15.180 | that's worth paying attention to

01:17:16.600 | is that the kinetics of theanine are such

01:17:19.040 | that you don't need to take theanine

01:17:21.420 | every time you ingest a caffeinated beverage.

01:17:23.780 | When we ingest caffeine, the peak effects of caffeine

01:17:28.840 | occur about 30 minutes after we drink it,

01:17:32.860 | and there, I'm assuming one takes it all at once,

01:17:35.500 | and this is a key point that we'll come back to later,

01:17:37.940 | rather than sipping your coffee slowly

01:17:39.620 | over a couple of hours or an hour.

01:17:42.180 | If you drink all 200 or 300 milligrams of caffeine

01:17:45.340 | in your coffee, 600 milligrams of your coffee,

01:17:48.420 | if you're getting one of those commercial coffees,

01:17:51.700 | and you take theanine along with it,

01:17:53.260 | theanine will block some of the jitteriness

01:17:56.800 | and anxiety-inducing effects of caffeine that can occur

01:18:00.840 | for much longer than the effects that caffeine lasts.

01:18:04.000 | So the peak in theanine occurs

01:18:05.500 | about an hour after ingestion.

01:18:07.240 | I suppose if you wanted to get really fancy

01:18:10.500 | and really dial in the kinetics,

01:18:12.400 | you could ingest theanine about half hour

01:18:14.080 | before you ingest your caffeine,

01:18:15.300 | but I think that's getting a little bit excessive

01:18:18.180 | in terms of controlling your microenvironment, if you will.

01:18:21.680 | I think it would be perfectly fine

01:18:22.940 | to take a 100 to 200 milligram capsule of theanine

01:18:27.940 | along with your coffee or tea and so forth,

01:18:31.660 | and just realize that if you drink more caffeine

01:18:34.220 | or you extend your caffeine intake over several hours,

01:18:37.180 | that you don't necessarily have to take theanine

01:18:39.220 | repeated times throughout the day.

01:18:41.020 | I'd like to take a brief break

01:18:42.660 | and thank our sponsor, Inside Tracker.

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01:19:03.900 | The problem with a lot of blood and DNA tests out there,

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01:19:45.600 | Let's talk for a moment about when to avoid caffeine.

01:19:48.620 | And in the same stroke,

01:19:50.340 | let's also talk about some of the myths around caffeine.

01:19:53.620 | For instance, one of the major myths around caffeine

01:19:56.060 | is that it can increase osteoporosis.

01:19:59.280 | Turns out that while there is a relationship, of course,

01:20:02.300 | between calcium and osteoporosis,

01:20:04.740 | that is reductions in bone density,

01:20:06.640 | and it is the case that caffeine can extract calcium

01:20:11.580 | from certain tissues,

01:20:13.000 | the large-scale studies that are out there

01:20:15.860 | essentially prove that if people are ingesting

01:20:18.420 | enough calcium through their diet,

01:20:20.740 | which most everybody is,

01:20:22.560 | although certainly there are some people

01:20:24.080 | that need to supplement calcium

01:20:25.540 | or make it a point to consume more calcium-containing foods,

01:20:28.940 | but assuming that you are getting

01:20:30.260 | adequate levels of calcium,

01:20:31.660 | there is no direct relationship

01:20:34.380 | between caffeine intake and osteoporosis,

01:20:37.500 | at least not that I'm aware of.

01:20:39.420 | I know this was debated for a number of years

01:20:41.360 | in the literature,

01:20:42.400 | but the literature seems to have arrived

01:20:44.840 | at a general consensus now

01:20:46.740 | that caffeine itself is not going to create

01:20:49.660 | or exacerbate osteoporosis,

01:20:51.500 | provided people are getting enough calcium

01:20:53.600 | through their diet, that is through foods,

01:20:57.060 | through supplementation, or both.

01:20:59.740 | Some of the other myths around caffeine are that,

01:21:01.820 | for instance, caffeine will reduce testosterone levels

01:21:05.980 | or will reduce estrogen levels.

01:21:08.720 | Other myths out there are an exact opposite to that,

01:21:13.300 | that caffeine will increase testosterone levels,

01:21:15.980 | in particular, free testosterone levels.

01:21:18.340 | There've been some large-scale studies

01:21:20.140 | addressing the hormone effects of caffeine.

01:21:22.600 | They are a little bit difficult to do.

01:21:24.560 | I should just mention that caveat.

01:21:26.100 | And the reason they are difficult to do

01:21:28.080 | is because 90% of adults are consuming caffeine,

01:21:31.620 | and therefore, you can imagine,

01:21:33.260 | it's very hard to find a control group

01:21:35.780 | to compare the caffeine consumers to.

01:21:38.540 | In particular, a control group that's well-controlled

01:21:41.860 | for other things like lifestyle, diet, exercise, et cetera.

01:21:45.220 | However, when one controls as well as one can

01:21:50.480 | for all the various factors that could impact hormones,

01:21:54.240 | what one discovers is that caffeine intake,

01:21:56.880 | at least at the dosages we talked about earlier,

01:21:58.760 | one to three milligrams per kilogram of body weight,

01:22:02.140 | or even up to double that,

01:22:04.220 | that there are no consistent increases or reductions

01:22:09.220 | in testosterone or estrogen in men or women

01:22:13.360 | that can be directly attributed to the caffeine intake.

01:22:16.320 | And I say directly attributed

01:22:17.580 | because in these association studies,

01:22:19.500 | one always has to wonder, for instance,

01:22:21.300 | if because people are ingesting more caffeine,

01:22:24.260 | they have more energy and therefore exercising more,

01:22:26.560 | and exercise is known to have effects

01:22:28.300 | on testosterone, estrogen, and other hormones,

01:22:30.740 | whether or not the effects of caffeine on those hormones

01:22:33.220 | is indirect and so on and so forth.

01:22:34.900 | And this all just underscores the challenges

01:22:36.820 | of doing studies on humans in the wild,

01:22:39.040 | in their natural habitat of living,

01:22:40.820 | as opposed to an acute study, as it's called,

01:22:42.700 | that brings someone into the laboratory

01:22:44.180 | and studying them just for those hours or moments.

01:22:47.340 | With all that said, there does appear to be a relationship

01:22:50.420 | between caffeine intake and so-called sex hormone

01:22:53.580 | and binding globulin, which is a protein present

01:22:58.460 | in the body of both men and women

01:23:01.700 | that binds to the sex steroid hormones,

01:23:04.760 | testosterone and estrogen,

01:23:05.980 | and prevents them from being in their free or active form.

01:23:08.860 | It has been shown that ingestion of caffeine,

01:23:13.580 | even in the sorts of dosage ranges that are considered safe

01:23:16.220 | and that we've been discussing,

01:23:17.480 | can increase sex hormone binding globulin,

01:23:20.620 | such that it can slightly reduce overall levels

01:23:23.860 | of free testosterone and free estradiol in women.

01:23:28.220 | Now, those effects are relatively minor, but they do exist.

01:23:32.160 | If any of you are interested in reading further

01:23:33.860 | into the effects of caffeine on hormones,

01:23:36.340 | I'll just refer you to a couple of studies.

01:23:38.420 | We will link to this in the show note caption.

01:23:40.420 | The title of the study is

01:23:41.820 | "Consumption of Caffeinated Beverages

01:23:43.300 | "and Serum Concentrations of Sex Steroid Hormones

01:23:45.860 | "in U.S. Men."

01:23:47.100 | And within this study, there's a reference

01:23:49.420 | to a equally-sized empowered study done on women,

01:23:54.260 | both of which converged on the same conclusion,

01:23:56.780 | by examining more than 1,000,

01:23:59.300 | so in this case, 1,410 men, or more than 1,000 women,

01:24:03.360 | that there are increases in sex hormone binding globulin

01:24:06.340 | associated with increased intake of coffee in particular,

01:24:10.420 | but they were able to narrow that down specifically

01:24:14.420 | to ingestion of caffeine.

01:24:15.740 | So it's not coffee per se that's causing the increase

01:24:18.380 | in sex hormone binding globulin,

01:24:20.120 | it's actually caffeine itself.

01:24:22.220 | Now, again, the increases in sex hormone binding globulin

01:24:25.380 | were not so significant that, at least to my mind,

01:24:27.700 | they seem like a concern,

01:24:29.100 | although I think that it is worth noting

01:24:31.540 | that if you're going to consume caffeine,

01:24:33.140 | that you'd probably want to consume caffeine

01:24:35.620 | in a way that is in dosages and with the sort of timing

01:24:40.260 | that will allow you to get away with ingesting caffeine,

01:24:42.920 | but not to excess, so to derive the benefits of caffeine

01:24:46.900 | without, for instance,

01:24:47.780 | driving up sex hormone binding globulin too far.

01:24:50.540 | Now, why would that be a good idea?

01:24:51.780 | Why would you want to make sure

01:24:52.860 | that you have enough free testosterone and free estrogen?

01:24:55.760 | Well, some of that is related to the acute effects

01:24:58.600 | of those hormones in terms of wellbeing and libido

01:25:01.700 | and strength and mood, et cetera,

01:25:04.560 | but some of it is also related

01:25:05.740 | to the longer term effects of sex steroid hormones.

01:25:09.620 | Many people don't realize this,

01:25:11.380 | but the sex steroid hormones operate on the receptors

01:25:14.420 | at the surface of cells to have immediate effects,

01:25:17.020 | but they also can enter cells

01:25:19.100 | and actually go into the nucleus of cells

01:25:20.960 | where the DNA of those cells are contained

01:25:22.960 | and control gene expression in those cells.

01:25:25.460 | So the sex steroid hormones, testosterone and estrogen

01:25:27.880 | are controlling a lot of different cellular functions

01:25:30.500 | over long periods of time.

01:25:31.900 | So blunting their action over long periods of time

01:25:35.140 | is probably not a great idea.

01:25:36.900 | But again, at the dosages of caffeine

01:25:38.500 | that we're talking about today,

01:25:40.640 | one to three milligrams per kilogram of body weight,

01:25:42.940 | unlikely that the increases in sex hormone binding globulin

01:25:46.360 | that one experiences from that are going to be detrimental.

01:25:48.980 | And certainly the positive effects of caffeine

01:25:50.800 | that one experiences in terms of mental performance

01:25:53.380 | and physical performance,

01:25:54.360 | and the fact that it increases energy

01:25:56.160 | to do the sorts of things like exercise

01:25:58.620 | that we know can profoundly improve hormone profiles.

01:26:01.940 | Twofold or threefold improvement in hormone profiles.

