How to Optimize Your Brain-Body Function & Health

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

00:00:02.280 | where we discuss science and science-based tools

00:00:04.880 | for everyday life.

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

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

00:00:12.900 | at Stanford School of Medicine.

00:00:15.040 | Today, we continue in our discussion about sensation

00:00:18.480 | or how we sense things.

00:00:20.340 | On previous episodes, we talked about sensing light

00:00:22.880 | and sound waves for things like vision and hearing.

00:00:26.040 | Today, we are going to talk about our sense of self

00:00:29.120 | or what's called interoception.

00:00:31.440 | Interoception is our sensing of our internal landscape,

00:00:35.320 | things like our heartbeat, our breathing, and our gut,

00:00:39.640 | how full our gut might happen to be

00:00:41.960 | or how empty our gut might happen to be,

00:00:44.160 | but also our inner landscape with respect to chemistry,

00:00:47.600 | how acidic or how good or bad we feel on the inside.

00:00:52.600 | This discussion about sense of self and interoception

00:00:55.440 | has many important actionable items

00:00:57.840 | that relate to bodily health and brain health,

00:01:00.920 | and believe it or not, our ability to perform well

00:01:04.040 | or perform poorly in life.

00:01:07.500 | Indeed, it has profound influence on our rates of healing.

00:01:11.760 | So today, we are going to talk about all the aspects

00:01:14.640 | of our inner landscape and how our brain and body

00:01:17.280 | communicate, and there will be many actionable protocols

00:01:20.320 | as we go along that discussion.

00:01:22.200 | Before we begin our discussion about sense of self,

00:01:24.760 | I want to highlight some very recently published

00:01:26.880 | research findings that I believe are immediately actionable

00:01:31.800 | and that everybody should be aware of.

00:01:33.960 | These are data that were published by my colleague,

00:01:35.840 | Justin Sonnenberg's laboratory

00:01:37.460 | at Stanford University School of Medicine,

00:01:39.480 | and the data were published in the journal Cell,

00:01:41.900 | which is a very, very high stringency cell press journal,

00:01:45.640 | so phenomenal data.

00:01:47.680 | What the study showed was that individuals

00:01:50.680 | given a high fiber diet actually experience less diversity

00:01:55.560 | of what's called the gut microbiome.

00:01:57.840 | The number of positive or health-promoting bacteria

00:02:00.640 | in the gut was actually reduced by a high fiber diet,

00:02:04.060 | whereas individuals that ate just a couple of servings

00:02:07.360 | of fermented food each day experienced important

00:02:11.560 | and beneficial increases in anti-inflammatory markers,

00:02:15.240 | and that could be traced back to improvements

00:02:17.800 | in the gut microbiome diversity,

00:02:20.500 | the diversity of bugs, literally little bacteria

00:02:23.520 | that live in the gut, which might sound bad,

00:02:25.400 | but they are actually very health-promoting.

00:02:28.240 | I'm going to get into all the details of this study

00:02:31.160 | later in the episode,

00:02:32.520 | but I just wanted to emphasize these findings

00:02:34.640 | because they are immediately actionable.

00:02:36.640 | I think for most people, ingesting one or two servings

00:02:38.840 | of fermented food each day is reasonable

00:02:41.620 | and does not bring with it tremendous costs

00:02:44.440 | or tremendous inconvenience,

00:02:46.440 | and I think many people are ingesting high fiber diets,

00:02:49.300 | thinking that that's the best way

00:02:50.880 | to improve their gut microbiome.

00:02:52.960 | So while these data may prove to be controversial

00:02:55.200 | among the folks out there in the nutrition community

00:02:58.640 | that really promote high fiber diet,

00:03:00.760 | I want to just emphasize that these data

00:03:02.800 | were looked at in a very unbiased way.

00:03:04.720 | They were done with large-scale screens

00:03:07.000 | of all sorts of inflammatory markers.

00:03:09.120 | There was no specific hypothesis going in.

00:03:11.240 | It was purely exploratory,

00:03:12.840 | but the data are very, very clear.

00:03:15.280 | It doesn't mean you shouldn't eat fiber.

00:03:16.800 | It doesn't mean that fiber is bad,

00:03:18.400 | but it really shows that eating fermented foods,

00:03:20.520 | just one or two servings a day,

00:03:22.200 | and maybe even ramping up to three or four servings per day

00:03:24.960 | can be very beneficial for many aspects of health.

00:03:27.960 | Before we go any further,

00:03:29.200 | I'd like to emphasize that this podcast

00:03:30.840 | is separate from my teaching and research roles at Stanford.

00:03:33.560 | It is, however, part of my desire and effort

00:03:36.000 | to bring zero cost to consumer information about science

00:03:39.000 | and science-related tools to the general public.

00:03:41.780 | In keeping with that theme,

00:03:42.860 | I'd like to thank the sponsors of today's podcast.

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00:08:21.880 | If you're somebody who cares about your immediate

00:08:23.740 | and long-term health,

00:08:25.120 | and if you're somebody who's interested in performance

00:08:27.360 | of any kind in work, in relationships, et cetera,

00:08:31.120 | today's topic, I believe,

00:08:32.420 | is among the more important ones for you.

00:08:35.280 | Of all the topics I could cover,

00:08:37.300 | this thing that we call sense of self,

00:08:39.380 | which is also called interoception,

00:08:41.660 | has perhaps the most foundational level of importance

00:08:45.240 | for all that we feel, all that we do,

00:08:48.420 | and all that we are capable of doing.

00:08:50.420 | In fact, I will go so far as to say that interoception,

00:08:54.080 | or our ability to sense our inner real estate,

00:08:57.500 | is right there next to sleep,

00:08:59.460 | and perhaps one other feature of our health

00:09:02.180 | and bodily function that primarily determine

00:09:06.060 | how good we feel in the now, in the short term,

00:09:09.340 | and in the long term,

00:09:10.860 | and sets the stage for everything we are capable of doing,

00:09:14.660 | and if we don't take care of this thing

00:09:16.400 | that we call interoception,

00:09:18.420 | just like if we don't take care of sleep,

00:09:20.540 | we cannot perform well and we will not remain healthy.

00:09:23.940 | Interoception and sense of self

00:09:26.820 | are essentially the same thing.

00:09:28.580 | I will use those terms interchangeably,

00:09:30.680 | at least for sake of today's discussion.

00:09:32.740 | And I promise that if you can learn a little bit

00:09:35.900 | about the mechanisms of self-sensing,

00:09:38.940 | of understanding what's going on in your internal milieu,

00:09:42.060 | as we say, your internal environment,

00:09:44.540 | you will position yourself to do some very simple things

00:09:48.020 | that can lead to outsize positive effects on everything,

00:09:51.020 | from sleep, to body composition, to mental focus, to mood,

00:09:56.020 | your ability to regulate stress,

00:09:58.660 | and indeed even your ability to heal and recovery

00:10:01.120 | from injuries of different kinds,

00:10:02.500 | brain injury and bodily injury.

00:10:04.360 | So sense of self is absolutely crucial.

00:10:07.420 | It's sometimes called our sixth sense,

00:10:10.020 | right alongside the other five senses,

00:10:12.180 | like hearing, vision, touch, taste, smell, et cetera.

00:10:15.980 | But sense of self is different.

00:10:18.300 | Sense of self is really about what's going on internally

00:10:22.100 | within the confines of our skin.

00:10:24.400 | And it involves two key features

00:10:26.920 | that if you can understand those features

00:10:28.780 | and you understand what modulates

00:10:30.660 | or changes our ability to sense those features,

00:10:33.900 | there are a lot of things that you can do

00:10:36.580 | in terms of how you structure your nutritional practices,

00:10:39.860 | how you relate to your exercise practices,

00:10:42.900 | perhaps even certain things that you take

00:10:44.880 | in terms of supplementation

00:10:46.220 | that can basically make you feel better,

00:10:48.780 | more alert, and more capable for everything.

00:10:52.000 | I don't think that's a hyperbolic statement.

00:10:54.300 | In fact, I know it's not a hyperbolic statement

00:10:56.200 | because we have a system in our body

00:10:59.000 | that connects our brain to all of our bodily organs

00:11:02.480 | and connects all of those bodily organs to our brain.

00:11:06.140 | And that communication between brain and body

00:11:08.700 | in both directions creates a situation

00:11:12.500 | where either we are positioned to do things well

00:11:15.420 | or we are positioned to do things poorly.

00:11:17.820 | So I really want to dive in and dissect

00:11:19.980 | what is this system of brain-body communication?

00:11:22.260 | What does it look like?

00:11:23.100 | What are the actual neurons and connections?

00:11:25.020 | And as I do that,

00:11:26.660 | I promise that I'm going to place protocols,

00:11:28.860 | tools that you can apply in order to make sure

00:11:31.220 | that those neurons and connections are working optimally.

00:11:34.720 | So let's begin by talking about what system

00:11:38.780 | communicates the brain to the body

00:11:40.580 | and the body back to the brain.

00:11:42.340 | The system that's most often associated with this

00:11:45.680 | is our 10th cranial nerve called the vagus nerve.

00:11:49.500 | The word vagus relates to the word vagabond,

00:11:52.700 | which is to wander.

00:11:53.740 | And indeed, the vagus nerve is a vast,

00:11:57.480 | enormous wandering set of nerves.

00:11:59.780 | So it's not one nerve.

00:12:00.760 | It's not like one fiber, one axon, as we say.

00:12:03.500 | In the nervous system, we have these wires we call axons

00:12:06.060 | that let neurons communicate.

00:12:07.500 | It's a bunch of neurons and a bunch of wires

00:12:09.760 | that go everywhere.

00:12:10.600 | So where do they go?

00:12:11.520 | Well, they leave the brain and the brain stem.

00:12:15.600 | The brain stem is kind of the back of your brain.

00:12:17.380 | If you touch the back of your neck,

00:12:18.500 | it's about three inches deep to where you're touching.

00:12:22.020 | The neurons that are there send information into the body

00:12:26.180 | to control your bodily organs.

00:12:28.860 | How fast your heart is beating, how fast you're breathing,

00:12:31.660 | how fast your digestion is occurring.

00:12:34.020 | Even things like whether or not you are going to secrete

00:12:36.780 | so-called killer cells, your immune cells from your spleen

00:12:40.340 | to go ward off bacteria.

00:12:42.920 | Now, the neurons there don't know what to do

00:12:45.580 | unless they receive information about what's going on

00:12:47.980 | within the body.

00:12:49.140 | And within the body, your heart, your lungs, your diaphragm,

00:12:52.180 | your gut, so everything from your intestines

00:12:54.540 | to your stomach, et cetera, and your spleen

00:12:56.900 | are sending information also up to the brain.

00:12:59.680 | So as I mentioned before, it's a two-way street.

00:13:02.480 | So the vagus nerve is a very important nerve,

00:13:05.240 | but just by saying vagus nerve, it sounds like a singular,

00:13:08.260 | it sounds like one thing.

00:13:09.600 | But actually what we're talking about

00:13:11.180 | is a series of super highways.

00:13:12.780 | It's like Google Maps.

00:13:13.740 | It's got stuff going everywhere with alternate routes,

00:13:16.400 | communicating back and forth.

00:13:17.920 | There are two fundamental features

00:13:21.680 | of what's going on in your body

00:13:23.920 | that need to be communicated to your brain,

00:13:26.220 | these neurons in your brain stem,

00:13:27.960 | in order for your brain and your body

00:13:29.540 | to work together correctly.

00:13:31.620 | And the two types of information are mechanical information,

00:13:35.360 | so things like pressure, things like lack of pressure,

00:13:39.960 | and chemical information, whether or not your gut is acidic

00:13:44.280 | or whether or not it's not acidic,

00:13:46.580 | whether or not you have some sort of pathogen,

00:13:49.420 | something that you ate or that got into your body somehow

00:13:52.300 | and is making you sick,

00:13:54.100 | or whether or not you don't have a pathogen in your body.

00:13:57.080 | So you've got mechanical sensing and chemical sensing.

00:13:59.980 | So when you think about your sense of self

00:14:02.020 | and your ability to understand what's going on in your body,

00:14:04.680 | if you feel good or if you feel bad,

00:14:06.980 | your sense of self is dependent

00:14:08.480 | on these mechanical phenomenon and these chemical phenomenon.

00:14:12.980 | And for every organ in your body,

00:14:15.900 | whether or not that's your heart or your lungs

00:14:18.060 | or your spleen,

00:14:19.580 | both the mechanical information about that organ,

00:14:23.420 | for instance, is if your gut is full or empty,

00:14:28.140 | whether or not your heart is beating fast or beating slowly,

00:14:30.820 | that's mechanical.

00:14:32.400 | And chemical information, whether or not your gut feels nice

00:14:35.280 | and whether, you know, when I say nice,

00:14:37.000 | I mean whether or not it has a balance of acidity

00:14:39.540 | and alkalinity that feels right to you,

00:14:41.920 | or whether or not your gut feels off,

00:14:43.700 | it doesn't feel quite right, that's chemical information.

00:14:47.720 | If you are not getting enough oxygen

00:14:50.320 | and levels of carbon dioxide and other gas go up too high,

00:14:53.500 | so your lungs can register that

00:14:56.040 | and that chemical information is sent to your brain

00:14:59.000 | and then your brain does certain things,

00:15:00.740 | actually it really encourages you to do certain things

00:15:03.600 | in order to adjust that chemistry.

00:15:05.660 | So the first principle that everyone should understand

00:15:08.960 | about their sense of self

00:15:10.800 | is that they are sensing mechanical and chemical information

00:15:14.040 | about every organ in their body, except for one,

00:15:18.060 | and that's the brain.

00:15:19.500 | Your brain actually doesn't have pain receptors,

00:15:22.200 | it doesn't even have touch receptors.

00:15:24.000 | The brain is a command center,

00:15:25.800 | it helps drive and govern changes in the organs of the body,

00:15:29.140 | but your brain doesn't move, at least not much,

00:15:30.920 | it can move a little bit, fluid moves within it,

00:15:33.480 | but as long as you're healthy, it's not moving that much.

00:15:36.440 | Your brain has no sensation of its own.

00:15:39.340 | In fact, when they do brain surgery on people,

00:15:41.920 | they will anesthetize or put some anesthesia on the scalp,

00:15:45.040 | they'll cut away the skin there

00:15:46.020 | so that people don't feel anything,

00:15:47.640 | they'll use some anesthesia, they'll peel back the skin,

00:15:50.200 | and then they'll use a, well, let's call it what it is,

00:15:53.640 | it's a bone saw,

00:15:54.620 | and they basically saw open a little window in the skull,

00:15:57.960 | I've actually done this before and seen this before,

00:16:00.000 | I've done this many times before,

00:16:01.820 | and once you're inside the brain,

00:16:03.940 | you can put electrodes in there

00:16:05.760 | and you can put various things in there,

00:16:07.640 | of course, all for therapeutic purposes,

00:16:09.800 | and you do that without any anesthesia

00:16:12.060 | to the actual brain tissue

00:16:13.220 | because it has no receptors to sense anything.

00:16:17.120 | It doesn't have pain receptors,

00:16:18.920 | it doesn't have pressure receptors, none of that.

00:16:21.160 | When you have a headache

00:16:22.040 | and your head feels like there's too much pressure,

00:16:24.520 | well, that's because of receptors that lie outside the brain.

00:16:27.720 | So your organs are different,

00:16:29.800 | they need to tell your brain what's going on,

00:16:32.040 | and there are ways that you can control the mechanical

00:16:35.900 | and the chemical state of your organs

00:16:38.480 | in ways that are very powerful,

00:16:40.700 | and this is crucial to do

00:16:42.120 | because if you can properly regulate

00:16:45.080 | the mechanical and chemical environment of your body,

00:16:48.280 | your brain functions better.

00:16:49.960 | This is absolutely clear from data

00:16:52.940 | that if your gut is healthy,

00:16:54.320 | if you get the alkalinity right, the acidity right,

00:16:57.720 | and if your spleen is healthy and happy,

00:16:59.680 | and if your lungs are working properly,

00:17:01.800 | not just breathing and pumping in and out air,

00:17:04.180 | but you're breathing at the right cadence

00:17:05.640 | for a particular activity,

00:17:07.220 | then your brain will function better.

00:17:09.700 | So let's talk about how you can adjust

00:17:12.120 | the mechanical and chemical environment of your organs

00:17:15.280 | in order to make your brain better,

00:17:16.920 | and how your brain can make the mechanical

00:17:19.360 | and chemical environment within your organs function better.

00:17:23.500 | For instance, we're going to talk about

00:17:25.220 | how you can change the chemistry of your gut

00:17:27.880 | in order for your brain to be able to focus better,

00:17:30.600 | think better, remember better, and sleep better,

00:17:33.240 | and we're going to talk about how you can change

00:17:35.380 | the chemistry of other organs in your body

00:17:37.880 | such that your immune system will function better

00:17:40.040 | than it would otherwise,

00:17:41.100 | and you can actually heal faster from small cuts and bruises,

00:17:44.460 | but also injuries of any kind, even major injuries.

00:17:47.900 | So as I mentioned before, we've got these organs,

00:17:51.860 | the heart, the lungs, the diaphragm,

00:17:54.100 | and I'll explain what that is, the gut and the spleen,

00:17:57.760 | and the spleen is this immune organ.

00:17:59.500 | Let's take one example of these

00:18:02.500 | and explain how mechanical and chemical information

00:18:05.940 | from this particular set of organs

00:18:08.740 | communicates to the brain and how that changes

00:18:11.100 | how our brain works.

00:18:12.420 | And the organ I'd like to focus on first

00:18:15.060 | are the lungs and the diaphragm.

00:18:17.520 | So we're all familiar with our lungs,

00:18:18.780 | these two big bags of air,

00:18:20.120 | but they're actually not two big bags of air,

00:18:21.480 | they actually have little tiny sacs within them,

00:18:23.840 | actually millions of little sacs

00:18:25.600 | called the avioli of the lungs.

