How to Prevent & Treat Colds & Flu

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

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

00:00:04.920 | for everyday life.

00:00:05.940 | I'm Andrew Huberman,

00:00:10.400 | and I'm a professor of neurobiology and ophthalmology

00:00:13.560 | at Stanford School of Medicine.

00:00:15.500 | Today, we are discussing colds and flus.

00:00:18.200 | We will talk about what a cold really is

00:00:20.480 | and what a flu really is

00:00:21.820 | in terms of how they impact your brain and body.

00:00:24.000 | And of course, we will discuss

00:00:25.280 | how to avoid getting colds and flus.

00:00:27.320 | There are indeed some excellent science-supported techniques

00:00:30.960 | to avoid getting colds and flus,

00:00:32.880 | but of course, it is impossible to completely avoid

00:00:36.460 | ever getting a cold or flu in your lifetime.

00:00:39.000 | So we also discuss how to more quickly

00:00:41.040 | get over a cold or flu should you happen to catch one.

00:00:44.820 | So during today's discussion,

00:00:46.000 | I'll talk about the immune system.

00:00:47.460 | I'll give you some mechanistic understanding

00:00:49.080 | of how your immune system works,

00:00:50.840 | and I promise to make that discussion

00:00:52.400 | accessible to everybody,

00:00:54.100 | regardless of whether or not you have a background

00:00:55.640 | in biology.

00:00:56.520 | And with that understanding of how your immune system works,

00:00:59.360 | you will be in a much better position

00:01:01.360 | to understand which tools,

00:01:03.180 | that is which protocols to implement,

00:01:05.440 | should you be exposed to a cold or flu,

00:01:07.720 | or if you are trying to get over a cold or flu

00:01:10.320 | more quickly than you would otherwise.

00:01:12.720 | You'll learn about some potent behavioral tools

00:01:15.080 | for bolstering your immune system.

00:01:16.840 | And we will also discuss various compounds

00:01:19.320 | that you might consider taking

00:01:20.820 | to enhance the function of your immune system

00:01:22.920 | to ward off or treat colds and flus.

00:01:25.240 | I will also be dispelling a number of common myths

00:01:28.360 | about treatments for the common cold and for the flu.

00:01:31.600 | There are oh so many ideas out there

00:01:33.240 | about what one could take or do

00:01:35.540 | in order to avoid getting the cold or flu

00:01:37.800 | or more quickly get relief from a cold or flu.

00:01:41.340 | However, many of those are pure myth.

00:01:44.080 | There's just no science to support them.

00:01:45.700 | And indeed there's some science that counters those ideas.

00:01:49.040 | But the good news is there are indeed

00:01:51.240 | science supported behavioral protocols

00:01:53.040 | and compounds that one could consider

00:01:55.160 | in order to avoid and treat colds and flus.

00:01:58.440 | Before we begin, I'd like to emphasize that this podcast

00:02:01.080 | is separate from my teaching and research roles at Stanford.

00:02:03.880 | It is however, part of my desire and effort

00:02:06.280 | to bring zero cost to consumer information about science

00:02:08.840 | and science related tools to the general public.

00:02:11.440 | In keeping with that theme,

00:02:12.480 | I'd like to thank the sponsors of today's podcast.

00:02:15.320 | Our first sponsor is Juve.

00:02:17.200 | Juve makes medical grade red light therapy devices.

00:02:20.700 | Now, if there's one thing I've consistently emphasized

00:02:22.840 | on this podcast is the incredible role that light can have

00:02:26.280 | on our biology.

00:02:27.480 | And of course, I'm always telling people

00:02:29.000 | that they should get sunlight in their eyes

00:02:30.560 | as soon as possible after waking

00:02:32.040 | on as many days of their life as possible

00:02:34.500 | for sake of setting circadian rhythm, daytime mood focus

00:02:36.840 | and alertness and improve sleep.

00:02:39.140 | Now, in addition to sunlight,

00:02:40.920 | red light and near infrared light has been shown

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00:02:47.500 | including faster muscle recovery, improved skin health

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00:06:00.520 | Okay, let's talk about the common cold.

00:06:03.060 | First off, no, unfortunately today,

00:06:05.800 | I cannot tell you the cure for the common cold

00:06:08.340 | because indeed there isn't one.

00:06:11.260 | One interesting question, however,

00:06:12.620 | is why don't we have a cure for the common cold?

00:06:15.360 | And the reason is that the cold virus, as it's referred to,

00:06:19.020 | is actually a bunch of different viruses.

00:06:21.780 | Some colds are caused by one,

00:06:23.800 | what's called serotype of the virus.

00:06:25.900 | Other colds are caused by a different serotype of the virus.