01:26:07.120 | In that case, it seems that ingesting caffeine

01:26:10.120 | is overall a good thing provided it's not in excess.

01:26:13.300 | That also makes this the appropriate time to mention

01:26:16.020 | one of the more impressive effects of caffeine,

01:26:18.420 | which is on overall levels of mood and mental health.

01:26:21.640 | There are several studies on this,

01:26:23.640 | but the one that I'm particularly fond of

01:26:26.200 | was published in 2019 in Psychiatry Research.

01:26:29.740 | And the title of the paper is

01:26:31.100 | Inverse Association Between Caffeine Intake

01:26:33.360 | and Depressive Symptoms in US Adults.

01:26:35.560 | And these are data from the National Health

01:26:37.560 | and Nutrition Examination Survey.

01:26:39.560 | And the basic takeaway is that while of course,

01:26:42.180 | there are a ton of different factors

01:26:44.200 | that are going to relate to whether or not

01:26:46.180 | people are depressed or not, life circumstances,

01:26:48.520 | genetics, and so on, that,

01:26:51.080 | and here I'm quoting from the study,

01:26:52.280 | caffeine's psychostimulant properties,

01:26:54.080 | that just means the ability to make us feel more alert

01:26:56.440 | and positive, appear to protect against depressive symptoms.

01:27:00.080 | And of course, they acknowledge

01:27:01.160 | that additional studies are needed.

01:27:02.880 | But this is just one of several studies

01:27:04.880 | pointing to the fact that people who regularly ingest

01:27:06.960 | caffeine in the appropriate dosages

01:27:09.260 | do seem to enjoy an anti-depressive effect overall.

01:27:12.960 | I wouldn't want anyone to consider caffeine

01:27:15.420 | a treatment for severe depression,

01:27:18.280 | or at least not alone a treatment for severe depression,

01:27:21.060 | but provided the anxiety inducing effects of caffeine

01:27:23.800 | can be kept in check through use of theanine

01:27:25.960 | or making sure that the dosage

01:27:27.860 | and the timing of caffeine ingestion is correct,

01:27:29.720 | then caffeine overall seems to be good for our mood

01:27:32.940 | and prevent depression or at least keep depression at bay

01:27:37.080 | when depression might otherwise surface or be more severe.

01:27:41.120 | And of course, there are the don'ts

01:27:42.780 | surrounding caffeine intake.

01:27:45.320 | As it relates to sleep, and to put it very simply,

01:27:48.860 | sleep that is getting enough quality sleep each night

01:27:52.280 | is the foundation.

01:27:53.680 | It is the bedrock of mental health,

01:27:55.320 | physical health and performance.

01:27:56.720 | Sleep and the power of sleep far exceeds

01:27:59.840 | any nootropic you could ever take,

01:28:02.200 | any prescription drug you could ever take,

01:28:04.400 | any health promoting tool for your immune system,

01:28:07.800 | your metabolism, your mental function,

01:28:10.320 | your physical function you could ever take.

01:28:11.880 | Sleep is the bedrock.

01:28:13.800 | I know a lot of people experience challenge with sleep.

01:28:17.360 | Nobody is perfect about sleep.

01:28:18.840 | That's important to keep in mind.

01:28:20.580 | I think a good goal is to get enough quality sleep

01:28:24.220 | of sufficient duration, 80% of the nights of your life,

01:28:26.900 | and then as much as possible to make sure

01:28:28.860 | that the remaining 20% of nights,

01:28:30.840 | you're not getting enough sleep for good reasons

01:28:33.000 | as opposed to hard reasons.

01:28:33.840 | Good reasons would include raising children.

01:28:36.060 | That's important.

01:28:36.920 | After all, every species desires to make more of itself

01:28:41.020 | and to preserve and extend the wellbeing of its young.

01:28:45.040 | So child rearing is a perfectly legitimate reason

01:28:47.920 | to get a lack of sleep,

01:28:49.780 | but you really want to strive to get quality sleep

01:28:53.020 | most nights of your life.

01:28:54.280 | Which means that even if you're somebody

01:28:57.520 | who can "drink an espresso" and then fall right asleep,

01:29:01.060 | that you avoid caffeine intake

01:29:03.940 | in the 12 hours prior to sleep.

01:29:06.880 | I realize not everyone will be able to do that.

01:29:09.020 | In fact, I sometimes violate that.

01:29:10.860 | So I tend to go to sleep around 10 p.m. every night,

01:29:14.620 | sometimes 11, occasionally 12 midnight,

01:29:18.280 | but usually around 10 p.m. every night.

01:29:21.200 | I confess that my last ingestion of caffeine

01:29:25.940 | is not always 10 a.m. or prior to that.

01:29:29.560 | So sometimes I will have caffeine up until 11 a.m.

01:29:32.580 | or maybe noon.

01:29:34.320 | And very, very rarely I'll have an afternoon coffee

01:29:37.420 | or espresso or non calorie containing soda

01:29:42.420 | or tea or something of that sort.

01:29:45.520 | But I really try to restrict my caffeine intake

01:29:48.080 | to the early part of my day that is before noon,

01:29:51.260 | given that I go to sleep around 10 p.m. each night.

01:29:54.440 | And I strongly encourage everyone out there

01:29:57.220 | to try and limit their afternoon caffeine intake.

01:29:59.920 | This is something that Dr. Matt Walker,

01:30:03.300 | who's an expert sleep researcher

01:30:05.780 | out of University of California, Berkeley,

01:30:07.700 | psychology and neuroscience department there,

01:30:09.540 | author of the incredible book, "Why We Sleep."

01:30:11.380 | He's been on this podcast, many other podcasts,

01:30:14.600 | talking about the importance of sleep.

01:30:16.500 | He will remind us, and I'll remind you now

01:30:19.100 | that the quarter life of caffeine is 12 hours.

01:30:23.140 | I mentioned this earlier, but I'm going to repeat it again.

01:30:25.140 | And that means that if you ingest caffeine at noon,

01:30:29.420 | 25% of its effects, more or less,

01:30:32.180 | okay, I'm using broad stroke here

01:30:33.420 | to talk about quarter life.

01:30:34.860 | 25% of that is still going to be bioactive

01:30:38.380 | at midnight that night,

01:30:39.860 | which will disrupt the early phase of your night,

01:30:42.580 | the amount of slow wave sleep,

01:30:44.100 | which then in turn will disrupt

01:30:46.460 | the amount of rapid eye movement sleep,

01:30:47.980 | which will disrupt your emotional processing

01:30:50.660 | during the following day and so on and so forth.

01:30:53.140 | None of this is to say

01:30:54.440 | that if you have the occasional cup of coffee

01:30:56.180 | in the afternoon, that's going to completely demolish

01:30:58.300 | your sleep-wake cycle forever.

01:31:00.040 | But I really encourage people to avoid drinking caffeine

01:31:03.260 | in the 12 hours prior to sleep.

01:31:05.520 | And if you can't do that within the 10 hours prior to sleep,

01:31:07.860 | and if you can't do that within the eight hours

01:31:09.600 | prior to sleep, so really try and limit your caffeine intake

01:31:12.820 | in the eight to 12 hours prior to going to sleep at night.

01:31:16.220 | And of course, slow wave sleep, aka deep sleep,

01:31:18.540 | is the sleep that's associated with somewhat mundane dreams,

01:31:23.180 | which makes it sound like it might not be that important,

01:31:25.180 | but it's also the sleep that's associated

01:31:28.180 | with growth hormone release,

01:31:29.600 | which is important for protein synthesis,

01:31:32.560 | repair of all bodily tissues and metabolism,

01:31:35.520 | and slow wave sleep is also critically attached

01:31:39.000 | to your immune system's ability

01:31:40.780 | to clear out bacteria and viruses

01:31:42.600 | that might otherwise infect your tissues.

01:31:44.620 | Now I'd like to talk about caffeine and performance,

01:31:47.440 | and that includes both mental performance

01:31:49.260 | and physical performance.

01:31:50.960 | Now I'd like to talk about caffeine

01:31:53.520 | and its positive effects on performance

01:31:55.940 | when used correctly.

01:31:57.700 | And here we are referring to both mental performance

01:32:00.460 | and physical performance.

01:32:02.760 | The exploration of caffeine as a pro-performance tool

01:32:06.720 | has been explored since the 1930s,

01:32:09.640 | at least that's some of the earliest

01:32:10.920 | documented literature on this.

01:32:13.280 | Although I have to imagine,

01:32:14.440 | given that people have been using caffeine

01:32:16.200 | for much longer than that,

01:32:17.860 | that long ago, somebody realized that

01:32:20.540 | by ingesting a certain plant,

01:32:22.380 | that they felt much more alertness

01:32:23.980 | and were able to hunt and gather

01:32:25.700 | or do any number of different things better,

01:32:27.540 | and as a consequence,

01:32:28.780 | decided to consume more of that plant.

01:32:32.320 | Now, these days we consume a lot of caffeine

01:32:34.320 | in the form of coffee and tea mainly,

01:32:36.000 | and some people consume it in the form of caffeine tablets

01:32:39.340 | or energy drinks, et cetera.

01:32:41.260 | Across the board, one finds that caffeine intake

01:32:45.680 | at a level of one to three milligrams per kilogram

01:32:47.960 | of body weight improves reaction time.

01:32:51.220 | That is, it reduces the amount of time

01:32:52.960 | to take a physical action

01:32:54.720 | or to answer a question correctly

01:32:58.720 | with a verbal response.

01:33:01.120 | It can also improve coordination,

01:33:02.720 | it can also improve memory,

01:33:04.720 | although I do want to mention that

01:33:06.660 | whereas most studies of the effects of caffeine

01:33:09.480 | on improving mental and physical performance

01:33:12.200 | involve taking caffeine at one to three milligrams

01:33:15.860 | per kilogram of body weight

01:33:16.980 | before the mental task or physical task,

01:33:20.600 | there is also a pro-performance effect of caffeine on memory

01:33:24.560 | if one takes caffeine after learning certain material,

01:33:28.240 | or I should say, being exposed to certain material.

01:33:31.920 | We'll come back to that in a few minutes.

01:33:34.640 | If one examines reaction time, mood, alertness,

01:33:39.200 | focus, and memory,

01:33:42.520 | or the ability to call up information from memory,

01:33:45.200 | or physical dexterity, power output, endurance,

01:33:50.200 | and overall feelings of wellbeing

01:33:53.420 | during exercise and exertion,

01:33:56.560 | caffeine has been shown in numerous studies

01:33:59.480 | in both men and women

01:34:01.040 | to improve all of those metrics significantly.

01:34:04.280 | So this is all just to say that caffeine

01:34:07.800 | is an incredible performance-enhancing tool.