00:18:27.680 | The avioli of the lungs are like little tiny balloons

00:18:30.160 | throughout our lungs, and the more of those balloons we have,

00:18:32.520 | the more air that we can actually contain.

00:18:34.300 | So we are not two big bags of air in there, our lungs,

00:18:37.660 | we actually have millions and millions

00:18:39.660 | of little tiny bags of air within those lungs.

00:18:42.020 | Those little bags of air can fill up or they can deflate,

00:18:47.620 | just like your lungs overall can fill up

00:18:49.660 | or they can deflate.

00:18:51.180 | The diaphragm is a muscle, it's kind of shaped like a dome,

00:18:54.620 | so it's kind of, think about a basketball or a soccer ball

00:18:58.820 | that has most of the air pushed out of it,

00:19:01.300 | and so it's kind of crescent shape or dome shaped,

00:19:04.060 | and it sits below our lungs.

00:19:06.100 | And the way the diaphragm and the lungs work together

00:19:08.420 | is very interesting.

00:19:09.420 | The diaphragm is actually skeletal muscle,

00:19:11.300 | so it's just like a bicep or a quadricep,

00:19:13.540 | and the fact that it is skeletal muscle is important

00:19:16.120 | because it has a unique property,

00:19:18.600 | which is that you can control it voluntarily,

00:19:21.080 | you can decide to take control of your diaphragm

00:19:24.140 | by just consciously deciding you want to breathe

00:19:26.140 | in a particular way.

00:19:27.380 | Just like you can take conscious control over your legs,

00:19:30.020 | they will work just fine if you're not thinking about them

00:19:32.060 | as you walk, provided you already know how to walk,

00:19:34.420 | but at any moment you can decide to change the rate

00:19:36.760 | of your walking, your so-called cadence of walking.

00:19:40.040 | So the diaphragm as a skeletal muscle

00:19:42.240 | also has that property.

00:19:43.660 | The diaphragm moves up and down depending on how you breathe,

00:19:46.740 | or rather I should say how the diaphragm moves up and down

00:19:50.580 | determines how you breathe.

00:19:51.900 | How you breathe is also dependent on little muscles

00:19:53.980 | that are between your ribs,

00:19:55.340 | the intercostals and other muscles.

00:19:58.120 | If you're a martial arts fan, Bruce Lee was famous

00:20:00.500 | for having these very pronounced intercostals

00:20:03.860 | from doing all sorts of bridging exercise, et cetera,

00:20:06.820 | but those are the muscles and we all have them

00:20:09.140 | even if some of us, most of us don't have intercostals

00:20:13.280 | like Bruce Lee.

00:20:14.740 | So when you breathe, a couple of things happen,

00:20:17.540 | but let's talk about the mechanical things first

00:20:20.000 | and then let's talk about how those mechanical steps

00:20:22.860 | relate back to the brain and what that does for the brain.

00:20:26.520 | And I can promise you that if you develop an awareness

00:20:29.460 | of these mechanical changes,

00:20:31.260 | you do not have to go through extensive breath work practice

00:20:35.060 | or do extensive breath work.

00:20:37.000 | You will immediately, believe it or not,

00:20:39.220 | develop a sense of your breathing self,

00:20:42.960 | of your lungs and diaphragm.

00:20:44.480 | It takes no practice, but once you do it,

00:20:46.760 | you will forever be changed in terms of your awareness

00:20:49.140 | of your breathing and your ability to leverage

00:20:51.300 | your breathing, kind of like the steering wheel on a car

00:20:53.580 | in order to shift your brain in the direction

00:20:55.960 | that you want to go.

00:20:56.800 | So it's a very powerful system.

00:20:58.340 | And the way it works is the following,

00:21:00.280 | and this will also incorporate the heart.

00:21:03.260 | So, and by the heart, I don't mean it in the emotional sense.

00:21:06.220 | Although we don't rule out emotions here

00:21:08.460 | at the Huberman Lab Podcast, we like emotions,

00:21:10.720 | but I'm talking about the heart as an organ,

00:21:14.420 | as a beating organ that circulates blood.

00:21:17.360 | So when we inhale, these little sacs in our lungs fill up

00:21:22.360 | and our lungs expand.

00:21:24.440 | And when we do that, we take up space in our thoracic cavity

00:21:28.360 | and our diaphragm moves down, okay?

00:21:32.840 | When we exhale, the diaphragm moves up,

00:21:35.680 | the lungs get smaller, okay?

00:21:37.440 | So inhales, diaphragm moves down, exhales,

00:21:40.620 | diaphragm moves up.

00:21:41.920 | This actually controls our heart rate,

00:21:45.440 | but it does it by changing the way that our brain works.

00:21:49.000 | And it works in the following way.

00:21:50.720 | So when we inhale, our lungs fill, our diaphragm moves down,

00:21:55.080 | our heart actually has a little more space

00:21:57.120 | because the diaphragm's moved down.

00:21:58.960 | So the heart gets a little bit bigger, physically bigger,

00:22:01.680 | not in the emotional sense, but physically bigger.

00:22:04.640 | And as a consequence, whatever blood is in the heart

00:22:07.880 | flows at a slower rate because it's a larger volume.

00:22:11.760 | So bigger volume heart,

00:22:13.520 | same amount of blood inside the heart means slower flow,

00:22:17.320 | okay, sort of like expanding a pipe.

00:22:19.300 | The brain registers that

00:22:20.860 | because there are a set of neurons on the heart

00:22:22.400 | called the sinoatrial node.

00:22:24.560 | It sends that information to the brain.

00:22:27.600 | That information is registered by the brain

00:22:29.900 | and the brain sends a message back to the heart

00:22:32.320 | to speed the heart up.

00:22:34.680 | So every time you inhale,

00:22:36.480 | because of these mechanical changes in the diaphragm and lungs

00:22:40.360 | and because of the mechanical changes in the heart,

00:22:43.360 | your brain sends a signal to the heart to speed the heart up.

00:22:47.160 | So if you do long inhales or you inhale more vigorously,

00:22:51.600 | you actually are speeding your heart up.

00:22:54.480 | Now, of course, you have to exhale as well.

00:22:56.880 | But for instance, if I were to inhale very long,

00:22:58.940 | like the entire time, my heart rate is increasing.

00:23:02.760 | And then if I did a quick exhale, something else will happen.

00:23:06.720 | But if I kept doing that, my heart rate would increase.

00:23:11.720 | It's not going to increase linearly and forever,

00:23:14.120 | but it will increase with each inhale.

00:23:17.000 | Or I can simply make my inhales more vigorous

00:23:20.040 | and my heart rate will speed up.

00:23:21.520 | This is an autonomic and automatic relationship

00:23:25.340 | between the diaphragm, the lungs, the brain, and the heart.

00:23:29.140 | Now, if inhales speed the heart up, what happens on exhales?

00:23:31.960 | When we exhale, the diaphragm moves up.

00:23:36.080 | It's a little counterintuitive,

00:23:37.160 | but you can kind of think about it

00:23:39.140 | as like pushing the plunge on a syringe, right?

00:23:41.200 | When you exhale, this thing moves up.

00:23:44.520 | And as the diaphragm moves up, the heart has less space,

00:23:49.280 | meaning it gets a little bit smaller,

00:23:51.360 | which means that whatever volume of blood is inside the heart

00:23:53.920 | moves faster through that smaller volume.

00:23:57.140 | That information is sent to the brain

00:23:59.480 | via these collection of neurons

00:24:01.040 | called the sinoatrial node, for you aficionados.

00:24:04.400 | The brain then sends information via the vagus nerve

00:24:08.440 | back to the heart to slow the heart down.

00:24:11.980 | So while inhales speed up the heart, that's the net effect,

00:24:16.200 | exhales slow the heart down.

00:24:18.320 | And the reason they slow the heart down

00:24:19.840 | is because of a register in the change in mechanical pressure

00:24:24.080 | between the diaphragm, the lungs, and the heart.

00:24:26.760 | So this is, to me,

00:24:28.280 | the simplest and most straightforward example

00:24:30.880 | of how the brain is changing the way our organs work,

00:24:34.320 | our heart in this case,

00:24:35.960 | according to changes in mechanical interoception.

00:24:39.860 | Now, we're not always aware of this.

00:24:41.680 | Some of us are aware of it, some of us aren't.

00:24:44.220 | If you do it right now, you will be aware of it.

00:24:46.120 | So you can try this.

00:24:48.000 | Basically, this is an experiment or an example

00:24:50.280 | in interoception, in sensing one's self.

00:24:53.600 | So if you inhale, doesn't matter how long you inhale,

00:24:56.160 | I'll do it for a couple seconds,

00:24:58.160 | and then exhale twice as long.

00:25:00.200 | Nose or mouth, doesn't matter.

00:25:04.260 | The entire time that you're exhaling,

00:25:05.840 | you're slowing your heart down.

00:25:08.040 | So just as a car has an accelerator and a brake,

00:25:10.760 | or you can slow a car by coming off the accelerator,

00:25:13.720 | when you exhale,

00:25:14.560 | you're effectively coming off the accelerator,

00:25:16.480 | or if you want to think about it differently,

00:25:18.400 | you're hitting the brake,

00:25:19.580 | you're slowing down your heart rate.

00:25:21.680 | Now, normally your heart rate stays in more or less

00:25:23.520 | the same range for a given activity

00:25:26.220 | because you're inhaling and exhaling.

00:25:28.440 | But this is just a simple way of showing

00:25:30.440 | that mechanical changes in your viscera

00:25:33.320 | can change the way that your brain works,

00:25:35.120 | and then your brain changes the way that those viscera work.

00:25:37.880 | And it's a very concrete agreements,

00:25:40.440 | like a contract between the organs of your body

00:25:42.880 | and the brain.

00:25:44.360 | In fact, you can think about this contract

00:25:46.360 | in more detail,

00:25:47.280 | and you can leverage this in a very powerful way

00:25:49.440 | to set the conditions of your mind.

00:25:51.380 | If you want to be more calm, emphasize exhales.

00:25:56.260 | And the simplest way to do this,

00:25:57.400 | I've talked about this many times before,

00:25:59.400 | but if you haven't heard me say it,

00:26:00.640 | this will become immediately clear,

00:26:02.240 | is to emphasize exhales

00:26:03.880 | through what's called a physiological sigh.

00:26:06.980 | Two inhales could be through the nose or the mouth,

00:26:09.560 | but ideally through the nose.

00:26:10.680 | So followed by a long exhale.

00:26:15.600 | Those double inhales are kind of important

00:26:17.440 | because what they do is they maximally fill

00:26:19.200 | all those little sacks in your lungs.

00:26:20.680 | And then when you breathe out,

00:26:22.540 | you're exhaling as much of the so-called carbon dioxide

00:26:26.000 | in your system as possible.

00:26:27.160 | We'll talk about carbon dioxide in a second.

00:26:29.120 | So the fastest way to calm down is to emphasize exhales.

00:26:33.800 | When you make exhales longer,

00:26:35.460 | you're slowing your heart rate, you're calming down.

00:26:38.200 | You don't need any sophisticated training.

00:26:39.860 | You don't have to do this for minutes on end.

00:26:41.800 | You don't have to do anything.

00:26:42.720 | You don't even have to call it breath work.

00:26:43.980 | It's just respiration.

00:26:45.240 | And in fact, you do this every night when you go to sleep

00:26:47.560 | and carbon dioxide builds up too much in your bloodstream,

00:26:50.320 | or if you hold your breath or something,

00:26:52.180 | or you watch an animal or a small child that's sleeping,

00:26:56.400 | they will occasionally do these double inhale long exhales.

00:26:58.960 | It's a way of slowing the heart down

00:27:00.480 | and eliminating carbon dioxide.

00:27:02.580 | The opposite is also true.

00:27:05.520 | If you inhale deeply or vigorously,

00:27:09.040 | and then exhale less long or less vigorously,

00:27:13.160 | you will increase your level of alertness

00:27:15.200 | through these purely mechanical aspects

00:27:18.080 | of your interoception.

00:27:19.880 | So for instance, if I were to take a big, deep inhale,

00:27:22.640 | and then a short exhale, and then another one,

00:27:27.200 | big inhale, short exhale,

00:27:28.700 | it only takes two or three of those

00:27:30.120 | before you start to feel more alert.

00:27:32.520 | And that's because your heart rate is increasing.

00:27:34.360 | And actually, if you keep doing that for 25 or 30 breaths

00:27:37.280 | of inhale deep, short exhale,

00:27:39.440 | you will start to secrete a lot of adrenaline,

00:27:41.960 | this hormone that comes from your kidneys

00:27:43.520 | and from your brainstem make you feel really alert.

00:27:46.620 | You will actually feel as if you've had a couple of espresso,

00:27:49.960 | you will immediately wake up.

00:27:51.520 | And there's an intermediate form of breathing,

00:27:54.880 | which is sometimes called box breathing,

00:27:56.360 | but it's really equal inhale and exhale duration.

00:27:59.520 | And these, it basically goes like this.

00:28:01.480 | You're going to inhale.

00:28:02.400 | So do this for maybe two, three seconds.

00:28:03.960 | Inhale, then hold, two, three seconds,

00:28:08.100 | then exhale, two, three seconds, then hold, two, three seconds.

00:28:13.040 | Most often people forget to hold.

00:28:14.340 | So it's inhale, hold, exhale, hold

00:28:18.040 | for equal or more or less equal duration.

00:28:20.400 | So it could be one second, could be two seconds,

00:28:22.240 | could be three seconds.

00:28:23.320 | Most people find that when you get out past five seconds,

00:28:25.420 | they start to struggle

00:28:26.600 | to maintain the so-called box breathing.

00:28:28.200 | And most people can't consciously box breathe

00:28:31.500 | for too terribly long without having to think about it.

00:28:34.060 | But the point here is that through purely mechanical means,

00:28:38.960 | changing the way that you breathe,

00:28:40.720 | emphasizing inhales or exhales or keeping them the same,

00:28:43.240 | will change the way that your brain works,

00:28:45.040 | how alert you are and how well you function in anything.

00:28:47.800 | And again, this doesn't mean that breath work has no value.

00:28:51.160 | It's just simply to say

00:28:52.240 | that long extended protocols of breath work are simply,

00:28:56.120 | they are truly simply just an exploration

00:28:58.740 | of this fundamental relationship

00:29:00.240 | between the mechanics of your internal organs

00:29:03.240 | and your brain and how your brain controls

00:29:05.420 | those internal organs.

00:29:07.080 | Now, you might ask, well, how is this pressure known?

00:29:11.720 | How does the body actually know how full the lungs are?

00:29:14.340 | Now, this is an answer

00:29:15.780 | that's more for the aficionados out there,

00:29:17.380 | but I've had a few requests or I should say thousands

00:29:19.500 | of requests for more in-depth science.

00:29:21.800 | So if you're not interested in more in-depth science,

00:29:24.260 | just this will allow you to tune out now

00:29:26.760 | for maybe just 10 seconds.

00:29:27.940 | And if you are interested, pay careful attention.

00:29:30.040 | There is a set of receptors which are called piezo receptors,

00:29:35.040 | P-I-E-Z-O, piezo receptors.

00:29:38.320 | Piezo means pressure.

00:29:39.760 | And these were discovered a few years ago

00:29:41.400 | by a couple of different laboratories.

00:29:42.920 | But one of the main ones,

00:29:44.920 | one of the main laboratories

00:29:45.920 | that discovered these piezo receptors

00:29:47.920 | is the laboratory of Ardem Padepuchen.

00:29:50.520 | I love saying his name,

00:29:51.540 | even though I'm probably pronouncing it.

00:29:53.520 | He's a friend and a former colleague.

00:29:55.520 | When my lab was down in San Diego,

00:29:56.960 | he's at the Scripps Institute.

00:29:58.760 | He's a Howard Hughes Medical Institute investigator,

00:30:01.240 | which just basically means that he's a total stud of science

00:30:04.620 | and has made many important discoveries.

00:30:07.480 | The piezo receptors line many tissues

00:30:11.440 | and inform the brain about pressure in those tissues.

00:30:14.240 | But the lungs have a particular category of piezo receptors

00:30:18.160 | called piezo two receptors.

00:30:19.680 | And as you fill your lungs [inhales]

00:30:22.260 | and these little sacks of air, the alveoli fill,

00:30:25.320 | the piezo two receptors,

00:30:28.040 | because of the way they react to that filling,

00:30:31.040 | send information by way of a bunch of neurons,

00:30:33.600 | a bunch of wires up to the brain

00:30:34.900 | and tell you how full your lungs are.

00:30:36.720 | So that's the kind of mechanistic detail.

00:30:38.280 | If you want to learn more about that,

00:30:39.560 | you can look up Ardem's lab at the Scripps

00:30:43.520 | and the beautiful work that they and other laboratories

00:30:45.720 | are doing on piezos.

00:30:47.120 | Piezos are pretty cool.

00:30:48.380 | I think I also just like saying piezo.

00:30:50.200 | So that's why I brought that up as well.

00:30:52.280 | So mechanical sensing of the lungs, heart and diaphragm.

00:30:56.600 | And now let's talk about chemical sensing

00:30:58.280 | because there's carbon dioxide and there's oxygen.

00:31:00.560 | And this is really simple.

00:31:02.340 | You have oxygen and carbon dioxide and you need them both.

00:31:06.240 | I sometimes hear people talk about carbon dioxide

00:31:08.200 | as this bad thing and oxygen as a good thing.

00:31:11.000 | You need them both and you need them

00:31:12.240 | in the appropriate balance.

00:31:13.900 | You have a collection of neurons in your brain

00:31:16.560 | that register when carbon dioxide levels

00:31:19.160 | get to a certain point in your bloodstream.

00:31:23.040 | When that point, that threshold is reached,

00:31:25.840 | these neurons fire and they cause you to breathe.

00:31:28.680 | It's sometimes called the gasp reflex.

00:31:31.060 | It just makes you want to inhale.

00:31:32.300 | And as a consequence, you bring in more oxygen.

00:31:35.800 | Okay, so we don't really breathe to get oxygen.

00:31:38.560 | That's a by-product of inhaling

00:31:41.400 | to eliminate carbon dioxide.

00:31:44.120 | You don't want carbon dioxide levels to go too high.

00:31:47.120 | In fact, if you want to freak somebody out

00:31:49.620 | and we do these in experiments,

00:31:51.060 | and I don't recommend you do this,

00:31:52.400 | you just increase the levels of carbon dioxide

00:31:54.580 | that they inhale and the brain will go

00:31:56.640 | into an almost immediate panic response

00:31:59.800 | because the health of all our tissues depends

00:32:02.000 | on keeping a nice balance between carbon dioxide and oxygen.

00:32:04.800 | You don't want carbon dioxide levels to go too high.

00:32:07.320 | So the impulse to breathe, if you're underwater

00:32:10.360 | or if you hold your breath, is triggered by these neurons.

00:32:13.720 | And the triggering of those neurons

00:32:16.000 | comes from elevated carbon dioxide in the bloodstream.

00:32:18.840 | And for those of you that don't quite know

00:32:21.400 | how to conceptualize the relationship

00:32:23.000 | between bloodstream and breath, I do think it's important,

00:32:26.260 | and maybe you remember this from high school biology,

00:32:27.940 | but if you don't, I'll make it clear for you now.

00:32:30.260 | It's very easy.

00:32:31.260 | You inhale air and that air and the oxygen molecules

00:32:36.260 | in that air actually move from your lungs

00:32:39.000 | into the bloodstream because these little avioli

00:32:41.140 | of the lungs, those little sacks of air,

00:32:43.600 | they basically have a lot of little micro vessels

00:32:48.600 | and capillaries, little tiny, basically blood vessels,

00:32:52.460 | essentially, although they're mostly capillaries,

00:32:54.120 | micro capillaries, little tiny ones that line them.

00:32:57.120 | So there's actually an interface, an opportunity for air

00:33:01.320 | and molecules within the air to pass into the blood.

00:33:04.260 | And then they move in your bloodstream.

00:33:05.740 | And when you exhale, the opposite is true.

00:33:08.660 | So you can move things from the air into your bloodstream

00:33:11.880 | or from your bloodstream into the air by way of the lungs.

00:33:15.100 | And there's a lot more detail to it.

00:33:16.620 | And I'm sure those of you that are experts out there,

00:33:18.940 | if you want to put some stuff in the comments,

00:33:20.500 | maybe a little bit of an kind of intermediate tutorial,

00:33:22.980 | you might even title it intermediate tutorial.

00:33:25.680 | If you know a lot about this, just I'll check it,

00:33:27.920 | but make sure you get the details right.

00:33:29.180 | Make sure you know the process.

00:33:31.160 | And I find that for people that are interested

00:33:33.900 | in understanding how breathing really works,

00:33:35.840 | it's really nice to think about the relationship

00:33:37.600 | between the heart and the vascular system,

00:33:40.360 | the blood and the air system,

00:33:43.280 | the respiration system and breathing,

00:33:45.160 | because those two things are very,

00:33:47.720 | we say they're interdigitated,

00:33:49.200 | they're interwoven with one another.

00:33:51.300 | So how's this work?

00:33:52.940 | Well, carbon dioxide is too high.

00:33:55.140 | You breathe in, you inspire, you inhale.

00:33:57.780 | As a consequence, when you exhale,

00:34:00.060 | you offload carbon dioxide.

00:34:02.000 | There's a really cool way that you can explore

00:34:04.100 | this chemistry of your breathing and your bloodstream

00:34:06.400 | and the way that your brain works

00:34:07.500 | in ways that can really benefit your health.

00:34:09.900 | And it works the following way.

00:34:12.260 | You want to essentially sit or lie down.

00:34:15.240 | It doesn't really matter.

00:34:17.140 | You definitely don't want to be anywhere near water,

00:34:19.940 | not a bathtub, not a hot tub,

00:34:21.540 | not a cold dunk or something.

00:34:24.220 | In fact, don't even be in a puddle.

00:34:26.680 | And what you want to do in this case

00:34:28.580 | is you're going to breathe in deep,

00:34:29.980 | so that's going to increase your heart rate,

00:34:31.420 | and then exhale passively

00:34:33.340 | by just letting air fall out of your mouth.

00:34:35.080 | So it would look something like this.

00:34:36.580 | [inhales and exhales]

00:34:38.060 | So let's say you breathe in vigorously

00:34:39.680 | and then you let the air just fall out of your mouth.

00:34:43.780 | When you do that, what you're essentially doing

00:34:46.100 | is you're bringing in a lot of oxygen

00:34:47.740 | through that deep breath,

00:34:49.260 | and you're exhaling a little bit of that carbon dioxide.

00:34:53.580 | But if you were to repeat it 25 times, maybe 30 times,

00:34:57.300 | doesn't matter if it's 25 or 30, somewhere in there,

00:35:00.820 | you would essentially start bringing in a lot of oxygen

00:35:03.700 | and blowing off or exhaling a lot of carbon dioxide.

00:35:07.300 | So you're actually going to change the chemistry

00:35:09.860 | of your internal landscape, and you can then sense it.

00:35:13.060 | You can interocept what that is like.

00:35:15.820 | And there are some really interesting reasons

00:35:18.000 | for wanting to do that.

00:35:19.060 | So I'm not going to do all 25 or 30 now,

00:35:20.800 | maybe do five or 10 so you can get a sense

00:35:22.840 | of what it looks like so that it's clear.

00:35:25.240 | I'm going to essentially demonstrate now.

00:35:27.420 | So it's inhale, exhale through the mouth.

00:35:30.060 | I am inhaling through the nose.

00:35:31.480 | [inhales and exhales]

00:35:34.560 | So it's essentially, excuse me,

00:35:41.300 | a two-second or so inhale,

00:35:43.620 | and then a one-second or so exhale.

00:35:45.220 | And as I was doing that,

00:35:46.060 | I can kind of feel my face get flush

00:35:47.880 | and my body is heating up and my brain is heating up.

00:35:50.100 | What's happening there?

00:35:50.940 | Well, that pattern of breathing is increasing levels

00:35:54.380 | of adrenaline in my brain and body,

00:35:56.060 | and I'm getting more alert.

00:35:58.040 | Then after 25 or 30 of those, you exhale all your air.

00:36:03.660 | [exhales]

00:36:05.020 | You dump all your air.

00:36:06.780 | You can do that your nose or your mouth.

00:36:08.940 | And then you hold your breath with your lungs empty

00:36:11.160 | for about 15 to 30 seconds.

00:36:13.720 | Now, for those of you that want to explore this,

00:36:15.800 | and please be careful as you explore this,

00:36:17.880 | don't do anything stupid like do this while you're driving

00:36:20.120 | or something like that.

00:36:22.240 | You can exhale all your air.

00:36:24.200 | And what you'll find then is you can hold your breath

00:36:26.300 | for a very long time.

00:36:28.820 | And the reason you can do that is because you've blown off

00:36:32.660 | all the carbon dioxide or most of the carbon dioxide

00:36:35.700 | in your bloodstream.

00:36:36.540 | So you've shifted the chemistry of your blood

00:36:39.840 | by breathing in a particular way.

00:36:42.320 | And by doing that, you are no longer triggering these neurons

00:36:45.880 | that cause the gasp reflex or the reflex to breathe.

00:36:49.580 | Now, of course, you have to breathe sooner or later,

00:36:51.160 | but what you'll find is if normally your ability

00:36:53.920 | to hold your breath is a minute or so

00:36:56.200 | before you really feel that gasp reflex kick in,

00:36:59.260 | you might find that you can go 90 seconds or two minutes.

00:37:02.300 | And with some practice, people find that they can start

00:37:04.180 | holding their breath for three or four minutes or longer.

00:37:06.140 | This is actually how free divers do what they do.

00:37:07.860 | I do not want anyone free diving.

00:37:10.200 | If you're going to learn free diving,

00:37:11.580 | please learn it from an expert.

00:37:13.620 | Many people die trying to teach themselves out of free dive

00:37:16.180 | or trying to teach their friends out of free dive

00:37:17.720 | when they don't know what they're doing.

00:37:19.280 | This is not what this is about.

00:37:20.920 | Again, don't do this anywhere near water,

00:37:22.680 | but it is a very interesting exploration

00:37:25.500 | of how you can shift the chemistry of your bloodstream

00:37:28.340 | by modulating your air, by modulating the mechanics

00:37:31.800 | of your diaphragm and lungs,

00:37:33.080 | and thereby shift the way your mind works, your brain.

00:37:37.160 | In fact, what you'll notice is that even though

00:37:39.440 | during that 25 or 30 breaths, [inhales and exhales]

00:37:43.400 | you'll feel very alert.

00:37:44.680 | When you exhale all your air and you're in the breath hold,

00:37:48.980 | you will feel very alert, but very, very calm.

00:37:52.640 | Now, this is interesting because it's a state

00:37:55.980 | that we all sort of want to achieve, alert but calm,

00:37:58.600 | but have a hard time achieving.

00:38:00.220 | And so for those of you that have a hard time

00:38:02.480 | obtaining focus for sake of work

00:38:04.940 | or focus for sake of anything, I should say,

00:38:07.680 | and when you are able to achieve focus,

00:38:10.200 | it's through the use of things like stimulants,

00:38:12.120 | or you feel like you have to have a cold shower or ice bath,

00:38:14.560 | or you have to have four espresso in order to be alert,

00:38:17.720 | but then you're too alert, you're jittery, you can't focus.

00:38:20.920 | This pattern of breathing can lend itself very well

00:38:23.960 | to entering states of alert but calm

00:38:26.920 | for the 10 or even 20 minutes that follow that breathing,

00:38:31.160 | and then you could repeat it if you want.

00:38:32.840 | So it's a very useful practice to explore.

00:38:35.280 | Some of you may be familiar with this practice,

00:38:37.520 | a so-called Wim Hof breathing.

00:38:39.120 | Wim Hof is a practitioner of what's called tumor breathing.

00:38:41.700 | Tumor breathing has been around for centuries.

00:38:43.760 | And for those of you that are familiar with breath work

00:38:46.880 | and yoga practices,

00:38:49.080 | I acknowledge that nothing I just described

00:38:51.240 | is new based on science.

00:38:53.000 | However, the science informs why those practices work.

00:38:56.880 | And just as a little mini editorial,

00:38:59.840 | I just want to emphasize as well

00:39:02.160 | that one thing that this podcast is really about

00:39:05.320 | is trying to remove fancy nomenclature,

00:39:08.160 | whether or not it's yogic nomenclature

00:39:09.900 | or scientific nomenclature

00:39:11.120 | so that people can access protocols.

00:39:12.740 | Because the moment we start naming things after people

00:39:15.920 | or calling them Tumor, et cetera,

00:39:18.080 | I have no problem with that,

00:39:19.240 | but it doesn't inform how the practices are done,

00:39:21.440 | nor does it inform the underlying mechanisms.

00:39:23.560 | So here I'm trying to teach you the mechanisms.

00:39:25.840 | And as a final point to that,

00:39:28.080 | the most powerful form of breathing

00:39:30.260 | is the one that takes into account

00:39:31.820 | the fundamental mechanisms that else increase heart rate

00:39:35.280 | that exhales decrease heart rate,

00:39:37.840 | and that carbon dioxide and oxygen

00:39:40.560 | relate to the bloodstream and the brain in particular ways.

00:39:44.020 | Once you understand those components,

00:39:46.460 | then you can create your own so-called breath work practices.

00:39:49.180 | You can breathe in the ways that best serve you,

00:39:51.920 | as opposed to thinking that one protocol

00:39:54.120 | is the best or holy protocol for everything,

00:39:56.920 | because it's simply not.

00:39:58.120 | As a final, final point,

00:40:00.960 | I want to say that as you shift the way that you breathe,

00:40:05.560 | whether or not you're blowing off more carbon dioxide

00:40:07.920 | or bringing in more oxygen,

00:40:09.200 | you are fundamentally changing the chemistry

00:40:11.920 | of your internal milieu of your body.

00:40:14.120 | And that has been shown to have important effects

00:40:17.160 | on the way that your immune system functions

00:40:19.000 | and the way that you deal with inflammation

00:40:21.720 | and all sorts of different sort of things

00:40:24.660 | that can enter your body and cause problems

00:40:26.640 | or conditions of stress, et cetera.

00:40:29.220 | So I will explore that further as the episode goes on,

00:40:32.140 | but I want to move on to just touch on one other aspect

00:40:35.880 | of breathing that's purely mechanical,

00:40:38.120 | which I think is very interesting and important,

00:40:40.420 | which relates to a particular reflex

00:40:42.940 | that you're going to be very familiar with in a second,

00:40:45.200 | and that can serve you very well in times of extreme stress.

00:40:48.700 | The reflex I'm referring to

00:40:49.980 | is something called the Herring-Brewer reflex.

00:40:52.740 | I'm not going to go into details

00:40:54.040 | about how the Herring-Brewer reflex works,

00:40:55.900 | but it has to do with particular classes of neurons

00:40:59.440 | and cells that are called a baroreceptors.

00:41:02.360 | Those are basically pressure receptors.

00:41:04.780 | They sense pressure.

00:41:06.200 | And basically what the Herring-Brewer reflex is about

00:41:09.160 | is that when your lung is inflated,

00:41:11.320 | your desire to breathe is reduced.

00:41:14.000 | So you can try that right now.

00:41:15.720 | You can inhale, huge big dig of air, and hold, okay?

00:41:22.660 | Your desire to breathe will kick in later

00:41:26.140 | than were you to exhale all your air and hold your breath.

00:41:31.140 | When you exhale all your air and hold your breath,

00:41:34.020 | unless you've done the sort of protocol

00:41:35.760 | I described a few minutes ago

00:41:36.960 | of doing a bunch of inhales and exhales first

00:41:39.000 | in a very deliberate way, you will feel empty.

00:41:42.020 | Those baroreceptors are going to be firing like crazy

00:41:44.720 | saying there's no pressure in here.

00:41:45.860 | There's no pressure in here.

00:41:46.700 | I got nothing in here.

00:41:48.100 | You need to breathe.

00:41:48.940 | You need to breathe,

00:41:49.760 | and the gas reflex will kick in sooner.

00:41:51.940 | You can apply that in all sorts of situations

00:41:54.540 | related to exercise,

00:41:57.340 | related to modulating stress, et cetera.

00:42:00.140 | So the Herring-Brewer reflex is a very powerful one.

00:42:03.220 | This is why you take a big deep breath

00:42:04.940 | before you go underwater, all right?

00:42:07.720 | You're not going to exhale all your air and go underwater.

00:42:10.000 | If you were to exhale all your air and go underwater,

00:42:12.480 | you would absolutely feel the need to come up sooner

00:42:14.740 | for a breath of air than had you a full tank, so to speak,

00:42:19.120 | a full lungs full of air.

00:42:21.580 | And this is also the way that people teach themselves

00:42:24.500 | to feel comfortable underwater.

00:42:26.680 | So when you learn how to swim,

00:42:27.660 | you learn how to swim both by having air in your lungs

00:42:29.800 | while you're underwater

00:42:30.640 | and no air in your lungs while you're underwater.

00:42:33.920 | In any event, the Herring-Brewer reflex

00:42:35.660 | is yet another dimension to the way

00:42:38.180 | that mechanical pressure influences

00:42:40.440 | your brain's decision-making

00:42:42.620 | about what to do with your body,

00:42:44.000 | in this case, whether or not to breathe.

00:42:46.180 | So now I want to shift away from breathing

00:42:48.600 | and diaphragm and lungs

00:42:50.000 | and move toward another organ within our viscera,

00:42:53.460 | which is our gut.

00:42:55.240 | So this includes our stomach and our intestines,

00:42:57.140 | our esophagus and so forth.

00:42:59.540 | It's been said before, both by me and by others,

00:43:01.980 | that we are but a series of tubes.

00:43:04.100 | And indeed, that's true.

00:43:05.080 | Believe it or not, every system in your body is a tube.

00:43:08.840 | Your brain is actually a tube

00:43:11.040 | that connects to your spinal cord, which is also a tube.

00:43:13.620 | You started off as a tube.

00:43:15.060 | You were like a churro.

00:43:16.080 | You know those like churros?

00:43:17.200 | I don't know if you're not familiar with churros.

00:43:18.400 | They're like donuts that are shaped like a tube.

00:43:21.640 | That's essentially what you look like early in development,

00:43:24.040 | not long after conception.

00:43:26.120 | And the front end of that churro grew and grew and grew,

00:43:30.040 | but you always maintained a hollow through that tube.

00:43:32.540 | That's why you have what are called ventricles,

00:43:35.000 | gaps or a space in your brain and spinal cord

00:43:38.200 | that run the length of your brain and spinal cord

00:43:39.960 | and fluid, cerebral spinal fluid

00:43:41.860 | and other things move through that space.

00:43:43.860 | We're going to return to the ventricles later.

00:43:45.340 | They are very, very important.

00:43:47.240 | They're just space filled with fluid, but they do a lot.

00:43:51.560 | Similarly, your digestive system

00:43:54.240 | starts with the tube at your mouth

00:43:56.120 | and of course goes down through your throat.

00:43:59.600 | And then you've got all the elements of the stomach

00:44:01.720 | and the intestines, and then it comes out the other end.

00:44:04.320 | So you are, but a series of different tubes,

00:44:06.320 | your vascular system, a series of other tubes.

00:44:08.600 | So your tubes.

00:44:10.100 | The way your digestive system works

00:44:14.720 | is to communicate to your brain about the status

00:44:18.120 | of the mechanical pressures along this tube.

00:44:21.080 | So within your stomach and your intestines, et cetera,

00:44:23.280 | and the chemical status of that tube

00:44:26.720 | at various portions within that tube

00:44:28.520 | to inform your brain about how your brain

00:44:32.920 | should control that tube.