01:34:10.280 | Now, what's not obvious from the statement

01:34:12.480 | that caffeine is a performance-enhancing tool

01:34:15.120 | across the board and in men and women

01:34:17.500 | and in different contexts

01:34:19.080 | is that the way in which caffeine is taken

01:34:22.160 | is very important.

01:34:24.480 | Because 90% or more of adults consume caffeine,

01:34:29.340 | finding controls for studies of caffeine

01:34:33.160 | is really challenging.

01:34:34.160 | That is, finding people who don't ingest caffeine regularly

01:34:37.340 | is a very challenging task for the researcher.

01:34:40.440 | And as a consequence, many of the studies of caffeine

01:34:43.600 | on human beings involve depriving regular caffeine users

01:34:47.440 | of caffeine and then examining the effects of caffeine

01:34:51.800 | given after a period of, say, five to 15 days of abstinence

01:34:56.100 | in a person that is essentially experiencing

01:34:58.520 | mild withdrawal symptoms

01:35:00.880 | because they haven't had the caffeine

01:35:02.140 | that they were used to getting.

01:35:03.400 | So this is an important point.

01:35:04.640 | And it's a point that likely exacerbates

01:35:07.740 | the observed pro-performance effects of caffeine.

01:35:11.080 | Now, all of that isn't necessarily a problem,

01:35:13.120 | provided you keep it in mind.

01:35:15.240 | And it actually points to a way in which,

01:35:18.500 | even if you're a regular caffeine user,

01:35:20.680 | you can extract more of the benefits of caffeine.

01:35:23.160 | The simplest way to do this, for instance,

01:35:25.220 | is to look back to what we talked about earlier

01:35:28.440 | in terms of the need to have most of your cortisol increase

01:35:32.040 | restricted to the hour or hours just after waking

01:35:35.400 | in terms of mood and alertness and performance.

01:35:38.380 | One of the ways to increase the peak of that cortisol

01:35:41.800 | early in the day is to consume caffeine

01:35:45.600 | shortly after that peak occurs.

01:35:48.240 | And this was really nicely demonstrated

01:35:50.420 | in a study entitled caffeine stimulation

01:35:52.900 | of cortisol secretion across the waking hours

01:35:55.240 | in relation to caffeine intake levels.

01:35:57.760 | We will provide a link to this study.

01:35:59.440 | It's a somewhat complicated study

01:36:01.260 | because they looked at a bunch of different times of day

01:36:03.820 | for caffeine intake.

01:36:05.540 | And I should mention this study,

01:36:07.200 | they use this 300 milligrams per day

01:36:09.480 | or 600 milligrams per day.

01:36:11.220 | So that's quite high,

01:36:12.180 | although for people of sufficient body weight

01:36:14.380 | and who are accustomed to taking caffeine,

01:36:15.880 | it's certainly not going to be in excess

01:36:18.220 | of what a lot of people out there are taking.

01:36:20.480 | But basically what they observed was the following.

01:36:23.400 | Cortisol responses to caffeine are reduced,

01:36:27.040 | but not eliminated in people who consume caffeine

01:36:29.880 | on a daily basis.

01:36:31.160 | What this means is that if you wake up

01:36:33.120 | and as I recommended earlier,

01:36:35.000 | you avoid drinking caffeine for the first 90 to 120 minutes

01:36:38.880 | after waking, but you do get some sunlight

01:36:40.900 | or other bright light in your eyes in that time,

01:36:43.740 | maybe even get some exercise in that time,

01:36:45.440 | which would be even better.

01:36:46.880 | And then you ingest caffeine,

01:36:48.240 | you will get a further increase in cortisol,

01:36:50.720 | which provided it's restricted

01:36:52.880 | to the early part of the day

01:36:53.900 | is a good thing overall for mood and alertness.

01:36:56.600 | So this is a simple performance enhancing tool,

01:36:59.980 | which is to stack caffeine

01:37:01.400 | on the tail of that early cortisol peak.

01:37:04.400 | I should also mention however, that in this study,

01:37:06.800 | they had people do a five day caffeine abstinence

01:37:10.260 | prior to being tested with 300 milligrams

01:37:13.620 | or 600 milligrams of caffeine.

01:37:15.560 | So the simple tool to extract from this

01:37:17.520 | and other studies like it,

01:37:18.920 | is that if you want to experience

01:37:20.280 | the maximum alertness promoting effects of caffeine

01:37:23.440 | when you adjust it early in the day,

01:37:25.640 | you would abstain from caffeine for five days

01:37:28.220 | and then ingest caffeine 90 to 120 minutes after waking.

01:37:31.700 | I would still hope that you were doing all the other things

01:37:33.600 | that I described, morning sunlight exercise,

01:37:35.280 | et cetera, correctly, but regardless,

01:37:38.040 | it's very clear that a five day abstinence from caffeine,

01:37:40.840 | however painful that might be,

01:37:42.760 | will increase the performance enhancing effects

01:37:45.080 | of caffeine when you take caffeine on that sixth day.

01:37:48.200 | Now, I'm sure many of you out there are saying,

01:37:50.400 | why would I ever want to abstain from caffeine

01:37:52.780 | for five days in order to just get this

01:37:54.680 | six day performance enhancing effect?

01:37:57.120 | Well, there are a couple of reasons for doing that.

01:37:58.540 | Perhaps you're planning to travel to a new time zone

01:38:02.880 | and you want to use caffeine as a stimulant

01:38:04.840 | to stay up during the day in the new time zone.

01:38:07.340 | That's a somewhat unusual case.

01:38:09.100 | Others of you might be interested

01:38:10.440 | in the pro-physical performance effects of caffeine.

01:38:13.760 | We'll talk more about these in a little bit,

01:38:15.760 | but you want to get the maximum strength increase

01:38:18.160 | or the maximum endurance increase from ingesting,

01:38:21.620 | in this case, 300 to 600 milligrams of caffeine.

01:38:25.020 | Well, in that case, abstaining from caffeine for five days

01:38:27.760 | will greatly exacerbate the pro-performance effects

01:38:31.160 | of caffeine when you take it on that sixth day.

01:38:33.800 | Although admittedly, those five days are likely

01:38:35.800 | to be pretty painful if you're a regular caffeine user.

01:38:38.440 | Another variation on this, however,

01:38:39.920 | might be to have the amount of caffeine

01:38:42.580 | that you ingest on a daily basis

01:38:44.680 | and then go back to your regular level of caffeine intake

01:38:47.520 | on that day in which you need the caffeine

01:38:49.540 | to really boost your mood, energy, and performance.

01:38:51.960 | Another reason why you might want to abstain from caffeine

01:38:54.800 | or reduce your caffeine intake for a period of time

01:38:56.780 | and then go back to your regular caffeine intake

01:38:59.220 | is simply to identify how much of an effect caffeine

01:39:03.240 | is really having on your overall level

01:39:05.380 | of daily functioning and mood.

01:39:08.040 | This was something that was actually covered

01:39:09.420 | in beautiful detail in a book by Michael Pollan

01:39:11.780 | all about caffeine, it's available on Audible.

01:39:14.180 | I really enjoyed that book.

01:39:16.320 | It describes his experience with the decision

01:39:18.940 | to completely abstain from caffeine for a period of months.

01:39:22.920 | Although I confess that after hearing that book,

01:39:25.880 | what it basically made me want to do

01:39:27.120 | is never quit drinking caffeine because it sounded as if,

01:39:29.800 | at least my interpretation was,

01:39:31.060 | that even after several weeks or months

01:39:33.240 | of abstaining from caffeine,

01:39:34.960 | that he still fantasized about the effects of caffeine.

01:39:38.080 | But he did mention that when returning to ingesting caffeine

01:39:41.560 | after a period of long abstinence, that it had almost a,

01:39:45.500 | let's not call it a psychedelic property,

01:39:48.500 | but it had such obvious effects on mood and alertness

01:39:53.420 | and feelings of wellbeing that it really highlighted for him

01:39:56.620 | the extent to which caffeine normally was allowing him

01:39:59.220 | to just function what he thought was normally.

01:40:01.340 | So in other words, many of us don't even really know

01:40:03.900 | what our normal basal level

01:40:05.740 | of cognitive and physical functioning is

01:40:08.300 | because we're ingesting caffeine on such a regular basis.

01:40:10.900 | I confess that as much as I enjoyed that book

01:40:13.260 | and as intriguing as his description of caffeine abstinence

01:40:16.960 | and then the return to caffeine was,

01:40:18.940 | I don't intend to ever find out personally.

01:40:20.960 | Now, a very good reason why you might want to abstain

01:40:23.500 | from caffeine for a deliberate period of time

01:40:25.460 | and then return to caffeine intake

01:40:28.380 | is for its physical performance enhancing effects.

01:40:32.840 | And here we can look to a really interesting study,

01:40:35.700 | title of which is "Time Course of Tolerance

01:40:37.940 | to the Performance Effects of Caffeine."

01:40:39.420 | And what I like about this study

01:40:40.440 | is that while yes, it does say that abstaining from caffeine

01:40:43.760 | and then returning to caffeine intake

01:40:45.580 | can enhance physical performance in a very specific way.

01:40:48.620 | It also says that if you take caffeine regularly,

01:40:50.880 | you can still see the physical performance

01:40:53.160 | enhancing effects of caffeine,

01:40:54.660 | although they are not quite as robust as they would be

01:40:58.020 | had you abstained from caffeine.

01:40:59.700 | The design of the study is pretty straightforward.

01:41:03.920 | They had people either ingest three milligrams

01:41:06.460 | per kilogram of caffeine for 20 consecutive days.

01:41:09.660 | Many people are already doing that, I realize,

01:41:11.460 | but they had people do that

01:41:12.920 | or ensure that they were doing that,

01:41:14.520 | or others ingested a placebo for 20 days.

01:41:17.620 | So they abstained from caffeine without realizing it.

01:41:20.680 | Then after that 20 days of either ingesting caffeine

01:41:25.320 | or a placebo, their peak performance was measured

01:41:30.280 | in terms of aerobic output,

01:41:32.120 | but prior to that measurement, they had caffeine, okay?

01:41:34.700 | So it's 20 days of caffeine and then a 21st day of caffeine

01:41:38.060 | and then the physical task on that 21st day,

01:41:40.760 | or it's 20 days of abstinence from caffeine,

01:41:43.360 | and then on day 21, you get caffeine

01:41:45.320 | and you get the same physical test.