00:44:34.260 | So let's start with the mechanical sensing of your gut.

00:44:39.060 | If you drink a lot of fluid or if you eat a lot of food,

00:44:44.120 | your gut will fill up, your stomach will fill up with food.

00:44:48.040 | Now it gets digested there.

00:44:50.240 | It gets digested elsewhere along your digestive tract too,

00:44:52.800 | of course, but it starts getting digested there

00:44:55.400 | because along this tube, you have a series

00:44:58.480 | of what are called sphincters,

00:44:59.680 | which basically are like little draw pulls.

00:45:01.920 | Have you ever had a laundry bag

00:45:03.160 | where it has a drawstring on it and you pull it

00:45:04.960 | and then it cinches shut and then you can open it again?

00:45:07.240 | That's what those are.

00:45:08.300 | Those are sphincter openings.

00:45:10.020 | And you have them in your throat.

00:45:12.300 | You have them along your digestive tract

00:45:14.720 | all the way to the end.

00:45:15.820 | Food will enter your gut.

00:45:20.060 | And if there's a lot of that food, pressure receptors,

00:45:23.280 | some of which are these piezo receptors,

00:45:25.680 | will communicate to the areas of your brain

00:45:28.320 | that are involved in feeding and will say,

00:45:30.760 | don't eat anymore.

00:45:31.900 | You don't need to consume anymore.

00:45:33.460 | Now, some people bypass that.

00:45:35.860 | I guess they have these like hotdog eating competitions.

00:45:38.480 | I'm always struck by how some of those people

00:45:41.220 | seem to be rail thin,

00:45:42.640 | but they actually train for those competitions

00:45:46.040 | by ingesting large volumes of water.

00:45:48.420 | Actually a very dangerous practice.

00:45:49.840 | You can actually kill yourself by drinking too much water

00:45:52.240 | and you can kill yourself by ingesting too much

00:45:54.720 | of anything really to expand your gut.

00:45:56.800 | Not a good practice, not a big fan of those competitions.

00:46:00.080 | But even if you're one of those people

00:46:02.040 | or you're the world heavyweight champion of them,

00:46:03.880 | they are informative toward what I'm talking about now,

00:46:07.120 | which is that as you expand the gut,

00:46:10.880 | a signal is sent by neurons,

00:46:12.700 | literally nerve cells that are in the gut to the brainstem,

00:46:16.700 | up to the areas of the brain that are involved in feeding.

00:46:18.900 | I did a whole episode on feeding.

00:46:20.520 | You can find on feeding metabolism and hunger.

00:46:22.960 | You're welcome to listen to that episode if you like.

00:46:25.740 | And it will shut down the neurons

00:46:27.440 | that drive the desire to put more stuff in your mouth.

00:46:30.840 | That thing that people say sometimes on,

00:46:32.920 | well, in this country frequently after Thanksgiving meal,

00:46:35.360 | I can't put another bite in my mouth.

00:46:37.360 | Literally they shut down some of the basic movements

00:46:40.460 | of the musculature to take another fork bite.

00:46:43.540 | I know it sounds crazy,

00:46:44.380 | but they can actually control your brain.

00:46:46.640 | So your gut is so full that it's controlling your brain

00:46:49.780 | such that this action of spooning food

00:46:52.320 | towards your mouth is actually inhibited.

00:46:54.260 | It's made more difficult or less likely to occur.

00:46:57.620 | It's incredible.

00:46:59.620 | The converse is also true.

00:47:01.440 | When these piezo receptors signal to the brain

00:47:03.580 | that the gut is empty,

00:47:05.320 | independent of your need, your actual need for food,

00:47:08.400 | there's a signal that sent to your brain

00:47:10.520 | that says gut is empty and neurons get stimulated

00:47:13.400 | in areas like the arcuate nucleus

00:47:15.020 | and these areas of the hypothalamus, et cetera,

00:47:17.320 | that drive the desire to make this action to open the mouth

00:47:22.220 | and to put stuff in it, in particular food.

00:47:25.400 | So when you find yourself at the refrigerator

00:47:28.300 | or you find yourself almost manically

00:47:31.340 | trying to get food of different kinds,

00:47:32.660 | you're not even thinking about what you're eating

00:47:34.180 | because you're so hungry.

00:47:35.720 | In part, that's because the lack of food in your gut

00:47:38.220 | has sent that information to your brain

00:47:41.420 | and is driving particular fixed action patterns

00:47:44.620 | that are associated with eating.

00:47:45.700 | In fact, one of the first things children learn how to do

00:47:47.900 | is open their mouth when something is presented to it.

00:47:50.420 | And then they learn how to move a spoon or a fork.

00:47:54.060 | They're not very good at it.

00:47:54.900 | First, they get all over the place,

00:47:56.020 | but eventually they get good at it,

00:47:57.540 | or at least most people get good at it.

00:47:58.620 | If you watch how people eat,

00:48:00.140 | it's kind of very variable out there.

00:48:02.860 | In any event, this is a purely mechanical phenomenon.

00:48:07.960 | And this purely mechanical phenomenon

00:48:09.620 | is driving our brain to drive certain behavior.

00:48:12.880 | You can get better at registering sense of fullness

00:48:16.740 | or lack of fullness in a very particular way.

00:48:20.420 | Some people have a very keen sense

00:48:22.640 | of how full or empty their stomach is.

00:48:25.080 | So if you've eaten anything,

00:48:26.740 | even if it's a small volume of food

00:48:28.220 | in the last hour to three hours,

00:48:31.200 | it's actually a worthwhile practice to take a few moments,

00:48:33.880 | maybe 10, 20 seconds,

00:48:35.420 | and actually just try and concentrate on sensing

00:48:38.900 | the neurons in your gut and how full you are.

00:48:41.040 | Like for instance, I ate a few hours ago,

00:48:43.060 | then I had a little snack about 30 minutes ago or so,

00:48:47.280 | and my gut feels neither terribly full nor terribly empty.

00:48:51.260 | It's kind of, I would put it at kind of like 30, 40%, okay?

00:48:56.000 | So by just taking conscious awareness

00:48:59.560 | of how full or empty our gut is at various times,

00:49:02.520 | between meals, after a meal, before a meal,

00:49:06.780 | you can very quickly develop a sense

00:49:09.560 | of how full or empty you are.

00:49:11.060 | Now, what's the consequence of that?

00:49:12.760 | The consequence of that is actually rather interesting.

00:49:14.840 | It's been shown that the consequence of that

00:49:16.400 | is actually that you can better override

00:49:18.820 | the signals of these piezo receptors

00:49:21.000 | and gut fullness or emptiness.

00:49:23.160 | So for those of you that find that you eat

00:49:24.900 | kind of compulsively or non-consciously

00:49:28.160 | or subconsciously, I should say,

00:49:30.120 | you probably have to be conscious enough to be awake to eat,

00:49:32.520 | but subconsciously, you just find yourself eating,

00:49:34.660 | and here I'm describing myself.

00:49:36.160 | I'm a drive-by blueberry eater.

00:49:38.040 | If there's a bowl of blueberries,

00:49:39.880 | every time I walk past it,

00:49:41.000 | I sort of have to grab a handful of them

00:49:42.320 | and pop them in my mouth.

00:49:43.760 | But if you develop this sense of how much mechanopressure,

00:49:48.060 | it's not really a word,

00:49:48.900 | but how much mechanosensation is in your gut,

00:49:52.200 | very quickly you can learn to override that.

00:49:54.980 | You might ask, why would I want to be able to override

00:49:57.680 | whether or not my stomach is empty or my stomach is full?

00:50:00.320 | Well, there are many reasons to want to do that.

00:50:03.040 | Many people right now are interested

00:50:04.640 | in so-called intermittent fasting.

00:50:06.200 | They're doing fasts of anywhere from 12 to 16 hours

00:50:09.060 | every 24-hour cycle.

00:50:10.460 | That's actually what my practice is.

00:50:12.080 | I do that on a regular basis.

00:50:13.260 | Sometimes, yeah, I eat breakfast,

00:50:14.400 | but normally I push breakfast out till about 11 or noon

00:50:16.860 | or sometimes a little later.

00:50:18.060 | Some people are doing longer fasts,

00:50:19.580 | and there are really wonderful data

00:50:21.560 | published in excellent journals

00:50:23.360 | from my colleague Sachin Panda at the Salk Institute

00:50:27.840 | of Biological Studies,

00:50:28.920 | and of course from other laboratories

00:50:30.440 | showing that intermittent fasting

00:50:32.520 | can and will have some positive health effects

00:50:35.200 | on things like liver health and brain health

00:50:37.920 | and other aspects of health.

00:50:39.680 | Whether or not it's the best form of dieting

00:50:41.780 | for the sake of losing weight, that's very controversial,

00:50:44.320 | but it's clear that having a period of fasting

00:50:47.360 | every 24 hours or perhaps even longer from time to time

00:50:51.220 | can be beneficial because it stimulates what's called

00:50:53.540 | autophagy, the clearing away or the body's ability

00:50:58.340 | to eat certain dead cells, so-called senescent cells.

00:51:01.540 | And for many people, they struggle with fasting

00:51:04.740 | because they feel they have a very keen sense

00:51:07.480 | of their stomach being empty,

00:51:09.500 | and they feel as if they have to eat.

00:51:11.540 | And in a kind of counterintuitive way,

00:51:13.980 | there's some data that indicate that being able to sense

00:51:16.340 | whether or not your gut is full or empty

00:51:17.940 | and just the knowledge that that's communicating information

00:51:21.060 | to your brain about whether to not to eat or not.

00:51:24.220 | Just that awareness, that understanding

00:51:26.780 | allows them to override the signal.

00:51:28.380 | They think, oh, you know,

00:51:29.220 | I'm not actually in need of nutrients right now.

00:51:31.500 | It's just that my stomach is empty

00:51:33.460 | and these piezo receptors and some other ones

00:51:36.500 | that I'll tell you about in a moment

00:51:38.260 | are signaling to my brain that it's empty.

00:51:40.260 | I don't actually need food.

00:51:41.620 | It's just that my brain is reacting to the fact

00:51:45.020 | that my gut is deflated, so to speak, or is smaller,

00:51:48.780 | doesn't have food in it.

00:51:50.380 | So there are other ways

00:51:51.520 | that our guts communicate with our brain.

00:51:53.380 | It's not just our stomach talking to our brain.

00:51:55.640 | It's also our intestines talk to our brain.

00:51:58.400 | The Lieberle's lab, the guy's name is Steven Lieberle's.

00:52:02.900 | He runs a lab at Harvard Medical School,

00:52:04.420 | his terrific lab, does excellent work

00:52:06.300 | on gut brain communication

00:52:07.760 | and other aspects of viscera brain communication.

00:52:10.740 | They discovered a category of neurons

00:52:13.260 | called the GLP-1R neurons.

00:52:15.340 | These are neurons that are basically in your neck.

00:52:19.660 | I mean, they're part of the nervous system,

00:52:20.660 | but they can be found near your neck.

00:52:23.420 | And those neurons send little wires down

00:52:26.220 | into the intestines and deep into the stomach,

00:52:31.140 | but mostly into the intestines,

00:52:33.720 | and they sense stretch of your intestines.

00:52:36.660 | So this is pretty wild.

00:52:37.780 | These neurons sense how stretched out your intestines are

00:52:40.340 | and how fast things are moving through your intestines,

00:52:42.740 | slow or fast, or if there's nothing there.

00:52:44.700 | And then those neurons send another branch.

00:52:47.140 | So they have a branch in one direction,

00:52:48.620 | senses what's going on in your intestines,

00:52:50.340 | and they have another branch that goes up from your neck

00:52:53.040 | into your brain to either trigger the desire to eat more

00:52:56.140 | or just stop eating.

00:52:57.680 | So these are really, really cool neurons,

00:52:59.060 | and they're basically stretch receptors.

00:53:00.420 | They look a lot like the piezo receptors

00:53:02.180 | that we talked about before.

00:53:03.660 | So these GLP-1R neurons are sensing stretch,

00:53:06.820 | so purely mechanical sensing.

00:53:09.140 | And in addition to that,

00:53:10.860 | the Lieberle's lab discovered neurons

00:53:13.500 | that detect nutrients themselves.

00:53:16.040 | Now, the main reason why we need to eat

00:53:18.580 | is to bring nutrients into our body.

00:53:21.580 | And there is another set of neurons,

00:53:23.980 | those are called GPR-65 neurons,

00:53:25.700 | if you want to know that you don't have to remember that,

00:53:28.060 | that do the same thing in terms of their connections.

00:53:30.900 | They send connections down into the intestines

00:53:32.720 | and into the gut, into the stomach,

00:53:34.780 | but mostly into the intestines,

00:53:35.980 | and then send that information back up to the brain

00:53:37.840 | as to whether or not there are certain kinds of nutrients

00:53:41.020 | in our digestive tract.

00:53:42.100 | Now, these neurons are the ones to pay attention to

00:53:44.320 | if we're talking about chemical signaling.

00:53:46.340 | And in the next couple of minutes,

00:53:48.180 | I'm going to tell you about how you can understand hunger

00:53:52.780 | and how to modulate your hunger for the right foods,

00:53:55.840 | in fact, for healthy foods.

00:53:58.220 | The way this is done is by leveraging the activity

00:54:02.360 | of these GPR-65 neurons,

00:54:04.620 | these neurons that sense nutrients, okay?

00:54:08.040 | They're telling your brain what's in your gut

00:54:10.460 | and intestines.

00:54:11.520 | And you have another set of neurons

00:54:13.180 | that were discovered by another guy.

00:54:14.780 | He's out at Duke University.

00:54:16.300 | His name is Diego, excuse me, Diego, Diego Borges.

00:54:20.820 | He's a wonderful scientist.

00:54:22.580 | He has a degree in nutrition, but also in neuroscience.

00:54:26.020 | And he found that there are neurons that line the gut,

00:54:28.740 | and those neurons, in collaboration with these GPR-65 neurons

00:54:33.260 | are sensing for three things, okay?

00:54:35.780 | So we say nutrients, which nutrients are they looking for?

00:54:38.500 | What are these neurons paying attention to?

00:54:40.380 | Well, these neurons are activated

00:54:41.940 | by the presence of fatty acids,

00:54:44.820 | in particular, omega-3 fatty acids,

00:54:47.740 | sorts of things that come from fatty fish, fish oil, krill,

00:54:51.260 | certain kinds of animal and plant substances.

00:54:56.260 | You can look up what has a lot of omega-3s.

00:54:59.060 | And those omega-3s make these neurons fire electrically

00:55:02.300 | like crazy up to the brain

00:55:04.020 | and make you want to eat more of those things,

00:55:06.380 | but it turns out in pretty appropriate levels.

00:55:09.020 | These neurons also respond to amino acids.

00:55:12.500 | So when you eat a food, it's broken down in the gut.

00:55:15.500 | Actually, the way it's broken down in the gut

00:55:16.660 | is kind of interesting.

00:55:17.600 | Your gut basically cinches off a sphincter up top,

00:55:20.920 | cinches off a sphincter below it when there's food there.

00:55:23.980 | And then you have a series of smooth muscles

00:55:27.420 | that tumble the food and literally physically break it down.

00:55:31.020 | And then of course,

00:55:31.860 | enzymes come in and start digesting the food.

00:55:33.900 | And we're going to talk about digestion

00:55:35.300 | and how that's communicated to the brain in a moment.

00:55:37.260 | And for those of you with any autoimmune issues

00:55:39.340 | or digestive issues,

00:55:40.920 | this is going to be a very important conversation.

00:55:43.140 | But meanwhile, there are these neurons in the gut.

00:55:46.220 | And as these fatty acids float out of the digested food,

00:55:49.300 | so literally fat molecules,

00:55:51.700 | and as amino acids are coming from the proteins

00:55:55.920 | as they're digested in the gut,

00:55:57.960 | and as a third food item,

00:56:00.000 | sugars are coming from the foods that we eat.

00:56:03.320 | These neurons will fire a lot to the brain that says,

00:56:06.140 | "Hey, whatever you're doing up there, do more of it."

00:56:09.480 | Now the sugars are a little bit cryptic

00:56:11.660 | because when I say sugars, or I say amino acids,

00:56:14.420 | or I say fatty acids, this has nothing to do with taste.

00:56:19.420 | In fact, beautiful experiments have been done

00:56:21.660 | by the Borges lab and by other labs showing

00:56:23.980 | that even if you numb the mouth,

00:56:26.900 | even if you gavage, which is a really just a,

00:56:29.260 | it's a fancy word for basically tube feeding,

00:56:32.020 | you put a tube down in the gut,

00:56:33.140 | you just deliver the food to the gut

00:56:34.340 | so you get no opportunity to taste it.

00:56:36.340 | Sounds pretty awful.

00:56:37.460 | If you force feed by gavage, or you numb the mouth,

00:56:41.060 | these neurons don't care about the mouth,

00:56:43.680 | they only care about the nutrients coming from these foods,

00:56:46.080 | and then they signal to the brain,

00:56:47.380 | "Hey, do that thing, do that thing where you lift

00:56:50.320 | that object we call a fork or a spoon,

00:56:52.400 | do that thing where you drink the milkshake,

00:56:54.440 | do that thing where you move your mouth like this,

00:56:56.560 | not talking, but do that thing where you swallow."

00:56:58.980 | So that's how the nutrients in our gut control us,

00:57:02.020 | and this is why for people

00:57:03.240 | that experience extreme sugar cravings,

00:57:05.800 | or even mild sugar cravings,

00:57:07.580 | replacing those foods with foods

00:57:09.420 | that have high levels of omega-3 or amino acids

00:57:12.860 | can reduce sugar cravings,

00:57:14.220 | and I've talked about this on a previous episode,

00:57:16.640 | but if you didn't catch it, no big deal,

00:57:17.980 | I'll tell you right now that for many people,

00:57:20.720 | the solution to sugar cravings is to ingest a small amount,

00:57:23.800 | maybe a teaspoon or so, of an amino acid called glutamine,

00:57:27.080 | and if you have really extreme sugar cravings,

00:57:30.660 | you can even mix that glutamine with a full fat cream,

00:57:33.980 | which actually makes it taste pretty darn good,

00:57:35.580 | and you drink that anytime you have a sugar craving,

00:57:37.980 | just a sip or two of that,

00:57:39.160 | and what you find is that the sugar cravings disappear

00:57:40.940 | because you're basically giving fat and amino acids

00:57:44.280 | to those neurons in the gut and in the intestine

00:57:46.980 | that signal to the brain that you want more.

00:57:49.120 | Now, this doesn't give you a kind of runaway hunger

00:57:51.160 | for full fat cream,

00:57:52.340 | although it will say when I was in high school

00:57:54.480 | for various reasons,

00:57:56.240 | but mostly 'cause I liked the way it tastes,

00:57:57.940 | I was using half and half in my cereal,

00:57:59.900 | and I was waking up in the middle of the night

00:58:00.980 | and drinking half and half,

00:58:01.940 | and that stuff tastes pretty darn good

00:58:03.220 | once you get used to the high fat content,

00:58:05.000 | not something I do now,

00:58:06.740 | but the point is these neurons don't really know taste,

00:58:11.400 | they only know nutrients,

00:58:12.780 | and so you can work with that system.

00:58:14.300 | If you crave sugar,

00:58:15.760 | and I do believe that most, if not all of us,

00:58:18.060 | should be trying to limit, if not eliminate,

00:58:20.300 | simple sugars as much as possible most of the time,

00:58:23.860 | then things like glutamine,

00:58:26.220 | things like high omega-3 foods, et cetera,

00:58:29.740 | maybe even want to supplement with fish oil

00:58:31.820 | or something similar to get omega-3s,

00:58:33.500 | there are other reasons for wanting to do that too,

00:58:35.380 | can be very beneficial,

00:58:36.460 | and here's what we're talking about is interoception.

00:58:40.320 | It's your ability to sense your inner real estate,

00:58:43.380 | but in this case by way of chemical signaling,

00:58:45.860 | not by way of mechanical signaling.

00:58:47.900 | So now I'd like to talk about another aspect

00:58:51.100 | of gut chemistry that has profound effects on the brain

00:58:55.580 | as well as on the immune system,

00:58:57.340 | and for those of you with autoimmune conditions

00:58:59.760 | or for those of you that know people

00:59:01.600 | with autoimmune conditions,

00:59:03.140 | this is going to be a very important discussion.

00:59:06.080 | Your gut needs to maintain a certain level

00:59:08.640 | of acidity or alkalinity.

00:59:11.100 | For those of you without any chemistry background,

00:59:14.260 | basically the low numbers on the pH scale,

00:59:17.020 | that means more acidic.

00:59:18.400 | The higher the numbers, more alkaline.

00:59:21.320 | So more alkaline means more basic and acidic means acidic,

00:59:25.380 | and it has to do with the number of hydrogen atoms

00:59:28.080 | and all this other stuff,

00:59:28.920 | you don't need to worry about that right now.

00:59:30.680 | We're not going to pH your gut right now,

00:59:32.060 | but we are going to talk about the pH of your gut.

00:59:34.200 | Your gut needs to be more acidic

00:59:36.140 | than essentially all other tissues of your body

00:59:38.320 | in order to function properly.

00:59:39.900 | Bacteria thrive in alkaline conditions.

00:59:44.440 | I think this is important for people to understand.

00:59:46.140 | People are always thinking,

00:59:46.980 | oh, you should be more alkaline, being acidic,

00:59:49.380 | that almost sounds like being inflamed.

00:59:52.380 | Well, it's a complicated discussion,

00:59:54.300 | but I think the semantics can be confusing sometimes.

00:59:56.940 | You want your gut to be acidic.

00:59:59.340 | You may ask, well, why are people taking anti-acids?

01:00:02.540 | Well, those anti-acids are there for a particular purpose

01:00:05.680 | to essentially combat acid reflux,

01:00:08.660 | which is the sending up of stuff in the gut

01:00:12.520 | towards the esophagus,

01:00:13.620 | and it can cause heartburn and things of that sort.

01:00:16.340 | And the way that anti-acids work

01:00:19.600 | is they essentially cause the sphincters

01:00:21.900 | above the gut to cinch shut,

01:00:24.060 | but they really are only dealing with a symptom,

01:00:26.300 | not the cause.

01:00:27.740 | So rewind about 10, 20 years ago,

01:00:31.460 | the discussion about gut acidity

01:00:33.440 | was quite a bit different than it is now

01:00:35.160 | in the scientific and medical literature.

01:00:36.980 | In fact, for many years,

01:00:38.860 | long before I'm going to say it here,

01:00:41.500 | people have been saying that it's important

01:00:44.020 | to maintain proper acidity of the gut,

01:00:47.300 | but the science and medical professions

01:00:50.020 | sort of looked at that as a kind of a scants,

01:00:52.380 | like, you know, what's going on there?

01:00:53.820 | I don't know that there's any evidence

01:00:55.160 | that that's actually true.

01:00:56.340 | There are communities of people that were prescribing,

01:00:58.980 | or I should say,

01:00:59.820 | recommending that people take hydrochloric acid, HCL,

01:01:03.040 | and adjusting gut acidity that way,

01:01:05.540 | and it was kind of frowned upon.

01:01:06.860 | Now, in looking over the peer-reviewed literature,

01:01:09.360 | it's clear that this business

01:01:10.940 | of trying to make the gut a little more acidic

01:01:12.820 | is actually one way in which people treat

01:01:15.400 | or try and ameliorate acid reflux.

01:01:18.940 | So it's kind of counterintuitive,

01:01:20.100 | increasing acidity in the gut

01:01:21.860 | to try and reduce acid reflux.

01:01:23.780 | I thought you're supposed to take antacids.

01:01:25.140 | Well, the field has shifted quite a bit,

01:01:27.680 | and so we're going to review what it is

01:01:29.300 | to maintain the chemistry of the gut

01:01:32.320 | at a slightly more acidic level,

01:01:34.600 | or a more acidic level, I should say,

01:01:36.440 | because it turns out that there are a number of things

01:01:38.700 | that are in gut, I just call it what it is,

01:01:41.280 | it's gastric juice, sounds kind of gross,

01:01:43.600 | but gastric juices are actually powerful modulators

01:01:47.480 | of brain state.

01:01:48.640 | Put differently, one of the best things that you can do

01:01:52.540 | to have a healthy brain, a well-functioning brain,

01:01:54.700 | and a healthy and well-functioning body

01:01:56.300 | is to maintain proper gut chemistry,

01:01:59.400 | and that's basically accomplished

01:02:01.420 | by getting the right level of acidity

01:02:03.620 | and alkalinity in your gut.

01:02:05.380 | Now, this is not quack pseudoscience,

01:02:08.380 | this is not based on cleanses or anything of that sort.

01:02:11.500 | What we're going to talk about now are peer-reviewed data

01:02:14.380 | in very high quality journals like the journal Cell,

01:02:17.780 | which is one of the three apex journals,

01:02:19.380 | Science, Nature, Cell,

01:02:20.740 | and journals of that sort that point to the gut microbiome

01:02:24.220 | and its relationship to acidity of the gut

01:02:26.460 | and how the gut microbiome

01:02:28.260 | can help enhance autoimmune function

01:02:32.780 | and various other aspects of brain and body health.

01:02:35.220 | So within all the mucosal line tissues of our body,

01:02:39.460 | we have what are called microbiota,

01:02:41.740 | little microorganisms that we didn't make

01:02:43.980 | that actually come from our environment or our food

01:02:47.020 | and live inside us.

01:02:50.100 | And there are good microbiota and there are bad microbiota.

01:02:53.560 | Whether or not we have good microbiota or bad microbiota

01:02:59.140 | depends on one thing.

01:03:01.140 | And that one thing is how acid or alkaline

01:03:05.200 | the given mucosal tissue is.

01:03:07.180 | So we actually have a microbiome in our nose.

01:03:11.700 | And just as a very brief aside,

01:03:13.240 | because I'd be remiss if I didn't say this,

01:03:15.860 | if you emphasize nasal breathing most of the time,

01:03:19.080 | except when speaking or eating,

01:03:20.680 | and if you downplay mouth breathing,

01:03:24.240 | meaning you refrain from mouth breathing,

01:03:25.920 | especially in sleep,

01:03:27.340 | you improve the nasal microbiome.

01:03:32.020 | It gets better at fighting off infections.

01:03:35.700 | This was shown in a beautiful paper

01:03:37.140 | published in Cell Reports last year.

01:03:39.600 | And that paper I should mention was performed in humans.

01:03:43.140 | So you got a microbiome in your nose

01:03:44.960 | and by nasal breathing most of the time,

01:03:46.540 | not all the time,

01:03:47.380 | 'cause there can be times when you need to breathe

01:03:48.460 | through your mouth for whatever reason,

01:03:49.760 | hard exercise or eating or speaking,

01:03:52.320 | but by breathing through your nose most of the time,

01:03:54.400 | you are creating an additional layer of immune defense

01:03:58.580 | against particles that could get you sick.

01:04:00.620 | Whereas when you mouth breathe,

01:04:02.000 | you are taking down a layer of defense

01:04:04.000 | and you're putting yourself more at risk of infection.

01:04:06.120 | This is what this paper shows.

01:04:07.620 | You also have a gut microbiome that is in your throat,

01:04:14.480 | in your stomach and in your intestines.

01:04:18.320 | And that gut microbiome is extremely powerful

01:04:20.920 | in regulating your mood and your immune function.

01:04:24.720 | Now, this is not something that you can sense directly.

01:04:27.160 | You don't know when you have a bunch of good microbiota

01:04:30.600 | or a bunch of bad microbiota

01:04:32.300 | because you can feel them moving around in there.

01:04:33.940 | Actually, that would be pretty awful.

01:04:35.160 | That would be pretty creepy feeling.

01:04:37.100 | Rather, according to whether or not your gut is alkaline

01:04:41.520 | or acidic in the appropriate ways,

01:04:43.820 | you will populate your gut with the appropriate microbiota.

01:04:48.920 | So you want your stomach to be pretty acidic,

01:04:52.920 | but other elements of your digestive tract

01:04:55.240 | are going to be more pH.

01:04:57.180 | And basically there's a gradient,

01:04:58.880 | meaning there's a low to high pH gradient along the gut.

01:05:03.880 | You don't have to know what the pH

01:05:05.720 | should be at any one given point,

01:05:08.100 | because you're not going to go and put microbiota

01:05:10.400 | at one location and not another.

01:05:12.440 | What you essentially want to do is create an environment

01:05:16.020 | where the proper microbiota can thrive.

01:05:18.680 | Because when you do that,

01:05:20.440 | you greatly decrease what are called inflammatory cytokines.

01:05:24.500 | So these are things that are secreted

01:05:25.920 | both by cells within the body and cells within the brain

01:05:29.420 | to impact brain health and brain function and bodily health.

01:05:33.020 | They go by a particular name.

01:05:34.140 | So there's something called TNF alpha,

01:05:36.340 | tumor necrosis factor alpha.

01:05:38.620 | It is inflammatory.

01:05:40.020 | It's not a good thing to have at elevated levels.

01:05:43.000 | You have something called interleukin-6, IL-6.

01:05:45.900 | Also causes inflammation, causes damage to tissues.

01:05:48.820 | Not a good thing to have for elevated

01:05:51.700 | for long periods of time.

01:05:53.180 | And then you have anti-inflammatory cytokines,

01:05:55.420 | things like interleukin-10, which reduce inflammation.

01:05:57.940 | And there are hundreds of these,

01:05:59.620 | if not thousands of these different cytokines,

01:06:01.820 | some of which promote inflammation,

01:06:03.540 | some of which reduce inflammation.

01:06:06.100 | The simple way to adjust these things in the proper ratios

01:06:11.100 | is to adjust your gut microbiome.

01:06:13.020 | The best way to adjust your microbiome

01:06:14.900 | is to ingest certain types of foods.

01:06:17.540 | So there is a beautiful literature on this now,

01:06:20.060 | but the most important literature

01:06:21.680 | is the one that I referred to

01:06:23.580 | at the beginning of this episode,

01:06:25.260 | which is what to ingest and what not to ingest

01:06:29.060 | in terms of foods in order to create

01:06:31.340 | the best conditions in your gut

01:06:33.620 | so that you can create the best conditions

01:06:35.220 | in your brain and body.

01:06:36.380 | There was a study done by my colleague Justin Sonnenberg

01:06:40.620 | at Stanford School of Medicine.

01:06:43.180 | Justin's actually my upstairs neighbor

01:06:45.620 | in the building at Stanford where I work.

01:06:48.380 | And they explored how different foods

01:06:51.760 | or different diets, I should say,

01:06:53.760 | impact the gut microbiome and inflammatory markers.

01:06:56.660 | And this is a beautiful study

01:06:57.780 | because it was done in hundreds of human patients.

01:07:00.660 | These actually weren't patients that were sick.

01:07:02.460 | I should say human subjects that were otherwise healthy

01:07:06.280 | from a huge variety of backgrounds.

01:07:08.460 | So you had men, you had women,

01:07:09.720 | you had people of different races, different, yeah,

01:07:12.260 | ethnicities, you had a huge range of backgrounds

01:07:14.600 | and they tracked all of that.

01:07:16.140 | And what they did is they explored two types of diets.

01:07:19.100 | One is a high fiber diet.

01:07:21.140 | So dietary fibers are non-digestible

01:07:24.860 | or only partially digestible carbohydrates typically.

01:07:27.940 | And they compared that to diets that were unchanged

01:07:30.620 | except for the inclusion of a few to a few more servings

01:07:35.140 | of fermented foods each day, things like sauerkraut,

01:07:37.940 | things like kimchi.

01:07:38.960 | They even explored, sounds pretty disgusting to me,

01:07:41.100 | but who knows, I've never tried it,

01:07:42.180 | which is fermented cottage cheese.

01:07:44.620 | And what they found was that after initial period

01:07:47.420 | of a few weeks where they had people

01:07:49.580 | either eat a lot of fiber

01:07:51.100 | or eat one or two servings of fermented foods,

01:07:54.660 | they had those people ramp up their ingestion

01:07:57.100 | of either fiber or fermented foods.

01:07:58.700 | So they kind of ease them into it.

01:08:00.160 | So they went baseline, then ramp up

01:08:02.380 | to the point where they were ingesting

01:08:03.940 | four or five servings of fiber

01:08:05.780 | or of fermented foods per day, which sounds like a lot,

01:08:10.380 | but for fermented foods,

01:08:11.380 | that would be four or five tablespoons

01:08:14.180 | of sauerkraut or kimchi.

01:08:16.140 | It's not quite, it's not like huge platefuls

01:08:18.100 | of fermented foods.

01:08:20.100 | And then they looked at a number of things.

01:08:22.420 | They looked at the proteome,

01:08:23.700 | which is a kind of like looking at the genome,

01:08:25.380 | but a bunch of proteins that are made in the body.

01:08:27.620 | And they did this by fecal samples, by stool samples.

01:08:30.860 | And they did this by blood draw, which is great.

01:08:32.980 | It's a real power of this study.

01:08:34.380 | In fact, the most comprehensive study that I'm aware of.

01:08:37.580 | By looking at these different tissues

01:08:39.340 | across long periods of time,

01:08:40.960 | so many, many weeks,

01:08:42.220 | and then returning people to the diet that they were on

01:08:46.160 | before they went into the study,

01:08:48.120 | they were able to establish in a causal way

01:08:51.380 | how ingesting fiber or fibrous foods

01:08:54.560 | versus ingesting these fermented foods on a daily basis

01:08:57.420 | could impact the gut microbiome

01:08:59.060 | and many, many inflammatory markers

01:09:02.240 | and many, many markers of immune function

01:09:05.900 | and autoimmune function.

01:09:07.920 | And the takeaway message from this study

01:09:10.020 | is that the fermented foods

01:09:11.520 | far outperformed the high fiber diet.

01:09:15.220 | In fact, the high fiber diet in some people was beneficial

01:09:18.440 | and in other people caused issues with inflammation.

01:09:22.300 | This is very different than what I was taught growing up

01:09:25.240 | and what many of us were taught.

01:09:26.840 | Interestingly, they also observed

01:09:29.780 | that people that ate the high fiber diet

01:09:31.920 | had increases in certain enzymes

01:09:34.560 | that lend themselves to better digestion of carbohydrates.

01:09:38.860 | And I think there's an important insight to come from this.

01:09:41.300 | Nowadays, we kind of live in the age of extremes

01:09:43.320 | where people seem to either want to be carnivore,

01:09:45.600 | like never ingest a vegetable.

01:09:47.260 | I hear they don't even, they're like allowed pepper,

01:09:49.300 | but they're not even allowed, you know,

01:09:51.580 | sauerkraut or something like very extreme

01:09:53.900 | or pure plant-based, pure vegan,

01:09:56.700 | or pure, so essentially pure carbohydrate

01:09:59.020 | or pure animal protein, very extreme.

01:10:01.520 | I'm an omnivore.

01:10:02.580 | I like to eat a mixture of different things

01:10:05.100 | at different times of days, but very extreme.

01:10:07.940 | But this is interesting because what these data show

01:10:10.460 | is that perhaps ingesting a high carbohydrate,

01:10:13.960 | high fiber diet, which is really what these,

01:10:16.020 | the high fiber condition really was,

01:10:18.440 | actually makes people better at digesting carbohydrates.

01:10:22.500 | This may explain why people who are used to a kind of

01:10:25.500 | more paleotype or carnivore type diet

01:10:28.860 | might eat carbohydrates and say,

01:10:30.340 | "Oh, that doesn't work for me. I don't feel good."