01:41:46.880 | And what they discovered was that the ingestion of caffeine

01:41:51.480 | increased peak performance in this aerobic output

01:41:54.600 | dramatically if people had abstained from caffeine,

01:41:58.780 | but for people that had consumed caffeine

01:42:03.240 | all the way through up until that day,

01:42:05.440 | it still was effective to ingest caffeine on day 21,

01:42:10.020 | but not as effective as it would have been

01:42:12.520 | had they abstained.

01:42:14.160 | And in fact, the magnitude of the,

01:42:17.140 | what they call ergogenic effect,

01:42:19.540 | which is the pro-performance enhancing effect of caffeine,

01:42:22.760 | was higher on the first day than in subsequent days

01:42:26.860 | when they allowed people to continue caffeine intake.

01:42:28.980 | So the takeaway from this study is really straightforward.

01:42:31.260 | If you want to get the maximum physical performance

01:42:33.440 | enhancing effects of caffeine, you abstain from caffeine

01:42:36.660 | for 20 days, then on day 21,

01:42:39.280 | when you're going to do the physical thing, the task,

01:42:42.160 | you ingest caffeine about 30 minutes to an hour

01:42:45.100 | before you do that physical challenge.

01:42:48.560 | Now, 20 days of abstinence is going to be rough

01:42:50.600 | for a lot of people.

01:42:51.440 | I certainly don't want to sign up for this study,

01:42:53.600 | in which case you might want to do five days of abstinence

01:42:56.920 | as we talked about before.

01:42:58.220 | And then on day six is the day that you ingest caffeine

01:43:01.740 | and do the physical task.

01:43:03.760 | There are even some studies showing that you can abstain

01:43:05.580 | from caffeine for just two days, for just 48 hours.

01:43:09.120 | And in particular, if you are a regular user of caffeine,

01:43:13.100 | this allows you to, on day three,

01:43:15.800 | ingest caffeine at the dose that's appropriate for you

01:43:18.720 | and do the physical, or I should mention,

01:43:21.300 | mental performance task and perform significantly better

01:43:24.820 | than those that have been taking caffeine

01:43:27.360 | throughout the entire period leading up to the challenge.

01:43:30.160 | So you don't necessarily need to abstain for 20 days

01:43:33.420 | in order to get the pro-performance effects of caffeine

01:43:35.760 | on day 21.

01:43:36.780 | You could do five days of abstinence prior,

01:43:38.480 | or even two days of abstinence prior.

01:43:40.180 | Or if that's intolerable to you, as it is in my mind to me,

01:43:44.320 | to just reduce your caffeine intake slightly,

01:43:46.880 | or even perhaps have it, if you can tolerate that,

01:43:50.240 | in the week or two weeks, or maybe even three weeks

01:43:53.620 | preceding some physical or mental challenge.

01:43:55.880 | Now, again, this sort of implies

01:43:57.400 | that you're going up against a marathon,

01:43:59.400 | or you're going up against a series of long tests,

01:44:02.520 | maybe standardized tests in one day.

01:44:04.680 | There, I just really want to point out

01:44:06.200 | that there is an abundant literature showing

01:44:08.480 | that people perform best on mental tests

01:44:11.440 | if they are in the state that they were

01:44:14.320 | when they studied for that material.

01:44:17.180 | Now, in college, I knew a number of people

01:44:19.020 | who took this to the extreme,

01:44:20.360 | thinking that if they were to study

01:44:21.960 | under the effects of alcohol,

01:44:23.200 | that they would be best off consuming alcohol

01:44:26.100 | prior to taking exams, and it turns out to not be the case.

01:44:29.160 | Here, we're talking, in particular,

01:44:30.720 | about psychostimulant effects of caffeine

01:44:33.400 | and other compounds.

01:44:34.740 | So don't think that you can drink

01:44:36.880 | or be under the influence of THC when you study,

01:44:40.740 | and then take an exam under the same influence

01:44:42.620 | and do just as well as you would

01:44:43.700 | had you not ingested anything.

01:44:44.740 | Please don't let that be the takeaway.

01:44:46.620 | However, do let it be the takeaway

01:44:49.360 | that caffeine's effects are made more potent

01:44:52.320 | by a brief to not so brief period of abstinence

01:44:55.080 | prior to taking a dosage of caffeine.

01:44:57.640 | And then the final point to make

01:44:59.580 | is that if you are somebody

01:45:00.600 | who is not accustomed to drinking caffeine,

01:45:02.680 | meaning you're hypersensitive to caffeine

01:45:04.320 | or you don't regularly ingest caffeine,

01:45:06.280 | please do not ingest caffeine

01:45:07.960 | on the day of any important mental

01:45:09.920 | or physical challenge or performance,

01:45:11.560 | because what you will find

01:45:12.820 | is that because you are not caffeine adapted,

01:45:15.160 | you will experience changes in your thermal regulation,

01:45:18.320 | in your levels of anxiety and jitteriness,

01:45:20.800 | and your levels of focus that could be very detrimental

01:45:23.800 | to mental or physical performance.

01:45:25.760 | So you don't want to throw yourself in the deep end

01:45:28.480 | by ingesting caffeine if you're not used to it.

01:45:30.600 | And I should mention that for people

01:45:31.600 | that are not accustomed to ingesting caffeine

01:45:34.060 | or are very sensitive to caffeine,

01:45:35.720 | even 25 to 50 milligrams of caffeine

01:45:38.320 | in the amount that's found in, for instance,

01:45:40.440 | a piece of certain types of chocolate

01:45:42.480 | can actually cause anxiety.

01:45:44.120 | So be careful there.

01:45:45.420 | Here I'm referring only to people

01:45:46.680 | that are accustomed with caffeine intake.

01:45:48.940 | So what I recommend is to explore

01:45:51.600 | the ergogenic effects of caffeine during your training,

01:45:54.960 | and then to make a decision about what you can reasonably

01:45:58.260 | and reliably do in terms of abstinence,

01:46:00.180 | and then pulse with caffeine on the day of the challenge.

01:46:04.120 | I get a lot of questions as to whether or not

01:46:05.840 | caffeine has different effects on the nervous system

01:46:07.940 | and on performance in particular,

01:46:09.640 | depending on phases of the menstrual cycle.

01:46:12.480 | So I explored that in my research for this episode,

01:46:14.680 | and I found two studies,

01:46:15.880 | both of which we will reference in the show note captions.

01:46:18.320 | The first one is entitled

01:46:20.680 | Caffeine Consumption and Menstrual Function.

01:46:22.640 | So it's actually the relationship

01:46:23.960 | between caffeine and menstrual function.

01:46:25.540 | We will do an entire episode

01:46:26.760 | about the menstrual cycle and menstrual function.

01:46:29.080 | But the other one, as it relates to performance,

01:46:30.820 | was published in 2020 in the European Journal of Nutrition,

01:46:34.200 | which is ergogenic effects of caffeine

01:46:36.920 | on peak aerobic cycling power during the menstrual cycle.

01:46:39.300 | And the basic takeaway of this study,

01:46:41.340 | this is frankly a very nice study,

01:46:43.840 | showed that quote,

01:46:45.100 | "Caffeine increased peak aerobic cycling power

01:46:48.020 | in the early follicular, pre-ovulatory,

01:46:50.760 | and mid-luteal phases of the menstrual cycle.

01:46:53.740 | Thus the ingestion," and again here,

01:46:55.100 | they use three milligrams of caffeine

01:46:56.660 | per kilogram of body mass,

01:46:58.020 | might be considered an ergogenic aid

01:47:02.360 | for women who are in the menstrual cycle

01:47:05.320 | during all three phases of their cycle.

01:47:07.220 | So keep that in mind, women,

01:47:09.340 | for those of you that are regular users of caffeine,

01:47:11.540 | or you're using caffeine to enhance physical performance,

01:47:14.400 | there does not seem to be

01:47:15.620 | any menstrual cycle phase dependent effects

01:47:18.940 | of caffeine on performance.

01:47:20.200 | That is caffeine seems to always increase physical performance

01:47:24.020 | regardless of the phase of the menstrual cycle

01:47:26.280 | you might happen to be in.

01:47:27.280 | I'd like to touch on a little bit more

01:47:29.200 | of the use of caffeine for enhancing mental performance.

01:47:33.120 | Yes, it is the case that ingesting one to three milligrams

01:47:37.000 | of caffeine per kilogram of body weight

01:47:39.100 | in the 30 minutes or so prior to doing a memory task,

01:47:42.840 | or sitting down to doing some studying,

01:47:45.600 | or learning of any kind,

01:47:47.760 | physical or mental performance of any kind is beneficial

01:47:51.620 | for all the reasons we talked about before

01:47:53.860 | related to dopamine and acetylcholine, et cetera.

01:47:57.080 | But it turns out that it is also the case

01:48:00.280 | that spiking one's adrenaline

01:48:03.320 | and other so-called catecholamines,

01:48:04.880 | so this would be dopamine, norepinephrine and epinephrine,

01:48:07.720 | after about of learning can greatly enhance memory

01:48:12.500 | for the information that one was trying to learn.

01:48:15.440 | That's right.

01:48:16.460 | Spiking your adrenaline after learning

01:48:19.100 | can greatly increase memory

01:48:20.860 | for the material you're trying to learn.

01:48:23.840 | In fact, this is a practice that dates back centuries

01:48:27.220 | and was written about in a beautiful annual review

01:48:29.940 | of neuroscience on the biology of memory by James McGaugh,

01:48:33.660 | where he talks about medieval practices

01:48:35.980 | of children being taught information

01:48:38.480 | and then being thrown literally into cold water

01:48:41.500 | to stimulate the release of adrenaline

01:48:43.580 | and that increase in adrenaline while the mechanism

01:48:47.080 | wasn't completely understood,

01:48:48.480 | it was understood that that sort of shock to the system

01:48:51.680 | from the cold water led to better memory

01:48:55.340 | and retention of the information

01:48:57.640 | that these children had been exposed to.

01:48:59.220 | And it turns out the exact same thing is true for adults

01:49:02.120 | in the laboratory or kids in the laboratory.

01:49:04.140 | And here, I'm not suggesting throwing anyone

01:49:05.960 | into cold water.

01:49:06.800 | If you want to get into cold water,

01:49:08.120 | there's a reason we call it deliberate cold exposure

01:49:10.680 | on the podcast is that it should be deliberate

01:49:12.800 | and controlled by you, not by somebody else.

01:49:15.020 | If it's controlled by somebody else,

01:49:16.160 | that might be military screening or something.

01:49:19.120 | But here we're talking about deliberately increasing

01:49:22.980 | your levels of adrenaline and other catecholamines,

01:49:25.940 | dopamine, norepinephrine, et cetera.