01:10:32.380 | It might also explain why people who predominantly

01:10:34.820 | eat plant-based foods and carbohydrate foods

01:10:37.500 | will try eating meat as an experiment

01:10:40.040 | or because they lost a bed or whatever it is,

01:10:41.980 | and they'll do, or desperation or they'll do that.

01:10:44.980 | And then they'll say, "Oh, I don't feel good

01:10:46.740 | when I eat meat."

01:10:47.780 | How good you feel, it seems,

01:10:50.820 | how well you can utilize that food

01:10:53.060 | and how much of that food you crave

01:10:55.540 | may be determined, in fact, it appears is determined

01:10:59.300 | by your food eating history, the types of food you eat.

01:11:02.580 | And I think this might explain some of the divide

01:11:05.680 | and hopefully might bridge some of the chasm

01:11:07.860 | between these different groups that are saying

01:11:09.500 | it should be one way or it should be another.

01:11:11.780 | But at the core of the study was the bigger message.

01:11:15.660 | The bigger message is that all of us

01:11:18.420 | should be ingesting on a regular basis, daily basis,

01:11:22.240 | two to four servings of fermented foods of different kinds.

01:11:25.240 | And why I say that is because

01:11:27.800 | the inflammatory markers went down,

01:11:30.060 | the markers of autoimmune disruption went down

01:11:35.060 | and the chemistry of the gut, therefore,

01:11:38.180 | was adjusted in the appropriate ways.

01:11:40.260 | Now, it's not to say that high fiber is bad

01:11:42.220 | or that fiber is bad, I don't want people to confuse this,

01:11:44.860 | but even though this is a discussion about interoception,

01:11:47.500 | about sensing the self, this is a subconscious mechanism

01:11:51.420 | by which the gut communicates to many, many organs,

01:11:54.640 | including the brain.

01:11:55.620 | And it's been shown in other studies,

01:11:57.980 | also in quality peer review journals,

01:12:00.060 | that when the correct gut microbiota are present

01:12:04.400 | and these inflammatory markers are reduced,

01:12:07.200 | cognition improves, so ability to focus,

01:12:10.000 | ability to sleep, ability to ward off infection

01:12:12.560 | and wound healing all enhanced.

01:12:14.460 | In fact, even in autism spectrum disorder,

01:12:17.500 | in people that struggle with various mental conditions

01:12:20.880 | or disorders of the mind,

01:12:22.580 | improving the gut microbiome seems to have powerful effects

01:12:25.780 | on improving brain symptoms.

01:12:28.220 | Along the lines of autoimmunity,

01:12:30.080 | there are a number of conditions

01:12:31.940 | that we call autoimmune conditions,

01:12:35.040 | and we will do entire episodes about these going forward,

01:12:37.460 | but for people with so-called irritable bowel syndrome,

01:12:41.060 | for people with Crohn's disease,

01:12:42.540 | for people with leaky gut, Hashimoto's,

01:12:45.220 | which is a kind of an immune system self-attack

01:12:48.220 | on one's thyroid gland,

01:12:50.160 | and things like eczema, skin conditions,

01:12:53.020 | adjusting the gut microbiome has been shown to be useful

01:12:56.760 | in positively adjusting the symptoms of all of those.

01:13:01.180 | Will it fix those conditions entirely?

01:13:03.980 | Probably not.

01:13:04.820 | But can it have a significant positive impact on them?

01:13:07.800 | Probably yes.

01:13:09.760 | There is one thing that's worth mentioning in that list,

01:13:11.860 | which is leaky gut.

01:13:13.380 | What is leaky gut?

01:13:14.320 | Here we're talking about the guts.

01:13:15.320 | What is it to have a leaky gut?

01:13:17.140 | It sounds awful.

01:13:17.980 | It sounds like something sort of like leaking out

01:13:19.780 | the end of the tube and maybe that too, I don't know.

01:13:22.460 | But leaky gut is actually because your gut

01:13:26.140 | is not a tube that's continuous one cell,

01:13:29.460 | it's actually made up of many, many cells,

01:13:31.140 | and those cells form a barrier

01:13:33.900 | and they form what are called tight junctions.

01:13:36.260 | So if you have two cells and you want to create a fence

01:13:38.700 | out of those cells, you bind them together.

01:13:40.860 | The way that the body does this is to bind them together

01:13:43.140 | with what are called tight junctions.

01:13:44.500 | These are, they go by names like cloudins

01:13:46.460 | and things like that if you want to look them up.

01:13:48.180 | These tight junctions form a nice barrier

01:13:50.820 | like a cyclone fence that things can't get past,

01:13:53.740 | but like a cyclone fence, only molecules of a certain size

01:13:56.940 | can go through those holes.

01:13:57.840 | So you're not going to pass a soccer ball

01:13:59.180 | through an intact cyclone fence, but you could pass,

01:14:02.180 | for instance, a feather through that fence.

01:14:04.740 | So leaky gut is when the conditions in the gut

01:14:09.340 | are too alkaline or the gut microbiota are off in the gut,

01:14:14.240 | meaning microbiota that like alkaline guts are living there

01:14:19.240 | and those tight junctions can't function

01:14:22.360 | at that particular pH

01:14:23.860 | and you create little holes in that fence.

01:14:26.660 | And then what happens is when you ingest foods,

01:14:29.660 | some of those foods literally leak out of the gut

01:14:32.220 | and into the extracellular space and into the bloodstream.

01:14:36.740 | And because foods include proteins

01:14:39.860 | and antibodies react to proteins,

01:14:44.540 | what ends up happening in leaky gut,

01:14:46.820 | and the reason we talk about it in autoimmune conditions

01:14:48.860 | is that you start developing antibodies

01:14:51.300 | to particular food proteins.

01:14:53.500 | And then people start feeling like they have food allergies

01:14:56.180 | and they do, they actually create particular food allergies.

01:14:59.220 | Now, one way to prevent leaky gut

01:15:00.860 | is to get the rest of the gut situation happy

01:15:03.420 | by ingesting the proper foods that we talked about before,

01:15:06.300 | ingesting fermented foods on a regular basis.

01:15:09.820 | The other is our old friend glutamine again.

01:15:13.220 | There are some data,

01:15:14.920 | and I should say it's a limited number of studies,

01:15:16.660 | showing that ingesting glutamine

01:15:18.820 | anywhere from one to three teaspoons per day

01:15:22.560 | can help alleviate leaky gut.

01:15:25.340 | Now, the mechanism for that still isn't clear

01:15:27.520 | whether or not it's adjusting pH

01:15:28.900 | or whether or not it's creating more favorable environment

01:15:32.860 | for the microbiota,

01:15:34.260 | but it is clear that supplementing with glutamine

01:15:36.620 | can in some people enhance,

01:15:39.220 | or I should say improve conditions of leaky gut.

01:15:41.940 | So that might be useful as well.

01:15:43.540 | And then the final thing about this

01:15:44.900 | that I want to talk about

01:15:45.740 | as we're talking about chemical sensing in the gut

01:15:48.660 | and how that impacts wellbeing is about gut acidity.

01:15:53.340 | And this, I confess is a little bit controversial.

01:15:56.500 | Some people are on board this, other people are not.

01:15:59.500 | And so I'd love your feedback on this.

01:16:01.420 | If you agree, please tell me.

01:16:03.420 | If you disagree, please tell me,

01:16:05.140 | but please tell me why you disagree in particular.

01:16:08.120 | Experience or data, although it's always better

01:16:10.940 | if you can point me towards peer reviewed studies.

01:16:13.420 | There is a practice that some people embrace.

01:16:16.060 | I'm not recommending people necessarily do this

01:16:17.900 | and you would definitely want to talk to your doctor,

01:16:19.740 | but where people have food allergies

01:16:22.060 | or they're having mood or autoimmune issues

01:16:24.460 | and they treat this,

01:16:27.220 | some people recommend treating this

01:16:28.500 | through the ingestion of HCL, hydrochloric acid tablets.

01:16:32.820 | Now, hydrochloric acid can burn you, right?

01:16:34.980 | Acids can burn you.

01:16:36.020 | They literally can melt away skin.

01:16:38.460 | You want to be very careful with acids of all kinds, truly.

01:16:43.020 | But hydrochloric acid is sold as in supplement form,

01:16:47.220 | in capsular pill form.

01:16:48.620 | And there is a practice of starting to ingest

01:16:51.300 | one or two hydrochloric acid tablets midway through a meal.

01:16:55.460 | And then what people will generally do

01:16:57.420 | is examine to see whether or not

01:16:58.740 | that improves their symptoms of indigestion,

01:17:02.580 | how it relates to mood, how it relates to wellbeing,

01:17:05.660 | how it relates to their sensation of their gut viscera.

01:17:08.200 | By changing the acidity,

01:17:09.500 | you also change the way that the gut communicates

01:17:11.400 | with the brain through the mechanisms

01:17:12.660 | we talked about before.

01:17:13.740 | And there are a growing number of people

01:17:15.900 | embracing these practices of taking HCL.

01:17:18.600 | It's often combined with other things.

01:17:21.100 | It's usually combined with an enzyme.

01:17:25.000 | And that enzyme is pepsin.

01:17:28.580 | So most of these supplements

01:17:31.420 | come in the form betaine HCL pepsin.

01:17:34.260 | And while they're not a cure-all,

01:17:36.740 | I certainly don't want to suggest that they're a cure-all,

01:17:39.500 | many people that have a hard time

01:17:41.140 | adjusting the pH of their gut

01:17:43.420 | and have a hard time adjusting the microbiota of their gut

01:17:46.060 | in the appropriate ways have benefited

01:17:48.020 | from taking these betaine HCL pepsin tablets

01:17:52.340 | or capsules during meals.

01:17:53.900 | And the general instruction is to start slow,

01:17:56.500 | to start with one or two,

01:17:57.660 | and then to find a level that you're comfortable with

01:17:59.820 | that doesn't create an excessive feeling of warmth

01:18:02.340 | in the stomach that doesn't throw off your digestion.

01:18:05.140 | So it takes a little bit of experimentation.

01:18:06.860 | Again, definitely talk to your healthcare provider

01:18:09.460 | before exploring this.

01:18:10.900 | But this has become a very common practice

01:18:13.820 | for people with autoimmune disorders

01:18:16.400 | and accessing the gut,

01:18:18.700 | because it is accessible by taking things,

01:18:21.440 | has also become a way in which people

01:18:23.880 | with various mental conditions

01:18:25.860 | are trying to adjust their mood and adjust their wellbeing.

01:18:29.400 | Along these lines, I do want to mention

01:18:31.600 | that there are studies that show

01:18:33.180 | that people that supplement with a lot of probiotics

01:18:37.840 | or even prebiotics can sometimes experience brain fog.

01:18:41.660 | This isn't discussed a lot

01:18:43.000 | and the data are a little all over the place,

01:18:45.100 | but it is worth thinking about.

01:18:47.140 | The goal here is not to create

01:18:50.060 | as many microbiota as possible.

01:18:52.040 | What you want is microbiota diversity.

01:18:55.200 | And I should mention this again

01:18:56.780 | in reference to the Sonnenberg study,

01:18:59.380 | which was what the high fiber diet does

01:19:02.580 | is it increases certain microbiota,

01:19:05.120 | but it limits their diversity.

01:19:07.440 | And what the fermented food diet does,

01:19:09.720 | or I should say the diet that includes

01:19:11.680 | regular ingestion of fermented foods, a few servings a day,

01:19:15.220 | is it increases microbiota diversity.

01:19:19.160 | Now, lack of microbiota diversity

01:19:21.780 | has a name in the medical profession.

01:19:23.760 | It's called dysbiosis and dysbiosis is bad.

01:19:26.560 | Dysbiosis is what you see

01:19:28.280 | when people are spending long periods of time on bed rest

01:19:31.880 | or when they've been chronically ill.

01:19:34.120 | And so here again,

01:19:35.580 | we're talking about creating a positive environment

01:19:39.120 | in the gut, either by adjusting acidity,

01:19:40.960 | maybe you explore the betaine HCL pepsin thing.

01:19:43.880 | I think if you have healthy digestion,

01:19:45.520 | if you feel like you have a good relationship to your gut

01:19:49.180 | and it has a good relationship to you,

01:19:50.540 | sort of a silly phrase because it is you and you are it,

01:19:53.440 | then I don't think there's any means

01:19:56.400 | or any need to pursue this.

01:19:58.360 | But if you don't, that might be one avenue to pursue.

01:20:01.120 | However, I think primary in all of this

01:20:03.240 | is the fermented food findings.

01:20:05.200 | And it's not just one study, it's many, many findings

01:20:08.000 | that now bring us to a place

01:20:09.320 | where a huge center of mass of data

01:20:11.180 | are pointing us in the direction of saying,

01:20:13.240 | ingest fermented foods on a regular basis.

01:20:16.480 | I should also mention that conditions like sarcopenia,

01:20:20.160 | which is the loss of muscle tissue as we age,

01:20:22.960 | has been shown to be offset by improving the gut microbiota.

01:20:26.720 | So while today is about interoception,

01:20:28.820 | we're talking about sensing,

01:20:30.100 | we're also talking about subconscious sensing.

01:20:32.240 | What are we talking about subconscious sensing?

01:20:33.800 | We're talking about subconscious sensing

01:20:35.840 | of the milieu of the body.

01:20:37.400 | When the milieu of the gut and the body is right,

01:20:40.700 | then the brain and the immune system function very well.

01:20:44.560 | And so this isn't something where you can sit back and say,

01:20:46.900 | oh, you know, I feel all those good microbiota in my gut.

01:20:50.320 | Or, oh no, those are bad microbiota.

01:20:52.440 | You can't do that.

01:20:53.320 | Unless you're going to take fecal samples and blood samples

01:20:57.000 | and analyze them with the extreme exhaustive nature

01:21:01.080 | that the Sonnenberg and other labs do,

01:21:03.240 | you're not going to get that kind of information.

01:21:04.720 | I know there are companies out there that do this

01:21:07.240 | and I don't want to knock on any of them,

01:21:09.320 | but I do want to emphasize that to do this right,

01:21:12.960 | to really analyze which cytokines you're making

01:21:15.600 | and which ones you're not,

01:21:16.600 | you really need to look at a huge number of them.

01:21:18.400 | And that requires large-scale proteomic and genomic

01:21:22.160 | and inflammatory marker screens.

01:21:24.960 | It's just not the kind of thing

01:21:26.240 | that most commercial enterprises can really provide

01:21:28.920 | to people in a way that they can interpret.

01:21:30.920 | Rather, this is a case where you can simply go

01:21:33.040 | to the effector, to the thing that can actually

01:21:34.800 | move the needle in the right direction for you.

01:21:36.880 | It's very clear that's fermented foods

01:21:38.480 | and that's keeping the stomach slightly more acid

01:21:41.680 | than one might think you would want to.

01:21:44.020 | So let's talk about barfing first.

01:21:46.440 | Barfing, AKA vomiting,

01:21:48.720 | is when the contents of your guts run in reverse,

01:21:53.220 | meaning when they go up from your stomach,

01:21:55.360 | sometimes even up from the intestines,

01:21:56.960 | even though that sounds horrible, it sometimes happens,

01:21:59.580 | up out the esophagus and mouth

01:22:02.160 | and onto whatever surface happens to be in front of you.

01:22:06.320 | It's a terrible thing, nobody likes to do it,

01:22:08.460 | but it's a very interesting aspect to our biology

01:22:11.520 | because it reveals a beautiful

01:22:14.600 | and absolutely fundamental relationship

01:22:16.640 | between our chemistry and our brain.

01:22:20.840 | So your brain is actually locked behind a gate

01:22:25.640 | and that gate is not your skull.

01:22:28.140 | That gate is the so-called blood-brain barrier.

01:22:31.200 | So just like your gut has these epithelial tight junctions,

01:22:34.520 | the things I talked about before,

01:22:35.800 | that provide a fence so things can't get through

01:22:38.760 | and get through and leaky gut,

01:22:40.840 | your brain has tight junctions that are very, very tight.

01:22:45.800 | It's absolutely fundamental that only certain molecules

01:22:49.600 | get across the blood-brain barrier and that others don't.

01:22:52.380 | And the reason for that is that most all,

01:22:55.520 | 99.9999% of your neurons do not regenerate.

01:23:00.520 | I don't care what you've read,

01:23:01.840 | especially in the news recently

01:23:03.000 | about how psychedelics cause neurogenesis

01:23:04.900 | because they don't, it's absolutely wrong.

01:23:07.640 | Psychedelics have effects on brain plasticity,

01:23:09.560 | but they have nothing to do with neurogenesis,

01:23:11.320 | at least no data support it.

01:23:13.120 | But because you can't make new neurons,

01:23:16.740 | you also can't damage the ones you've got

01:23:19.060 | or you shouldn't as much as possible.

01:23:20.800 | And that's why you have a blood-brain barrier or a BBB.

01:23:25.080 | So the BBB as it's called prevents substances

01:23:30.080 | from getting to the brain.

01:23:33.000 | However, like any fence,

01:23:36.140 | it is not always uniform along its length.

01:23:39.440 | And there are little spots within that fence

01:23:42.280 | where chemicals can sneak across to the brain.

01:23:45.700 | And through a beautiful design,

01:23:48.880 | I don't know anything about the design.

01:23:50.680 | As I always say, I wasn't consulted the design phase,

01:23:52.620 | so I'm not talking about any kind of intelligent design

01:23:55.060 | or anything, that is not the topic of this podcast.

01:23:57.320 | This is not a philosophy podcast,

01:23:58.920 | nor is it a religion podcast, it's a science podcast.

01:24:01.920 | But through a beautiful design of some sort,

01:24:04.460 | there are little holes in that fence

01:24:08.440 | and there are little neurons

01:24:10.080 | that sit right behind those holes.

01:24:12.040 | And those neurons sense what the chemistry of the blood is.

01:24:17.040 | So I'm guessing you probably didn't imagine

01:24:18.900 | that today's discussion about sensing the self

01:24:20.680 | would be sensing your own blood, but you do.

01:24:23.480 | There's a little area of your brain that's little indeed,

01:24:26.520 | but is very, very important called area postrema.

01:24:29.760 | P-O-S-T-R-E-M-A.

01:24:32.880 | An area postrema is an area of the brainstem

01:24:35.640 | that sits right next to another brain area

01:24:38.780 | called the chemoreceptor trigger zone.

01:24:41.880 | And when the contents in your bloodstream

01:24:45.060 | are of a particular kind,

01:24:47.520 | meaning when there are pathogens or it's too acidic,

01:24:51.920 | the neurons in area postrema

01:24:55.520 | and the neurons in the chemoreceptor trigger zone,

01:24:58.480 | the CTZ as it's called,

01:25:00.660 | trigger a bunch of motor reflexes in the abdominal wall

01:25:05.620 | that make you barf, okay?

01:25:09.740 | The feeling that you need to throw up

01:25:12.440 | is triggered by these neurons in the brainstem

01:25:14.280 | and those neurons in the brainstem are triggered

01:25:16.240 | by the presence of certain chemicals.

01:25:18.400 | And the reason why you don't have any blood brain barrier

01:25:20.920 | at that location is because postrema has to be there

01:25:23.920 | like a crossing guard,

01:25:25.300 | making sure that everything that's coming through the blood

01:25:28.060 | is okay and if it even senses just the tiniest bit

01:25:31.580 | that things are off, it's going to trigger that reflex.

01:25:35.180 | Now, the really interesting thing is that the neurons

01:25:37.280 | in area postrema respond to the chemistry of the blood,

01:25:41.440 | but they also will respond to our consciousness,

01:25:44.720 | to things that we think and things that we believe

01:25:47.160 | and even particular memories.

01:25:49.560 | This is why when certain people see vomit

01:25:53.060 | or see someone else vomit or even somebody else heaving

01:25:56.500 | as if they're going to vomit,

01:25:57.920 | they themselves feel as if they're going to vomit.

01:26:00.460 | I'm guessing there are probably even a few of you right now

01:26:03.000 | that feel like you might vomit.

01:26:04.840 | You might feel salivation in your throat,

01:26:07.520 | which is always a precursor to vomiting.

01:26:09.520 | Some people, the memory of or the thought of something

01:26:14.540 | like blood or vomit or use your imagination

01:26:17.640 | can actually trigger the vomit reflex.

01:26:20.480 | And that's because these neurons in area postrema

01:26:23.680 | are very sensitive to prior experience of interactions

01:26:27.520 | with negative things.

01:26:29.440 | So, and actually, as I'm saying this,

01:26:31.100 | I feel my gut kind of cramping up again.

01:26:32.720 | I don't vomit very easily, I'm not one of those,

01:26:36.100 | nor am I somebody who's never vomited.

01:26:39.520 | And here we are talking about my vomit history,

01:26:42.680 | but I think it's appropriate in this context.

01:26:45.720 | The neurons of area postrema are there basically

01:26:49.500 | to keep your whole system safe.

01:26:51.760 | And thank goodness they are because for instance,

01:26:54.960 | some people, unfortunately, they drink so much alcohol

01:26:58.560 | that they throw up.

01:26:59.400 | Have you ever wondered why that is?

01:27:00.560 | Well, it's because alcohol fundamentally is a poison.

01:27:04.160 | I'm not saying for age appropriate folks

01:27:06.600 | that ingesting alcohol is bad, this isn't a judgment call,

01:27:09.860 | but alcohol itself at excessive levels in the bloodstream

01:27:14.160 | triggers postrema to cause vomiting.

01:27:17.420 | So this is an example whereby memories, context,

01:27:23.180 | but also just the chemistry of our internal state

01:27:25.540 | is triggering behaviors that are very hardwired,

01:27:29.080 | they're very reflex driven.

01:27:30.420 | And why would it be that some people get more nauseous

01:27:33.720 | than others at a given level?

01:27:35.020 | Well, they'll have to do with alcohol tolerance.

01:27:37.060 | Some people have what's called a,

01:27:39.080 | we refer to as a stronger stomach or a stomach of steel.

01:27:42.560 | Other people, they throw up very easily

01:27:45.220 | if they don't feel well, or if they ingest anything

01:27:47.860 | that's just a little bit off.

01:27:49.400 | From a purely adaptive standpoint,

01:27:52.780 | it's probably better to vomit up things

01:27:55.540 | that aren't good for you rather than to pass through,

01:27:57.660 | have them pass through your system,

01:27:58.860 | especially if those things are contained in lipids.

01:28:02.580 | For instance, if you ingest something that's in lipid form

01:28:04.960 | because cells, literally every cell in your body

01:28:07.320 | is surrounded by a little thin layer of fatty tissue,

01:28:10.160 | I would call the bilayer membrane, it's a little membrane,

01:28:13.920 | fat can move through fat very easily.

01:28:16.440 | And so any bad stuff you ingest

01:28:18.580 | can get stuck in your system.

01:28:20.460 | So let's talk for a second about how to reduce nausea

01:28:23.820 | because nausea, that salivation,

01:28:25.900 | that feeling that you're going to vomit

01:28:27.780 | can be very beneficial in an adaptive circumstance,

01:28:31.540 | like you've ingested something bad,

01:28:32.780 | but some people experience nausea for other reasons.

01:28:36.100 | There are good ways to regulate nausea

01:28:39.000 | and the ways they regulate nausea are very interesting.

01:28:41.780 | They actually adjust the activity

01:28:43.900 | of these neurons and area postrema,

01:28:46.220 | or they change the chemistry of the blood directly.

01:28:49.620 | And many of you have heard this before perhaps,

01:28:52.300 | but it turns out that there are good data.

01:28:54.500 | 11 research studies were the ones that I could find,

01:28:57.020 | peer-reviewed research studies with no bias,

01:28:59.280 | so independent studies showing that ginger

01:29:02.160 | can cause a notable reduction in nausea.

01:29:06.160 | How much ginger?

01:29:07.080 | One to three grams.

01:29:08.180 | What's one to three grams?

01:29:09.100 | Well, you have to measure it out on a scale

01:29:10.340 | unless you're taking it in pill or capsule form.

01:29:12.220 | It doesn't seem to matter if you take it

01:29:13.420 | in pill or capsule form.

01:29:14.780 | So this thing that you've heard before

01:29:16.780 | that ginger can reduce nausea indeed is true.

01:29:20.260 | Peppermint apparently can also do that.

01:29:23.500 | And some of you will not be surprised to learn

01:29:26.340 | that cannabis can reduce nausea.

01:29:29.000 | Not surprised because cannabis,

01:29:30.580 | which has different legality in different places,

01:29:32.820 | and I understand that,

01:29:33.660 | so please take that into consideration,

01:29:35.160 | but cannabis, THC, and/or it turns out CBD,

01:29:40.160 | can reduce nausea.

01:29:41.420 | That's been shown in at least one study

01:29:44.020 | and it probably does that not by changing

01:29:47.100 | the chemistry of your blood,

01:29:48.140 | but by changing the threshold for firing

01:29:51.460 | of these neurons in areopostrema.

01:29:53.340 | And there are conditions such as in chemotherapy,

01:29:56.300 | radiation therapy, and others,

01:29:58.020 | where people are feeling very nauseous.

01:30:00.420 | I'm not recommending people go use cannabis

01:30:02.100 | unless they've decided with their selves

01:30:05.460 | and their family and their doctor that they should.

01:30:07.460 | But what's interesting is this thing about CBD,

01:30:09.300 | and we'll do a whole episode on THC and CBD.

01:30:11.460 | CBD doesn't have, or isn't supposed to have,

01:30:13.680 | these psychoactive properties that THC does,

01:30:16.140 | although CBD can have a mild to major anxiolytic,

01:30:19.860 | anxiety reducing effect.

01:30:21.460 | But it does appear that the data are what,

01:30:24.980 | the data support, I should say,

01:30:27.020 | the anecdotal reports,

01:30:29.620 | which are that cannabis can reduce nausea.

01:30:33.420 | So to barf less, ginger, peppermint,

01:30:36.480 | and if appropriate and legal for you, possibly cannabis.

01:30:40.000 | Now let's talk about fever.

01:30:42.180 | In previous episodes and in future episodes,

01:30:45.520 | we deal with thermal regulation,

01:30:47.380 | which is the body's ability to regulate its temperature.

01:30:50.860 | Talk about cold and heat and saunas and ice baths

01:30:53.720 | and physical performance.

01:30:55.340 | We're not going to deal with all that right now,

01:30:58.360 | but I promise we will going forward.

01:31:00.020 | Today, I only want to talk about fever

01:31:02.620 | because fever directly relates to interoception.

01:31:06.340 | What do I mean by that?

01:31:08.100 | Well, a fever is simply an increase in body temperature.

01:31:12.180 | That increase in body temperature is triggered by neurons

01:31:14.700 | in the brain.

01:31:16.260 | And those neurons in the brain are triggered by the presence

01:31:19.220 | of particular things in the bloodstream.

01:31:21.180 | What sorts of things?

01:31:24.060 | Well, toxins, bacteria, viruses.

01:31:28.200 | When something bad gets in our system,

01:31:30.640 | the body doesn't know it's bad.

01:31:33.220 | It just knows it's foreign and it hasn't seen it before

01:31:36.500 | or that it's in the wrong compartment of the body.

01:31:39.140 | So earlier we were talking about proteins

01:31:40.580 | that leak out of the gut and get elsewhere.

01:31:42.780 | You know, you don't want a piece of steak sitting

01:31:44.580 | in your bicep, that would be bad.

01:31:45.820 | You would actually develop antibodies.

01:31:47.100 | You would have a horrible infection,

01:31:48.980 | but your body has this intelligence.

01:31:51.600 | And that intelligence is to know,

01:31:53.260 | hmm, these proteins are normally not seen in this region.

01:31:56.540 | And then your body or the cells there, I should say,

01:31:59.040 | will release something that then will travel to the brain

01:32:02.820 | and will trigger an increase in body temperature

01:32:05.420 | so that your body cooks the bad thing

01:32:07.780 | or the cause of the bad thing.

01:32:09.060 | It's really a beautiful adaptive mechanism.

01:32:11.080 | We always think fever is so terrible,

01:32:12.500 | but fever is there to cook the bad thing that's inside you

01:32:16.240 | or that has left the correct compartment inside you

01:32:18.840 | and is in the wrong compartment inside you.

01:32:22.700 | So what's beautiful about the fever mechanism

01:32:26.380 | is that it looks a lot like the barfing mechanism.

01:32:28.940 | Basically, you have a set of neurons

01:32:31.280 | that sit near the ventricles.

01:32:32.980 | Remember, the ventricle is this hole in the tube that is you,

01:32:36.820 | the tube that is you.

01:32:38.080 | You are a tube, a series of tubes,

01:32:40.060 | and your brain has a hole down the middle,

01:32:42.200 | and it extends down to the bottom of your spinal cord.

01:32:44.560 | At the front, it's called the ventricles.

01:32:46.760 | They start with what are called the lateral ventricles

01:32:48.600 | and the, excuse me,

01:32:49.780 | starts with the third in the lateral ventricles,

01:32:52.220 | and then it goes to the fourth ventricle

01:32:53.660 | and then to what's called the central canal.

01:32:54.980 | But basically, it's just a big space

01:32:56.580 | in the middle of your nervous system,

01:32:58.000 | the middle of your brain.

01:32:58.900 | And you have one ventricle that I already mentioned

01:33:01.100 | called the third ventricle,

01:33:02.460 | and it's shaped kind of like a thin oval upright.

01:33:06.580 | If you're listening to this, just think an eye,

01:33:09.060 | just think the shape of an eye,

01:33:10.140 | but it's kind of rotated 90 degrees,

01:33:12.920 | so it's up and down as opposed to across.

01:33:15.900 | And along that third ventricle,

01:33:19.220 | there are little neurons that can sense

01:33:21.660 | what's in the cerebral spinal fluid

01:33:23.780 | that fills the ventricle.

01:33:24.700 | So in other words,

01:33:25.580 | you have neurons that are sensing the chemistry

01:33:27.980 | of your cerebral spinal fluid

01:33:30.500 | and that have access, therefore,

01:33:33.360 | to the chemistry of your body,

01:33:35.880 | because that cerebral spinal fluid

01:33:37.820 | is going up and down the brain and spinal cord,

01:33:39.980 | but into that cerebral spinal fluid

01:33:42.540 | are signals about the various chemicals within the body.

01:33:44.820 | So this is not a mechanical system,

01:33:46.900 | this is a chemical system.

01:33:48.620 | Remember, we're talking about mechanical information

01:33:50.620 | and chemical information accessing the brain.

01:33:53.540 | So if you have something bad in your system,

01:33:57.400 | you've ingested a virus,

01:33:58.380 | you breathed in a virus,

01:34:00.160 | or you inhaled some bacteria,

01:34:01.840 | or you got a cut on your leg

01:34:03.600 | and some bacteria are growing there,

01:34:05.600 | of course, locally, there will be effects.

01:34:09.400 | Little things called mast cells, M-A-S-T,

01:34:12.580 | little packets of histamine, literally,

01:34:14.440 | will go there and explode and cause inflammation,

01:34:17.900 | which is actually a good inflammation,

01:34:19.460 | and will release little things called macrophages

01:34:21.620 | to try to gobble up the infection.

01:34:23.720 | The other day, I was in Texas,

01:34:25.200 | there was a mean little mosquitoes in Texas

01:34:26.960 | and a lot of them,

01:34:27.980 | and I would stand outside and I'd get bitten,

01:34:29.920 | I didn't feel a thing,

01:34:30.760 | but then later that night,

01:34:32.020 | they started swelling up and itching,

01:34:34.560 | and then I'd itch them and then they'd swell even more.

01:34:36.760 | That was because of the release of mast cells,

01:34:39.380 | of histamines inside those mast cells

01:34:41.700 | that were literally causing inflammation of the tissue.

01:34:43.700 | It wasn't the poison from the mosquito itself,

01:34:45.900 | it was the immune response to those.

01:34:48.380 | Well, you also have this systemic

01:34:51.640 | or body-wide attempt to kill stuff,

01:34:54.600 | and that's the fever.

01:34:55.960 | So the neurons that line these ventricles

01:34:58.180 | with cerebral spinal fluid

01:34:59.480 | go by a particular name.

01:35:01.220 | They're called circumventricular organs,

01:35:03.660 | meaning near, circumventricular, near the ventricles,

01:35:07.460 | and you have these organs,

01:35:08.500 | and there is a set of neurons,

01:35:10.100 | has a really cool name called the OVLT.

01:35:12.420 | I don't know why I like that, but I just like it.

01:35:13.740 | It's the organum vasculosum of the lateral terminalis.

01:35:17.920 | Organum vasculosum lateral terminalis, OVLT,

01:35:21.780 | are the neurons that respond to toxins

01:35:25.380 | and bad stuff in your bloodstream,

01:35:27.220 | however minor or major,

01:35:28.940 | and they release things like ILK-1,

01:35:32.840 | which are inflammatory cytokines.

01:35:34.960 | Inflammatory, in this case, is good.

01:35:36.840 | You want inflammation at the site of an infection.

01:35:39.840 | It's a good thing.

01:35:41.300 | It's going to help with healing,

01:35:43.180 | and it's going to change the conditions in your body.

01:35:46.240 | What's going to happen is

01:35:47.680 | when those OVLT neurons are activated

01:35:49.860 | because you have something bad in your body

01:35:51.500 | or something bad is happening in your body,

01:35:54.700 | they communicate with an area of the brain

01:35:56.220 | called the preoptic area of your hypothalamus

01:35:58.780 | and the preoptic area cranks up your temperature

01:36:01.420 | and tries to cook that bad thing.

01:36:03.160 | Now, it's worth talking about fever for a moment

01:36:07.420 | and talking about thermal regulation

01:36:08.900 | because I think this actually could save some lives.

01:36:12.160 | So if you are overheated to a point

01:36:16.940 | where you're getting up past 102 or 103,

01:36:19.520 | it's going to vary depending on person to person

01:36:21.540 | and certainly age.

01:36:22.980 | Kids, some people think,

01:36:24.900 | can tolerate higher levels of fever than adults,

01:36:26.940 | but look, you always want to be cautious

01:36:28.660 | about heating up the brain too much

01:36:30.060 | because once those neurons are gone, they do not come back

01:36:32.380 | and neurons do not do well in very high temperatures.

01:36:35.340 | Once your body temperature starts getting up to 102, 103,

01:36:39.900 | certainly 104,

01:36:41.080 | you are starting to enter serious danger zone.

01:36:43.460 | This can happen through exercise in hot environments

01:36:46.540 | or an inability to escape heat

01:36:49.220 | because you don't have covering

01:36:50.460 | or adequate ventilation or cooling.

01:36:53.520 | It can also be because of excessive fever

01:36:55.620 | for whatever reason.

01:36:56.940 | A lot of people think the way to deal with this

01:36:59.100 | is to put a cool compress on the back of the neck

01:37:01.920 | or to cool the torso.

01:37:04.300 | In discussing this with my colleague, Craig Heller,

01:37:08.140 | who's at Stanford School of Medicine

01:37:11.180 | and he's on the undergraduate side of the campus as well,

01:37:13.740 | runs a biology lab.

01:37:14.820 | He's a world expert in thermal regulation.

01:37:17.320 | It's very clear that that's the wrong response

01:37:20.220 | to try and cool off the body.

01:37:22.820 | If you put a cold towel or you put an ice pack

01:37:26.740 | on the back of the neck,

01:37:27.580 | what you effectively do is cool the blood

01:37:29.700 | that's going to the brain.

01:37:31.220 | And if you do that, then your brain will react

01:37:34.780 | by turning up the crank in, so to speak,

01:37:38.420 | on the neurons in the preoptic area

01:37:40.500 | and will heat you up further

01:37:41.820 | and can cook your brain and organs further.