01:49:28.240 | You can do that certainly by deliberate cold exposure

01:49:30.920 | with a cold shower or getting in up to your neck

01:49:34.040 | in cold water of any kind.

01:49:36.360 | But the other way to do that is to spike your adrenaline

01:49:39.500 | by ingesting a one to three milligrams per kilogram

01:49:42.900 | of caffeine after sitting down

01:49:46.380 | to try and learn some material.

01:49:47.860 | I confess that more often than not,

01:49:49.900 | I use caffeine the same way that most people use it,

01:49:52.160 | which is, okay, I'm going to sit down,

01:49:53.700 | I'm going to research information for a podcast

01:49:56.480 | or assemble some information for a paper or grant.

01:50:00.100 | And I want to focus, so I will drink a cup of coffee

01:50:02.700 | at the beginning of that and maybe even throughout that,

01:50:06.580 | or a cup of Yerba Mate at the beginning or throughout that,

01:50:09.060 | or I'll sip on one or both throughout trying to learn.

01:50:13.060 | And that works quite well in terms of maintaining focus

01:50:16.760 | and alertness and retention of information.

01:50:20.520 | But it is indeed the case,

01:50:22.220 | that is the research supports the fact,

01:50:24.120 | and I've experienced the fact that if I abstained

01:50:26.500 | from caffeine while I'm trying to learn something,

01:50:28.940 | but then I drink caffeine immediately after,

01:50:31.100 | somewhat surprisingly to me,

01:50:33.740 | but certainly in a way that's consistent

01:50:36.060 | with the research literature,

01:50:38.660 | memory for the information that I was focused on

01:50:42.240 | prior to ingesting that caffeine is much greater.

01:50:45.020 | And here I'm talking about it as a personal anecdote,

01:50:46.860 | but this is actually what the data point to

01:50:48.420 | both in animals and in humans.

01:50:50.820 | And if you think about it, it makes perfect sense,

01:50:53.020 | because the way that the memory systems

01:50:56.220 | of the brain are organized is that

01:50:58.300 | we go through life experiencing things,

01:51:00.220 | we encounter surprises, both good and bad,

01:51:02.780 | we go through the motions of things,

01:51:05.060 | both typical mundane, exciting and novel and not novel.

01:51:10.060 | And then every once in a while,

01:51:12.660 | something will happen that will spike our catecholamines,

01:51:15.420 | dopamine, typically if it's a positive surprise,

01:51:18.020 | adrenaline, which can be associated

01:51:20.660 | with both positive surprise or positive events

01:51:23.420 | and negative events or surprises.

01:51:26.540 | And without fail, increases in the catecholamines

01:51:31.460 | tend to lock in memories for things that preceded

01:51:35.580 | the increase in those catecholamines.

01:51:37.160 | Again, the catecholamines being dopamine,

01:51:39.100 | epinephrine and norepinephrine,

01:51:40.380 | sometimes all three in combination,

01:51:41.980 | sometimes just two of those,

01:51:43.100 | sometimes just one of those, depending on the experience.

01:51:46.340 | So it makes perfect sense that using caffeine

01:51:49.500 | at the end of a learning bout would enhance our memory

01:51:53.560 | for the information that we're trying to learn.

01:51:55.520 | So if you decide that you want to try and

01:51:57.620 | extract this performance enhancing effect of caffeine,

01:52:00.500 | what I recommend would be to try and abstain from caffeine

01:52:04.900 | for a day or two prior.

01:52:06.060 | But if you can't,

01:52:06.900 | to just continue with your normal caffeine intake.

01:52:09.360 | But then when you sit down to study or learn something

01:52:12.140 | to not ingest any caffeine as you do that,

01:52:15.980 | but then afterward to ingest caffeine.

01:52:18.160 | Now, in theory, you could probably further enhance

01:52:20.500 | the memory encoding effects of adrenaline

01:52:23.300 | and the other catecholamines by drinking caffeine

01:52:25.900 | and then taking a cold shower,

01:52:27.980 | doing deliberate cold exposure

01:52:29.340 | if you really wanted to or had the ability to,

01:52:31.500 | or doing some sort of intense form of exercise.

01:52:34.860 | And we'll talk in a moment about how caffeine exercise

01:52:38.100 | and the adrenaline system interact.

01:52:40.180 | But as a brief, but relevant aside,

01:52:42.800 | brief bouts of intense exercise,

01:52:44.740 | ranging from 10 to 50 minutes or so,

01:52:47.700 | have been shown to improve memory for information

01:52:51.180 | that one was trying to learn prior to the intense exercise.

01:52:54.100 | This is work from Dr. Wendy Suzuki's lab at NYU,

01:52:58.000 | as well as other laboratories.

01:52:59.940 | Some of the work that's being done at Stanford

01:53:02.120 | and the mind-body laboratories

01:53:04.700 | and our laboratory points in the direction

01:53:06.540 | of these kinds of effects as well.

01:53:08.780 | They all come back to the same general neurochemical theme,

01:53:13.040 | which is that when we experience an increase

01:53:15.780 | in these catecholamines that include adrenaline,

01:53:18.780 | dopamine and norepinephrine,

01:53:21.060 | the memory systems of the brain flip on

01:53:23.840 | in a way that try to capture the information

01:53:27.140 | and the perceptions and the experiences

01:53:29.460 | that we were exposed to just prior

01:53:31.720 | to the increase in catecholamines.

01:53:33.620 | And caffeine, but also exercise and also cold water,

01:53:37.400 | and of course, any of those alone or in combination,

01:53:41.300 | all increase the levels of catecholamines.

01:53:43.400 | So it makes perfect logical mechanistic sense

01:53:46.200 | as to why this would work, and in fact, it does work.

01:53:48.780 | If you want to remember specific information,

01:53:51.400 | you might consider using caffeine

01:53:52.920 | as you move through and absorb

01:53:54.560 | and are exposed to that information,

01:53:56.220 | but you might also consider using caffeine

01:53:59.500 | after being exposed to that information,

01:54:01.400 | because studies in animals and humans show

01:54:03.760 | that that is a potent way to increase memory

01:54:06.480 | for what you were just exposed to.

01:54:08.320 | I should mention that what I just described

01:54:10.000 | also pushes back on something

01:54:11.760 | that I know a number of people perhaps have heard about

01:54:14.600 | and maybe even use, which is this notion of the nappuccino.

01:54:17.740 | I remember hearing about this a few years back.

01:54:19.300 | It was a sort of trend, if you will.

01:54:22.880 | The trend involved drinking a cup of coffee

01:54:25.200 | or double espresso and then going down for a nap,

01:54:27.900 | typically in the afternoon, and then waking up,

01:54:29.740 | and the idea was that the caffeine would hit your system

01:54:32.160 | right at the time that you awake from the nap

01:54:34.000 | and that you would be better able to focus and exercise.

01:54:36.880 | There are a couple of things about that practice

01:54:40.280 | that I don't like.

01:54:41.240 | First of all, it implies in most cases

01:54:44.600 | that you're napping and ingesting caffeine in the afternoon,

01:54:48.480 | which I realize for many students

01:54:51.520 | and for people that are comfortable staying up

01:54:52.920 | until the wee hours of the night

01:54:54.400 | and then waking up late the next day

01:54:56.500 | might be compatible with their schedule.

01:54:59.000 | But again, because of the sleep diminishing effects

01:55:02.500 | of caffeine, and we talked about earlier,

01:55:05.460 | I'm not crazy about the idea of people ingesting caffeine

01:55:08.040 | in the late afternoon

01:55:09.080 | in order to perform better in the late afternoon.

01:55:12.040 | Far better would be to restrict caffeine intake

01:55:14.020 | to the early part of the day, as we talked about earlier.

01:55:16.460 | The other reason is that the data

01:55:19.360 | on things like non-sleep deep rest

01:55:22.360 | and naps in the afternoon.

01:55:25.020 | And again, the rule here is that you don't have to nap,

01:55:27.440 | but if you want to nap,

01:55:28.560 | it's been shown that naps of 90 minutes or less

01:55:31.440 | or non-sleep deep rest protocols,

01:55:33.400 | and you can find those, for instance,

01:55:34.440 | there's one with me speaking,

01:55:35.840 | you just put NSDR Huberman into YouTube.

01:55:38.480 | You can hear that it's completely zero cost.

01:55:40.180 | There are other NSDR scripts out there now, of course,

01:55:42.440 | if you prefer those,

01:55:44.120 | that those can all lead to increases

01:55:46.560 | in one of the catecholamines at least, which is dopamine.

01:55:50.820 | That's been shown in a really nice

01:55:54.300 | neurotransmitter labeling study,

01:55:55.780 | not from my laboratory, but from another laboratory,

01:55:57.960 | but also can improve mood focus and alertness on its own

01:56:01.460 | without the need to ingest caffeine

01:56:03.340 | prior to going into those states.

01:56:05.260 | And in fact, ingesting caffeine prior to a nap

01:56:07.820 | or ingesting caffeine prior to NSDR

01:56:10.420 | is most certainly going to reduce the effectiveness

01:56:14.200 | of that nap and NSDR in restoring natural levels

01:56:17.340 | of alertness and focus

01:56:18.620 | that would lead to the performance enhancing effect.

01:56:20.320 | So I'm not such a fan of the so-called nappuccino,

01:56:22.840 | although if any of you out there

01:56:24.220 | have derived great benefit from it,

01:56:25.980 | definitely let me know your protocol

01:56:27.740 | and what you've experienced.

01:56:28.760 | Put it in the comment section, if you would.

01:56:31.800 | I'd appreciate that.

01:56:33.060 | There's another very important and potent use of caffeine

01:56:36.040 | for enhancing performance.

01:56:37.480 | And this relates not just to the dopamine and epinephrine

01:56:42.260 | and the arousal inducing effects of caffeine.

01:56:45.840 | And it doesn't even just relate to the effect of caffeine

01:56:50.060 | on enhancing frontal lobe function.

01:56:51.640 | It does include all that,

01:56:53.040 | but it also includes those reinforcing effects of caffeine

01:56:56.820 | that we talked about at the beginning of the episode.

01:56:59.960 | And the best way to illustrate

01:57:01.880 | these performance enhancing effects of caffeine

01:57:04.320 | that stem directly from its association with reinforcement

01:57:09.020 | is to highlight a study.

01:57:10.460 | And the title of the study is a blood dopamine level

01:57:13.040 | enhanced by caffeine in men after treadmill running.

01:57:16.440 | And as the title suggests, this was carried out in men,

01:57:19.100 | but there's no reason to think that the same results

01:57:22.040 | wouldn't also be present in women.

01:57:24.240 | There are some sex dependent effects of caffeine.

01:57:26.540 | I'll touch on just briefly at the end,

01:57:28.300 | but those are largely present in kids,

01:57:31.480 | that is adolescents and teens, as opposed to adults.

01:57:35.120 | So this study is really interesting.

01:57:36.920 | What they had people do was run on a treadmill

01:57:39.820 | and either ingest caffeine, again,

01:57:42.520 | three milligrams per kilogram of body weight,

01:57:45.560 | or to not ingest caffeine.

01:57:47.760 | And then they looked at levels of dopamine

01:57:50.640 | and other neurotransmitters and hormones

01:57:53.240 | such as prolactin and cortisol.

01:57:55.380 | And the basic takeaway is, as the title suggests,

01:57:58.400 | that exercise while on its own can increase cortisol

01:58:02.380 | in healthy ways provided it's not too intense and too long.

01:58:06.040 | Little note here, if you have trouble recovering

01:58:09.000 | from exercise, or you want to continue to derive

01:58:11.040 | the benefits from exercise, in general,

01:58:13.960 | best not to do high intensity exercise

01:58:16.020 | for longer than 75 minutes or 90 minutes,

01:58:19.380 | I'll be in the outer threshold.

01:58:20.580 | I realize that there are some genetic freaks out there

01:58:22.620 | or people that are chemically assisted

01:58:23.940 | that can recover from very intense long bouts of exercise,

01:58:27.560 | but most people don't do well,

01:58:30.760 | long bouts of intense exercise on a regular basis

01:58:33.480 | and limiting their intense exercise to 60 minutes or less,

01:58:38.100 | that doesn't include the warmup, is going to be beneficial.

01:58:40.220 | See the episode on a toolkit for fitness

01:58:43.060 | if you'd like details on that.

01:58:45.420 | Exercise is known to increase levels of dopamine, cortisol,

01:58:49.540 | and other catecholamines and neurotransmitters very potently

01:58:53.760 | and things like testosterone and estrogen

01:58:55.680 | in ways that we know are beneficial to us.

01:58:57.080 | And of course have all these positive effects

01:58:59.040 | on the musculoskeletal system and cardiovascular effects.

01:59:02.280 | But unbeknownst to most people,

01:59:05.240 | ingesting three milligrams per kilogram of caffeine

01:59:08.680 | prior to exercise further increases the dopamine release

01:59:12.680 | associated with exercise specifically.

01:59:15.440 | And this has two important effects.

01:59:17.260 | First of all, that increase in dopamine is great

01:59:19.880 | because it provides a long lasting increase

01:59:22.840 | in focus alertness and motivation,

01:59:24.760 | not just during the exercise, but also after the exercise.

01:59:28.880 | And second, it, that is caffeine and dopamine in combination

01:59:33.880 | act as a reinforcer to make the experience of exercise

01:59:38.880 | and the period immediate after exercise

01:59:41.880 | more pleasant and in fact reinforcing.

01:59:44.360 | So in other words, one way to enjoy exercise more

01:59:48.900 | and to enjoy the activities that follow exercise more

01:59:51.960 | and to experience a genuine increase in dopamine

01:59:55.320 | that's beneficial for mood and alertness

01:59:58.080 | is to ingest caffeine prior to exercise.

02:00:02.200 | Now, this is important because a number of people out there

02:00:05.760 | are exercising, love exercise, love eating great,

02:00:09.900 | love doing all the things that are beneficial

02:00:11.380 | for their health, but a number of people out there

02:00:13.500 | really don't like to exercise.

02:00:15.380 | And that serves as a serious block for their willingness

02:00:20.020 | and their consistency to exercise.

02:00:22.160 | Ingesting caffeine gives us energy to exercise.

02:00:28.200 | It increases the release of neurochemicals and hormones

02:00:31.480 | that are good for us during exercise.

02:00:33.460 | But as I'm highlighting here,

02:00:35.600 | it also increases the reinforcement pathways

02:00:39.600 | associated with exercise.

02:00:41.840 | That is, it creates a positive feeling

02:00:44.800 | about the general theme of engaging in exercise

02:00:48.280 | and it creates a general positive experience

02:00:51.460 | of the things that follow exercise.

02:00:53.580 | So I think this, if nothing else is a call for

02:00:57.700 | or support for the idea that ingesting caffeine

02:01:00.420 | as a performance enhancing tool makes perfect sense.

02:01:03.460 | But for those out there that don't enjoy exercise,

02:01:06.140 | in particular, certain forms of exercise,

02:01:08.580 | ingesting caffeine can change your relationship

02:01:11.840 | to that exercise.

02:01:13.260 | In other words, make it more positive.

02:01:14.740 | Much in the same way that ingesting caffeine

02:01:17.920 | alongside a certain taste that would otherwise be neutral

02:01:20.760 | or maybe even negative can actually make the taste

02:01:23.440 | of that particular drink or food positive.

02:01:25.780 | So again, this brings us back to the reinforcing properties

02:01:28.340 | of caffeine that are subconscious.

02:01:30.640 | It's not just about the enhanced performance in the test

02:01:34.300 | or the enhanced performance on the treadmill

02:01:36.620 | or with the weights in the gym.

02:01:38.580 | It's enhanced feelings of mood and wellbeing

02:01:40.540 | that are genuine because of the effect of caffeine

02:01:43.180 | on certain neurotransmitter and hormone systems.

02:01:45.900 | But it also is creating an overall milieu

02:01:48.820 | of reinforcing all of the things that led into

02:01:51.980 | occur during and occur after exercise.

02:01:55.460 | I do want to point out something that's very important

02:01:57.560 | as it relates to combining things like caffeine

02:02:01.700 | and exercise in order to increase dopamine.

02:02:03.980 | This is something that came up in the episode

02:02:05.780 | that I did on dopamine motivation and drive,

02:02:08.340 | which turns out to be one of our most popular episodes.

02:02:11.140 | Again, you can find that at hubermanlab.com

02:02:13.340 | and links to all formats with timestamps, et cetera.

02:02:15.780 | This also came up in the episode on ADHD

02:02:18.920 | because of the relationship between ADHD and dopamine.

02:02:21.540 | And that's this notion of dopamine stacking.

02:02:24.620 | In the episode on dopamine motivation and drive,

02:02:27.900 | I pointed out that while there are a near infinite number

02:02:31.060 | of things that can increase dopamine release,

02:02:34.020 | most notably positive surprise or positive anticipation

02:02:39.020 | or experiencing a win, certainly there are compounds,

02:02:42.980 | both drugs of abuse, food, sex, and certain supplements

02:02:47.720 | that can increase dopamine to varying levels

02:02:49.700 | and to varying degrees, both healthy and unhealthy.

02:02:52.840 | That's all contained in that episode

02:02:54.120 | on dopamine motivation and drive.

02:02:55.940 | But what I pointed out is that if you are somebody

02:02:58.240 | who tends to experience difficulty with motivation,

02:03:02.140 | that so-called dopamine stacking, as I called it,

02:03:05.120 | might be something that you want to avoid.

02:03:06.600 | What is dopamine stacking?

02:03:07.660 | Dopamine stacking would be combining a highly caffeinated

02:03:12.060 | energy drink that also includes the amino acid tyrosine,

02:03:15.460 | which is a precursor to dopamine, plus loud music,

02:03:18.260 | plus getting yourself really ramped up

02:03:19.700 | then in an intense workout.

02:03:21.220 | All of that can be great if you do it every once in a while.

02:03:24.860 | But what you will quickly find is that the extent

02:03:27.860 | to which your dopamine peaks also dictates

02:03:31.580 | the extent to which your dopamine will drop after that peak.

02:03:34.660 | And when I say drop, I mean drop below baseline.

02:03:37.000 | So a lot of people find that if they stack a lot of things

02:03:39.100 | to peak their dopamine, then they experience a low,

02:03:42.900 | and it does take some time for them to return to baseline.

02:03:45.780 | And I highly recommend not engaging in activities

02:03:49.520 | or consuming compounds that are in attempt

02:03:53.340 | to accelerate that return to baseline,

02:03:54.980 | because all it will do is drive that baseline

02:03:57.140 | lower and lower.

02:03:58.540 | So this requires being able to tolerate a drop

02:04:00.540 | in dopamine baseline for a period of time, et cetera.

02:04:03.180 | Now, the reason I'm bringing this up now

02:04:04.540 | in the context of this caffeine episode

02:04:06.300 | is I just described a study in which using caffeine prior

02:04:09.760 | to exercise increases dopamine after exercise.

02:04:12.420 | And so you might be saying,

02:04:14.540 | especially if you heard that earlier episode,

02:04:16.000 | wait, isn't that dopamine stacking?

02:04:18.020 | Aren't you encouraging me to stack my dopamine?

02:04:20.580 | Well, in some sense, yes, but keep in mind,

02:04:22.820 | I'm not suggesting that you do this every time you exercise.

02:04:25.460 | So just as in that earlier episode,

02:04:27.300 | I emphasized the fact that while stacking multiple stimuli,

02:04:31.940 | right, caffeine or energy drinks and music and et cetera,

02:04:35.220 | for exercise or for mental work,

02:04:38.300 | or for any experience for that matter,

02:04:40.200 | is okay to do every once in a while for most people,

02:04:42.540 | you don't want to get in the habit of doing it consistently

02:04:45.280 | every time you exercise or every time you go out,

02:04:48.780 | for instance.

02:04:49.620 | And so you really want to be cautious.

02:04:51.540 | That is, you want to protect your both baseline levels

02:04:53.820 | of dopamine and your peak levels of dopamine.

02:04:57.080 | That said, for people that want to experience

02:04:59.300 | an increase in mood alertness and performance,

02:05:01.620 | or who want to condition themselves,

02:05:03.340 | because that's really what it is,

02:05:04.460 | it's conditioning yourself by the reinforcing effects

02:05:06.940 | of dopamine to increase your liking,

02:05:11.940 | or maybe even your loving of exercise,

02:05:14.360 | occasionally using caffeine or frequently using caffeine

02:05:18.000 | prior to exercise is fine, but be very careful.

02:05:21.240 | And by being very careful, what I mean is pay attention

02:05:23.780 | to how you feel in the hours and days after

02:05:27.000 | that dopamine increase wears off.

02:05:29.740 | So for instance, if you ingest caffeine

02:05:32.520 | and then exercise very intensely

02:05:34.760 | and you're feeling great afterwards,

02:05:36.220 | but then eight hours later or the next day,

02:05:38.540 | you're feeling a little bit low,

02:05:40.180 | I suggest you don't go back

02:05:41.300 | and do the exact same thing right away.