01:37:44.700 | So what you want to do is, as I've talked about before,

01:37:47.220 | you want to cool the bottoms of the feet,

01:37:50.500 | the palms of the hands, and the upper part of the face.

01:37:53.620 | And I'm not going to go into all the details

01:37:55.440 | as to why you want to do that right now,

01:37:57.100 | but those are the locations you want to cool.

01:37:58.780 | Now, you can also cool the rest of the body,

01:38:00.860 | but it's not okay to just stay under the covers

01:38:03.260 | and just cool the neck or something like that.

01:38:06.340 | You really want to try and create a systemic

01:38:09.180 | or whole body cooling if the goal is to bring fever down.

01:38:12.120 | But in many cases, fever is adaptive.

01:38:14.060 | And so taking non-steroid and inflammatory drugs

01:38:17.680 | like Advil and Tylenol sometimes can be good

01:38:21.720 | if that's recommended, but other times,

01:38:23.280 | because it reduces your fever, it's allowing that pathogen,

01:38:26.940 | that pyrogen, it's sometimes called.

01:38:28.680 | A pyrogen is a substance that causes fever.

01:38:30.920 | Think pyro, think fire, think pyromaniacs, think pyro.

01:38:35.520 | Those pyrogens can survive at moderate to low temperatures,

01:38:40.400 | and they can't survive at high temperatures.

01:38:41.840 | So the fever is an adaptive mechanism,

01:38:43.840 | and the OVLT and the sensing of your chemistry

01:38:46.700 | is how the OVLT, organum vasculosum

01:38:49.340 | and the lateral terminalis does that.

01:38:51.580 | So we've talked about sensing lung volume,

01:38:55.220 | speed of our heartbeat.

01:38:56.320 | We talked about sensing the gut volume,

01:38:59.200 | the intestinal volume, or the absence of volume.

01:39:01.520 | We talked about chemistry of the gut and the gut microbiota

01:39:06.520 | and autoimmune functions.

01:39:08.360 | And we've now talked about vomiting,

01:39:11.040 | and we've talked about fever.

01:39:13.120 | Lots of aspects of sensing our internal self.

01:39:16.120 | Now I want to turn our attention to interoception

01:39:19.540 | as it relates to feelings,

01:39:22.240 | the way that interoception is most commonly described.

01:39:25.320 | And I want to highlight a term

01:39:27.020 | that many of you have probably heard,

01:39:28.260 | which is the vagus nerve.

01:39:29.800 | We talked about vagus a little bit earlier,

01:39:31.480 | but the vagus nerve, this vagabonding, wandering nerve

01:39:35.760 | is involved in everything I've talked about up until now.

01:39:39.620 | And the reason I saved it till now,

01:39:41.720 | rather than mentioning it all along,

01:39:43.120 | is to highlight a specific point,

01:39:45.180 | which is that whenever we hear about the vagus

01:39:47.460 | in popular culture, it's like the vagus calms you down.

01:39:50.020 | You want to stimulate the vagus

01:39:51.160 | by rubbing in front of the ear,

01:39:52.560 | and it's a parasympathetic nerve,

01:39:53.940 | and it will calm you down, it'll mellow you out.

01:39:55.660 | Actually, most of the time, the vagus is stimulatory.

01:39:59.700 | When you ingest foods with amino acids,

01:40:02.060 | sugars, or fatty acids,

01:40:04.260 | the vagus nerve gets activated

01:40:07.340 | and triggers the release of dopamine.

01:40:08.820 | It makes you more alert and go seek more of those foods

01:40:12.080 | or what led to those conditions.

01:40:14.820 | When you feel nauseous, it's rarely calming.

01:40:17.220 | When you feel like you have a fever, it's rarely calming.

01:40:20.100 | So you're starting to get the picture

01:40:21.380 | that even though the vagus nerve

01:40:23.940 | is in the parasympathetic branch

01:40:26.200 | of the autonomic nervous system,

01:40:27.500 | and if that doesn't mean anything to you

01:40:28.720 | 'cause you're not an aficionado, don't worry about it,

01:40:30.960 | but it's not a calming system.

01:40:33.240 | It's a communication system, and it's a motor system.

01:40:36.500 | It communicates brain to body and body to brain,

01:40:38.800 | and it changes the function of different organs.

01:40:41.440 | Now, one thing that's important to highlight

01:40:45.160 | is that stress itself will alter the chemistry of your gut

01:40:50.160 | because of the ways that it shuts down the vagus nerve

01:40:54.840 | and quiets the neurons that communicate from gut to brain.

01:40:58.140 | I want to say that again.

01:40:59.260 | Stress will disrupt your gut and make you feel not good,

01:41:03.200 | poor digestion and just lousy,

01:41:05.840 | because of the way that it shuts down the vagus nerve

01:41:09.120 | and the neurons of your gut.

01:41:10.700 | So what stress does is it blocks the communication

01:41:13.900 | between gut and brain.

01:41:15.340 | It doesn't mess up your gut.

01:41:16.740 | It just doesn't let your gut get the signals

01:41:18.740 | up to your brain, and it also then throws off the chemistry,

01:41:22.420 | and then there's a whole cascade of effects.

01:41:24.180 | If you want to learn more about stress,

01:41:25.460 | I did a whole episode called Master Stress,

01:41:27.820 | or I think maybe it was called Conquer Stress.

01:41:29.160 | I think it was Master Stress, either one.

01:41:31.300 | The whole point of that episode

01:41:32.480 | is to give you tools and practices

01:41:33.840 | to deal with short-term acute stress, moderate-term stress,

01:41:37.260 | and long-term chronic stress through behavioral mechanisms,

01:41:40.820 | nutrition, supplementation, and many other things as well.

01:41:45.100 | It's chock-a-block full of protocols and tools for stress.

01:41:48.060 | The vagus nerve, however, is responsible for emotion,

01:41:53.900 | and the way it does that is to pool,

01:41:57.020 | to aggregate the conditions of your gut,

01:42:00.420 | the conditions of your heart

01:42:01.980 | and the conditions of your breathing,

01:42:03.900 | which includes your diaphragm and lungs,

01:42:05.940 | and takes that kind of as a collection of information

01:42:10.820 | and sends it to the brain

01:42:12.420 | and controls what we call your emotions.

01:42:14.860 | Now, that might seem obvious to some people,

01:42:19.040 | but to other people, that might seem totally crazy.

01:42:21.560 | You thought your emotions were

01:42:22.940 | because the market was down and you had invested,

01:42:25.700 | or because something that you thought was going to happen

01:42:28.180 | is not going to happen,

01:42:29.920 | or because you thought that school was going to open

01:42:33.140 | and then it's not,

01:42:34.140 | or maybe you thought it wasn't and it is.

01:42:36.200 | Whatever it is that bothers you,

01:42:37.760 | you think of generally as a purely cognitive event,

01:42:41.300 | but the brain doesn't really know

01:42:43.900 | what to do with that information.

01:42:45.740 | It doesn't act directly on that information to create moods.

01:42:48.900 | Moods are created through the heart's response

01:42:52.400 | to reading that headline,

01:42:54.380 | to the change in your breathing

01:42:55.820 | that's caused by someone that you love telling you

01:42:58.820 | that actually they're not interested

01:43:00.460 | in spending time with you anymore,

01:43:01.700 | or that you screwed up,

01:43:02.620 | or that they're interested in spending

01:43:04.100 | a lot of time with you and you like that, right?

01:43:06.720 | Emotions can be good or bad or neutral.

01:43:09.460 | So this thing that we call interoception, the sense of self,

01:43:13.580 | I've been building up from very fundamental layers,

01:43:16.260 | gut chemistry, spleens, immune systems, autoimmune,

01:43:20.340 | and you might've been thinking,

01:43:21.500 | wait, I thought this was going to be about a sense of self,

01:43:24.180 | a noticing or a feeling.

01:43:26.500 | And indeed, all of those things are plugging in

01:43:29.540 | like a series of ingredients in a recipe

01:43:32.100 | that gives rise to your mood and how you feel.

01:43:35.300 | And that mood and how you feel

01:43:37.540 | is shown in one location in your body

01:43:41.780 | that other people can see,

01:43:43.340 | and that's in your facial expressions.

01:43:45.780 | And indeed, there are now beautiful data

01:43:48.300 | showing that your face,

01:43:51.620 | including the size of your pupils,

01:43:53.900 | the tonality of your face,

01:43:55.280 | how flushed you are or how pale you are,

01:43:59.100 | even the degree to which you are frowning or smiling

01:44:02.540 | relative to other periods of time,

01:44:05.260 | that is all an aggregate of, or a reflection rather,

01:44:10.260 | of your gut, your heart, and your breathing,

01:44:12.700 | and the chemistry of your body.

01:44:14.460 | And so this is why I sort of backed into this conversation

01:44:17.360 | about interoception.

01:44:18.260 | I kind of Trojan horse this on you on purpose,

01:44:21.800 | which is that when we talk about the vagus and you hear,

01:44:24.340 | oh, you know, you can get vagal tone by breathing

01:44:26.740 | or rubbing on the front of the ear.

01:44:27.740 | Sure, that's probably true.

01:44:29.480 | But another fundamental layer is the acidity of your gut,

01:44:33.860 | how fast you're breathing.

01:44:35.060 | Are you inhale-emphasized or exhale-emphasized breathing?

01:44:40.020 | When we are relaxed, our pupils tend to constrict.

01:44:44.740 | When we are very alert, our pupils tend to be dilated,

01:44:49.100 | whether or not that alertness

01:44:50.140 | has to do with being happy or being sad.

01:44:53.620 | And what's remarkable, and this is where interoception

01:44:56.180 | really, really takes a leap into the incredible,

01:44:59.980 | is that there are beautiful studies that show

01:45:02.820 | that, for instance, when we know somebody pretty well

01:45:06.100 | and they are going through some sort of experience

01:45:08.740 | of any kind, our heart rate actually starts

01:45:12.220 | to mimic their heart rate.

01:45:14.180 | Our breathing starts to mimic their breathing,

01:45:16.180 | even if we aren't conscious of their breathing.

01:45:18.740 | It's not like we see their chest heaving

01:45:20.740 | and we think, oh my goodness, and then we breathe that way.

01:45:25.580 | There's a mirroring.

01:45:27.020 | And no, it's not carried out through mirror neurons.

01:45:28.980 | Mirror neurons are more of a myth than a reality.

01:45:31.120 | Sorry to burst people's bubbles,

01:45:32.860 | but that bubble around mirror neurons

01:45:34.620 | is definitely made of myths and a topic for another time.

01:45:38.940 | But we start to mirror.

01:45:41.020 | Somehow, human beings are able to register

01:45:44.220 | the internal state of other beings,

01:45:46.300 | and I think probably for animals too,

01:45:47.780 | but certainly for other humans, even at a distance.

01:45:51.020 | And these studies are many now,

01:45:52.900 | and they're really wonderful studies.

01:45:54.540 | And so your sense of your internal landscape

01:45:58.240 | is linked to others.

01:46:00.300 | Now you can enhance this interoceptive capacity

01:46:03.660 | for how you feel and how others feel.

01:46:05.660 | In other words, you can start getting a better readout

01:46:08.960 | of your internal state by doing a simple exercise,

01:46:13.460 | what is really a tool,

01:46:15.940 | and that is to learn to sense your heartbeats.

01:46:19.540 | So some people are very good at this.

01:46:21.860 | Other people are not.

01:46:23.300 | Some people can do this more easily

01:46:24.900 | when they have all their air exhaled,

01:46:26.740 | and some people can do it better

01:46:27.860 | when they are holding a breath hold.

01:46:30.580 | But one thing that's kind of cool

01:46:32.980 | about this whole interoceptive capacity

01:46:36.000 | is that you can enhance it very, very quickly.

01:46:38.460 | You can learn or teach yourself

01:46:40.460 | to have heightened levels of interoception

01:46:42.660 | in a way that you can't really just give yourself

01:46:45.720 | heightened levels of vision by snapping your fingers

01:46:47.920 | in one round of one tool or exercise.

01:46:50.180 | There are things you can do to improve vision.

01:46:51.800 | That's the topic of a previous episode.

01:46:53.360 | I encourage you to look it up.

01:46:54.400 | There are things you can do to improve your hearing

01:46:56.680 | and your taste and your smell.

01:46:58.160 | We talked about all those.

01:46:59.780 | But within interoception,

01:47:01.120 | you can get very good at this very fast,

01:47:03.500 | and I think this is one of the reasons

01:47:04.600 | why meditation is powerful.

01:47:06.360 | I think there are a lot of reasons

01:47:07.280 | why meditation is powerful,

01:47:08.320 | but one of the reasons is when you stop

01:47:10.200 | taking in exteroceptive information,

01:47:12.660 | information from the outside world,

01:47:14.660 | by closing your eyes and focusing inward, as they say,

01:47:17.680 | you start paying attention to your breathing cadence.

01:47:20.880 | You start directing your mind's attention

01:47:23.380 | to your heart rate.

01:47:24.980 | And if you can start to perceive your heart beating,

01:47:28.240 | you actually are very quickly strengthen

01:47:31.800 | the vagal connections between the body and the brain.

01:47:35.120 | And so there's no real practice here.

01:47:36.900 | There's no breathe this way or do this thing,

01:47:39.600 | except to direct your awareness toward your heartbeat.

01:47:44.600 | And some people can get very good at this very fast.

01:47:48.520 | Most people find that just by doing this

01:47:50.140 | for a minute or so every once in a while,

01:47:52.840 | they start to tap into this sixth sense.

01:47:55.540 | They start to notice when they don't feel quite right

01:47:59.600 | about something or somebody or some situation,

01:48:02.480 | or they start to notice when they feel quite right

01:48:05.680 | about somebody or something or some situation.

01:48:08.200 | So this interoceptive awareness can be tuned up.

01:48:10.920 | It used to be called vagal tone,

01:48:13.120 | but I think that term doesn't take into account

01:48:15.200 | all the other things that are going on with the vagus.

01:48:17.360 | So I don't really like that term.

01:48:18.760 | It's more of an interoceptive awareness.

01:48:21.840 | And again, there are many studies now showing

01:48:25.020 | that for sake of bettering one's mood overall,

01:48:29.140 | for sake of moving through a challenging phase in life,

01:48:31.700 | for sake of just enhancing one's experience of life overall,

01:48:35.400 | whether or not it's the taste of foods,

01:48:36.720 | interactions with other people, enjoyment, focus, pleasure,

01:48:41.640 | tuning up one's interoceptive awareness is both easy,

01:48:45.240 | again, by just taking a minute or two

01:48:46.980 | and trying to count heartbeats.

01:48:49.200 | And then this works best, of course,

01:48:50.860 | if you have some independent readout of heartbeats

01:48:52.900 | and you can compare, you can see how accurate you are.

01:48:55.960 | But even if you don't use a device

01:48:57.760 | or have a device to do that, without taking your pulse,

01:49:01.200 | using your thumb on your wrist or something

01:49:02.760 | or your fingers on your neck,

01:49:04.140 | as you typically would for taking your pulse,

01:49:06.160 | trying to sit still for a minute or two,

01:49:09.280 | every once in a while, maybe once a week,

01:49:11.280 | maybe twice a week, maybe while you're meditating,

01:49:13.700 | maybe while breath work,

01:49:14.680 | maybe during the breath holds of breath work,

01:49:16.100 | you don't really have to do this in any kind of extended way.

01:49:19.020 | You can very quickly increase your interoceptive tone.

01:49:21.960 | And that has a huge and outsized effect

01:49:25.140 | on the brain-body relationship

01:49:28.160 | and your brain's ability to tap into both the subconscious

01:49:33.160 | and the conscious aspects of this chemical

01:49:36.180 | and mechanical signaling that's happening all the time.

01:49:38.400 | And it can have real and outsized positive effects

01:49:41.200 | on your ability to engage with other people

01:49:43.440 | and your ability to focus at work.

01:49:45.880 | And your ability to notice,

01:49:47.360 | ah, I'm finding myself kind of feeling

01:49:51.000 | like I'm losing focus,

01:49:52.300 | but really it was my heart rate was just increasing.

01:49:54.220 | Maybe I just exhale a little bit

01:49:55.640 | and bring my heart rate down.

01:49:57.980 | So what I've effectively tried to do today

01:50:00.060 | is to give you a window into this incredible relationship

01:50:03.840 | between your viscera and your brain

01:50:05.800 | and your brain and your viscera,

01:50:06.960 | all these organs of your body.

01:50:08.120 | And what I hope is that you'll appreciate that it's a system

01:50:12.480 | that you aren't just a system of tubes.

01:50:14.660 | I said that in sort of ingest.

01:50:16.120 | I mean, you have a lot of tubes

01:50:17.060 | and you are a system of tubes,

01:50:18.360 | but that system of tubes is linked

01:50:20.500 | through the nervous system.

01:50:22.140 | And those links work in very specific ways.

01:50:25.000 | So whether or not you remember about piezos

01:50:27.060 | and all the GLP-1Rs and all that stuff,

01:50:28.920 | it doesn't really matter.

01:50:30.240 | What I encourage you to do is start sort of pushing

01:50:33.400 | and pulling on the various levers

01:50:34.940 | within this beautiful system

01:50:36.260 | that we call the interoceptive system, this sense of self.

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01:51:13.980 | During the course of today's episode

01:51:15.480 | and on previous episodes, I mentioned supplements.

01:51:18.000 | I realize supplements aren't for everybody,

01:51:19.800 | but for those of you that are interested in supplements,

01:51:22.080 | it is important that the supplements that you take

01:51:24.380 | have a high level of stringency

01:51:26.380 | with respect to the amounts of the contents

01:51:28.680 | that are listed on the bottle,

01:51:29.660 | matching what's actually in the bottle,

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01:51:43.840 | and the amount of content in those bottles and supplements.

01:51:47.200 | If you want to try Thorne supplements

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01:52:39.080 | (upbeat music)

01:52:41.660 | (upbeat music)

How to Optimize Your Brain-Body Function & Health | Huberman Lab Podcast #30

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