02:05:42.780 | I would give you yourself a little bit of time

02:05:44.700 | to let that baseline of dopamine return to normal.

02:05:48.180 | So again, stacking different things, chemical and behavioral

02:05:52.140 | in order to increase dopamine can be done in a safe way

02:05:55.040 | that's beneficial to you depending on your goals,

02:05:57.300 | but be careful about not stacking too many stimuli

02:06:01.000 | for dopamine too often, that's the key.

02:06:03.800 | Early in the episode, I mentioned one possible

02:06:06.860 | caffeine consuming schedule that works very well

02:06:10.100 | that doesn't fortunately subject you to long 20 day bouts

02:06:14.600 | or five day or even two day bouts of abstinence.

02:06:17.100 | And that's the every other day schedule of caffeine.

02:06:20.300 | If you look at the half-life of caffeine

02:06:22.860 | and you look at its effects on the dopamine system

02:06:26.060 | and its performance enhancing effects

02:06:28.340 | and how a period of abstinence can in fact

02:06:31.140 | increase the performance enhancing effects of caffeine,

02:06:33.340 | but also take into consideration

02:06:35.340 | that caffeine can be habit forming

02:06:37.300 | and we can develop a sort of tolerance to caffeine.

02:06:40.460 | Well, then what emerges from all of that

02:06:43.060 | is that being a person who consumes caffeine every other day

02:06:48.280 | can actually help you maximize

02:06:50.420 | most of the positive effects of caffeine

02:06:52.460 | without subjecting you to the kind of misery that occurs

02:06:55.240 | if you're accustomed to consuming caffeine every single day

02:06:58.200 | and then suddenly go into a two or five or 20 day abstinence.

02:07:02.200 | So I myself have never tried

02:07:03.660 | an every other day caffeine approach,

02:07:06.320 | although I'm considering doing it

02:07:08.260 | based on the literature that I've read.

02:07:10.260 | And I'm considering doing it in a very specific way,

02:07:12.360 | which will be to only consume caffeine

02:07:14.340 | on the days in which I resistance train.

02:07:15.980 | And since I tend to do that about three or four days per week

02:07:18.480 | organized in a way that's every other day.

02:07:20.020 | Again, if you want to see the exercise schedule

02:07:21.980 | that I follow, including cardiovascular exercise

02:07:24.100 | and weight training and all the reasons

02:07:26.260 | and rationale for what I do

02:07:28.060 | and how it maps onto the scientific literature

02:07:31.100 | related to health span and life span, vitality, et cetera,

02:07:33.800 | you can find that at Hubermanlab.com.

02:07:35.740 | And we had a toolkit for fitness

02:07:37.400 | that ought to be posted to our website before long.

02:07:40.880 | The every other day schedule of caffeine intake

02:07:43.140 | to me seems like the most rational one

02:07:45.400 | if one wants to maximize

02:07:47.220 | on the performance enhancing effects of caffeine

02:07:49.260 | without suffering the effects of caffeine withdrawal

02:07:52.860 | that are associated with being a regular consumer of caffeine

02:07:56.040 | and then stopping caffeine intake

02:07:57.620 | such as headache and irritability and so forth.

02:08:00.500 | Not I nor anyone in my life

02:08:02.100 | wants me to experience those effects.

02:08:03.740 | And I'm sure you don't want to experience

02:08:05.260 | those effects for you either.

02:08:06.920 | So if you're somebody that decides

02:08:08.160 | to try the every other day protocol,

02:08:10.500 | or you are somebody who's already doing that protocol,

02:08:13.260 | please let me know what your experiences with that are.

02:08:16.580 | At least by my read of the literature on caffeine

02:08:18.900 | and its performance enhancing effects,

02:08:20.340 | but also the effects of caffeine

02:08:22.140 | on neurotransmitter and hormone systems,

02:08:24.800 | the every other day caffeine's schedule

02:08:26.940 | does seem to be the most rational

02:08:28.980 | and scientifically grounded one

02:08:30.740 | in order to maximize on all those effects.

02:08:32.980 | In addition to so-called

02:08:34.000 | performance enhancing effects of caffeine,

02:08:36.060 | there are also the well-studied

02:08:38.380 | and now fairly well mechanistically understood

02:08:42.220 | pro-health effects of caffeine.

02:08:43.980 | Now here when I talk about pro-health effects of caffeine,

02:08:47.780 | I want to be very clear

02:08:49.340 | that if your schedule of caffeine intake,

02:08:52.820 | that is your timing of caffeine intake

02:08:54.580 | or anything else for that matter,

02:08:57.220 | offsets getting regular high quality sleep

02:09:01.020 | of sufficient duration,

02:09:02.340 | well then you are undermining

02:09:03.480 | the pro-health effects of that thing.

02:09:05.360 | This is true for exercise, this is true for caffeine,

02:09:07.540 | this is true for supplementation,

02:09:08.740 | this is true for prescription drugs.

02:09:10.940 | Again, you don't want to be neurotically attached

02:09:12.900 | to the idea that you have to get perfect sleep every night

02:09:14.780 | because that's simply not true,

02:09:16.600 | but it is absolutely the case that anything,

02:09:19.000 | whether or not it's good for you or bad for you

02:09:20.820 | in the short term, that disrupts your sleep

02:09:24.680 | because of the timing in which you're doing that thing

02:09:27.500 | is going to undermine your immediate

02:09:29.500 | and long-term health before long.

02:09:31.600 | So with that said,

02:09:33.300 | there are several well-described

02:09:35.820 | health promoting effects of caffeine ingestion.

02:09:39.060 | And once again, when I say caffeine ingestion,

02:09:42.140 | I'm referring to that one to three milligrams per kilogram

02:09:44.420 | of body weight dosage.

02:09:45.780 | There are really nice studies showing

02:09:48.300 | that being a regular consumer of caffeine

02:09:51.140 | can help offset some of the probability,

02:09:54.560 | some of the probability of developing Parkinson's

02:09:57.640 | and maybe Alzheimer's related dementia as well.

02:10:00.800 | These are not terribly controversial data

02:10:02.900 | because of the fact that caffeine is known

02:10:04.880 | to increase the release of those catecholamines,

02:10:07.860 | dopamine epinephrine and norepinephrine,

02:10:09.720 | as well as acetylcholine.

02:10:11.740 | All those neurotransmitter and neuromodulator systems

02:10:14.320 | are the ones that are known to be defective

02:10:17.860 | in Parkinson's and Alzheimer's,

02:10:19.240 | although there are other transmitter and hormone systems

02:10:21.900 | that are defective as well.

02:10:23.620 | There are beautiful reviews on the neuroprotective effects

02:10:26.540 | of caffeine and neurodegenerative diseases.

02:10:29.200 | They're quite extensive and I'll just refer you to one

02:10:32.140 | and the references they're in,

02:10:33.400 | and we'll provide a link to this in the show note captions.

02:10:35.300 | The title as the topic at hand suggests

02:10:39.320 | is the neuroprotective effects of caffeine

02:10:41.040 | and neurodegenerative diseases.

02:10:42.640 | This was published in 2016.

02:10:44.500 | I'm sure there've been other reviews since then,

02:10:46.780 | but it includes many, many quality references

02:10:49.500 | and studies, both in animals and in humans,

02:10:51.200 | pointing to the fact that specific enzymes

02:10:54.020 | that are associated with the health

02:10:55.780 | of in particular dopamine neurons are made more robust

02:10:59.620 | by regular ingestion of caffeine.

02:11:02.060 | It also points to the fact that the increase

02:11:04.900 | in dopamine receptors that is induced

02:11:07.460 | by regular ingestion of caffeine that I referred to earlier

02:11:11.080 | is another way in which dopamine,

02:11:13.380 | however many dopamine neurons remain around

02:11:15.820 | in people with Parkinson's or people who are aging

02:11:18.020 | that lose dopamine neurons naturally,

02:11:20.280 | that dopamine can have its maximal effect

02:11:23.520 | because of the increase in receptors for dopamine

02:11:26.020 | that caffeine induces.

02:11:28.020 | And there are other biological mechanisms

02:11:30.560 | that further support why caffeine

02:11:33.040 | ought to be neuroprotective,

02:11:35.340 | including its effects on the acetylcholine system,

02:11:37.720 | which is one of the major systems disrupted

02:11:40.340 | in Alzheimer's dementia.

02:11:42.160 | So in other words, it makes perfect sense

02:11:43.540 | as to why caffeine would be neuroprotective.

02:11:46.000 | Caffeine has also been shown to diminish headache,

02:11:48.740 | particularly when taken in combination with aspirin,

02:11:50.960 | and that's because of the effects of caffeine

02:11:52.780 | and aspirin on blood flow.

02:11:54.180 | There's also evidence that caffeine can provide brief

02:11:57.100 | but substantial relief from asthma.

02:11:59.460 | So I wouldn't want people to rely on caffeine

02:12:01.440 | as a life-saving approach to an asthmatic attack.

02:12:06.440 | That said, for people that suffer from minor asthma,

02:12:09.380 | that caffeine intake, again,

02:12:11.220 | of the dosages that we talked about before,

02:12:12.860 | has been shown to alleviate some of the major symptoms

02:12:16.060 | of asthma for anywhere from one to four hours.

02:12:18.300 | And I know this is of relevance

02:12:21.260 | to a lot of people out there,

02:12:22.720 | because caffeine increases the catecholamines,

02:12:26.640 | and in particular,

02:12:27.480 | because caffeine increases dopamine transmission

02:12:30.540 | in the prefrontal cortex,

02:12:32.080 | this area of the brain associated with focus

02:12:34.380 | and rule setting and context and task switching,

02:12:37.860 | caffeine is known to improve focus and alertness,

02:12:42.080 | in particular, in people who have symptoms of ADHD

02:12:46.380 | or other attention and focus issues.

02:12:50.140 | Now, caffeine alone does not appear to be as potent

02:12:54.060 | for the treatment of ADHD as are things like Ritalin,

02:12:57.520 | Adderall, modafinil, and armodafinil, and Vyvanse.

02:13:01.560 | If you would like a sort of head by head comparison

02:13:04.460 | of prescription drugs, supplements, and things like caffeine,

02:13:09.460 | as well as coverage of behavioral tools

02:13:12.840 | and nutritional tools, et cetera,

02:13:14.860 | that can positively offset some of the symptoms of ADHD,

02:13:19.060 | please see the episode that I did on ADHD.

02:13:20.940 | Again, that's available at hubermanlab.com in all formats.

02:13:23.940 | But that said, caffeine does increase focus,

02:13:26.340 | and it does it through a number of different mechanisms,

02:13:28.060 | not the least of which is to increase dopamine transmission

02:13:30.800 | in the forebrain, just as a drug like Ritalin or Adderall

02:13:33.720 | would, although not to the same extent

02:13:36.220 | as a drug like Ritalin or Adderall does.

02:13:38.620 | Before we close today, I do want to just briefly return

02:13:41.720 | to the reinforcing effects of caffeine

02:13:43.840 | that we talked about earlier.

02:13:45.580 | This study on the honeybees that showed that

02:13:47.420 | bees prefer certain nectars because they contain caffeine,

02:13:50.300 | even though they are not aware

02:13:51.820 | that those nectars contain caffeine.

02:13:53.780 | They just come to like the feeling

02:13:55.380 | that those nectars provide them so much

02:13:57.780 | that they associate that in a subconscious way

02:14:01.200 | with the flowers themselves,

02:14:02.460 | and they come to like those flowers.

02:14:03.580 | Or human beings, for instance,

02:14:05.900 | children that ingest caffeinated beverages

02:14:08.260 | come to adore the taste of those beverages.

02:14:11.540 | And beautiful studies have been done

02:14:13.720 | that describe how children and adults

02:14:16.920 | truly cannot distinguish between the taste

02:14:19.060 | of a caffeinated and non-caffeinated beverage.

02:14:22.340 | And caffeine can be placed into essentially any beverage

02:14:25.700 | in order to give us a preference for that beverage or food.

02:14:29.200 | In fact, the studies have been done with yogurt.

02:14:31.400 | If you put caffeine into yogurt of different flavors,

02:14:34.980 | even plain yogurt, which most kids don't like,

02:14:39.460 | they will come to prefer whatever flavor

02:14:42.620 | contain the caffeine,

02:14:44.320 | even if then you remove the caffeine from that flavor.

02:14:47.080 | Now, eventually their preference for that flavor

02:14:48.980 | will be extinguished.

02:14:50.300 | But all of this is just to say

02:14:52.340 | that so many of the things that we like,

02:14:54.220 | whether or not it's coffee or tea,

02:14:56.380 | or a given flavor of food, or a given experience,

02:14:59.600 | or even exercise,

02:15:00.900 | occur because we ingest caffeine

02:15:03.820 | in conjunction with those activities.

02:15:06.700 | Now, these are not tricks

02:15:08.220 | that your nervous system plays on you.

02:15:09.460 | These are real neurochemical reinforcing effects.

02:15:12.540 | And I think that we would all do well

02:15:14.780 | to think about and to leverage these reinforcing effects,

02:15:18.040 | much in the same way we would do well

02:15:19.620 | to think about and hopefully not leverage

02:15:22.980 | aversive effects of certain compounds, right?

02:15:25.340 | The simple way to put this is,

02:15:27.060 | I or anyone could get you to dislike something,

02:15:30.180 | someone, or someplace

02:15:32.280 | by making you feel slightly less good, lower mood.

02:15:36.740 | I don't even have to make you feel nauseous,

02:15:38.060 | but less good after ingesting something

02:15:41.420 | or having a certain kind of interaction

02:15:43.460 | or being in a certain environment.

02:15:45.220 | Very straightforward to do that

02:15:46.940 | because of the way that your nervous system

02:15:48.300 | is wired for conditioning.

02:15:49.680 | However, there's the positive side of all this,

02:15:52.780 | which is that it's very straightforward

02:15:54.540 | to reinforce the experience of a given food,

02:15:58.060 | including its taste, but all the context around it,

02:15:59.980 | the container, the texture,

02:16:01.700 | the people you consume it with,

02:16:02.780 | where you consume it, et cetera.

02:16:04.480 | For instance, I wonder why we are not pairing caffeine

02:16:09.980 | with broccoli.

02:16:11.860 | And here, I'm not suggesting

02:16:13.060 | that people actually do that experiment

02:16:15.020 | or play that trick on people.

02:16:18.040 | But you have to sort of imagine

02:16:20.560 | that if caffeine is this incredible reinforcer

02:16:23.700 | of all sorts of things,

02:16:25.160 | in particular things that we ingest

02:16:26.900 | and would want to ingest more of

02:16:28.840 | if it's paired with caffeine,

02:16:30.680 | well, then you actually can use caffeine as a tool

02:16:33.500 | to increase reinforcement of different things.

02:16:35.820 | And you can avoid caffeine

02:16:38.320 | as a way to further reinforce things

02:16:41.280 | that you would like to stop.

02:16:42.340 | And here, I'd like to just give the example

02:16:43.860 | of sugar cravings.

02:16:44.940 | A lot of people ask me, "How do I avoid sugar cravings?"

02:16:47.260 | I've talked about the use of L-glutamine for that.

02:16:49.540 | I've talked about making sure

02:16:50.440 | you're getting enough essential fatty acids

02:16:52.760 | and essential amino acids

02:16:54.200 | as a way to reduce sugar cravings.

02:16:56.840 | Please note, however, that if you are somebody

02:17:00.140 | who likes to have your sugar,

02:17:02.380 | whether or not it's a piece of chocolate

02:17:03.680 | or your dessert, et cetera,

02:17:04.740 | I'm not saying that's bad,

02:17:05.860 | but if you're trying to reduce your sugar cravings,

02:17:08.700 | ask yourself, are you ingesting sugar along with caffeine?

02:17:12.360 | Could be the caffeine contained

02:17:13.500 | in that sugar containing food like chocolate,

02:17:15.480 | or it could be that you're having a cup of coffee

02:17:17.400 | along with your pastry,

02:17:18.340 | and then you're struggling with sugar cravings.

02:17:20.660 | Well, think about it.

02:17:21.500 | You're not just being reinforced by the sugar

02:17:23.620 | and the effects of sugar on dopamine,

02:17:24.960 | which are real and both conscious and subconscious

02:17:27.800 | through the gut to the brain dopamine system

02:17:29.600 | and direct on the brain dopamine system.

02:17:32.140 | But by co-ingesting caffeine,

02:17:34.360 | you are also further enhancing

02:17:36.000 | the reinforcing effects of sugar.

02:17:38.300 | The flip side to all of this is that you could use caffeine

02:17:42.240 | as a way to increase your appetite for certain things.

02:17:45.120 | I actually know somebody,

02:17:46.080 | I won't reveal who this person is,

02:17:47.540 | but they are quite prominent podcaster

02:17:49.840 | who ingests 125 to 150 milligrams of caffeine

02:17:54.040 | in tablet form, in tablet form,

02:17:56.580 | along with herbal tea,

02:17:58.200 | and use this as a way to develop a preference for herbal tea

02:18:02.060 | because they found that coffee

02:18:04.580 | was giving them other effects that weren't good for them.

02:18:07.280 | So it works quite well in animals,

02:18:09.300 | and it works quite well in insects,

02:18:10.840 | and it works quite well in humans.

02:18:13.040 | I suppose animals, insects, and humans are all animals

02:18:15.360 | at the end of the day, so no surprise there.

02:18:17.380 | But it all underscores the sense to which caffeine

02:18:20.880 | is an absolutely fascinating molecule.

02:18:23.200 | I mean, it's an ability to offset the sleepiness system,

02:18:26.900 | if you will, this adenosine system,

02:18:28.480 | and to control our schedules in that way,

02:18:30.420 | to essentially take a withdrawal against the bank

02:18:33.000 | that is adenosine and then pay that back later

02:18:35.160 | in the form of getting sleepy later

02:18:36.840 | as opposed to when we want to be alert.

02:18:38.880 | Its ability to enhance focus, alertness, and mood,

02:18:42.080 | and if taken after, trying to learn something

02:18:44.240 | and remember it to enhance memory especially,

02:18:47.940 | and its ability to increase VO2 max, increase strength.

02:18:51.480 | We didn't even talk today about it,

02:18:52.680 | but I'll just briefly mention that caffeine ingested

02:18:55.960 | in the sorts of doses we talked about earlier

02:18:57.960 | because its effects on the neuromuscular system

02:19:00.240 | and the calcium system associated with neuromuscular

02:19:04.400 | exertion and fatigue can increase peak power output

02:19:07.780 | and muscle contractibility.

02:19:10.200 | It's enhancing performance there as well.

02:19:12.340 | And of course, caffeine does a number of other things

02:19:14.960 | just generally related to our overall and basal level

02:19:17.800 | of mood and alertness,

02:19:19.040 | not the least of which are these increases in dopamine.

02:19:21.920 | So caffeine is really an incredible molecule.

02:19:24.580 | It's affecting all these various neurotransmitter systems,

02:19:27.400 | but not haphazardly.

02:19:29.000 | It's increasing dopamine and acetylcholine in the forebrain

02:19:32.780 | to increase attention.

02:19:33.620 | It's reducing fatigue.

02:19:34.700 | It's improving mental and physical performance

02:19:37.020 | for some obvious and some not so obvious reasons.

02:19:39.200 | And what I think is among the more miraculous

02:19:41.980 | and powerful effects of caffeine,

02:19:43.360 | it is a potent, potent, potent reinforcer

02:19:47.380 | of things, foods, people, and experiences.

02:19:51.440 | And it's one that you can leverage

02:19:53.160 | in any direction that you like

02:19:54.620 | once you understand the way that caffeine

02:19:57.240 | exerts those reinforcing properties.

02:19:59.540 | So today I've really tried to cover as much as I could

02:20:02.400 | about the mechanisms of caffeine action

02:20:04.240 | in the brain and body,

02:20:05.240 | as well as tools and schedules and dosages

02:20:08.240 | in which you can leverage caffeine

02:20:10.240 | in order to meet your physical performance,

02:20:12.640 | mental performance, and frankly,

02:20:14.500 | mental health and overall health goals.

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02:21:07.760 | During today's episode and on many previous episodes

02:21:10.040 | of the Huberman Lab Podcast, we discussed supplements.

02:21:12.860 | While supplements aren't necessary for everybody,

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02:22:12.660 | deliberate cold exposure, and so on.

02:22:14.720 | By going to HubermanLab.com, going to the menu,

02:22:17.080 | going to newsletter,

02:22:18.060 | and there you'll see those as immediately downloadable PDFs.

02:22:21.100 | Thank you for joining me for today's discussion

02:22:22.840 | about caffeine, both its mechanisms

02:22:24.600 | and its many powerful uses.

02:22:26.600 | And last, but certainly not least,

02:22:28.960 | thank you for your interest in science.

02:22:30.760 | (upbeat music)

02:22:33.340 | (upbeat music)

Using Caffeine to Optimize Mental & Physical Performance | Huberman Lab Podcast 101

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