00:06:29.820 | There are over 160 different types

00:06:32.880 | of what people call the cold virus.

00:06:35.380 | Now, cold viruses fall under an umbrella

00:06:37.440 | of a general category of viruses called rhinoviruses.

00:06:40.520 | You can remember that easily

00:06:41.680 | because rhino sounds like rhino's horn,

00:06:44.000 | the rhinoceros horn,

00:06:45.000 | which is of course in the center of the rhino's face,

00:06:47.960 | which is where your nose is.

00:06:49.080 | And the cold almost always causes some degree

00:06:52.440 | of nasal symptoms in humans.

00:06:54.300 | It's either runny nose or sneezing or stuffed up nose,

00:06:57.040 | or sometimes unfortunately all three.

00:06:59.740 | Now, the reason we don't have a cure for the common cold

00:07:01.640 | is that all of those different serotypes of the cold virus

00:07:05.000 | mean that the virus itself has a different shape

00:07:07.360 | on its outside.

00:07:08.300 | And as a consequence, even if you've been exposed to a cold

00:07:11.680 | and you've developed antibodies against that cold virus,

00:07:14.820 | the next cold that comes along

00:07:16.320 | very likely has a different shape,

00:07:18.620 | and therefore your body's antibodies

00:07:20.940 | to the cold virus it combated successfully before

00:07:23.940 | can't latch onto and defeat

00:07:25.860 | that next different serotype of the cold virus.

00:07:29.000 | Now, a little bit later,

00:07:29.840 | I'll talk about the immune system

00:07:31.060 | and how those different antibodies are generated.

00:07:33.740 | But for the time being,

00:07:35.180 | understanding that there are a lot of different types

00:07:37.020 | of cold viruses explains, first of all,

00:07:39.380 | why we don't have a cure for the common cold,

00:07:41.700 | but also why you can get multiple colds

00:07:43.860 | within a given year or even within a given season.

00:07:46.420 | Because even if you develop antibodies

00:07:48.100 | against one serotype of the cold virus,

00:07:50.420 | a different serotype can come along

00:07:51.900 | and you can get sick again

00:07:53.220 | with that new serotype of the cold virus.

00:07:55.700 | So how do you catch a cold?

00:07:57.220 | Now, one of the problems with the cold virus

00:07:59.180 | being called the cold virus,

00:08:01.140 | and the fact that indeed there are more cold viruses present

00:08:05.380 | and transmitted between humans

00:08:07.100 | in the cold winter months of the year,

00:08:10.220 | is that people generally assume

00:08:11.960 | that it is the cold temperatures outside

00:08:14.100 | that actually give you a cold virus.

00:08:16.820 | And that is simply not true.

00:08:18.580 | However, what you heard as a kid,

00:08:20.320 | if your mom most likely, but maybe your dad said,

00:08:23.020 | "Hey, don't go outside without a sweater or jacket on,

00:08:25.380 | you're going to catch a cold,

00:08:26.980 | or you're going to catch cold,"

00:08:28.780 | has propagated this myth

00:08:31.320 | that the cold temperatures themselves

00:08:33.740 | are the cause of catching a cold virus.

00:08:35.940 | And that's simply not true.

00:08:37.500 | The virus that we call the cold virus

00:08:40.380 | is spread by breathing, or by sneezing,

00:08:44.620 | or by people sneezing or coughing

00:08:46.900 | or breathing onto their hands,

00:08:48.780 | and then touching surfaces,

00:08:50.740 | and then other people touching those surfaces,

00:08:53.100 | and then touching most likely their eyes

00:08:56.020 | in order to self-infect.

00:08:57.900 | Now, we're going to get into the details

00:08:59.380 | of how far the virus can spread with a sneeze,

00:09:02.660 | how long it can survive on the hands, et cetera.

00:09:05.680 | But for the time being, know this,

00:09:07.620 | the cold virus is a pretty stable virus

00:09:10.480 | in that it can survive on surfaces,

00:09:13.620 | non-human or human surfaces,

00:09:15.660 | meaning skin or on a table or on a glass

00:09:18.080 | or on a door handle for up to 24 hours.

00:09:21.640 | So for all you hypochondriacs out there,

00:09:23.740 | I probably just gave you a little spike in cortisol.

00:09:26.200 | And for you non-hypochondriacs,

00:09:28.460 | I hope what I just said cues you to the fact

00:09:30.720 | that just avoiding people who are sneezing and coughing

00:09:33.780 | is not sufficient to avoid getting colds and flus.

00:09:36.340 | However, the fact that a cold virus

00:09:39.260 | is alive and well on a given surface,

00:09:41.660 | let's say on a door handle,

00:09:43.280 | does not mean that if you touch that door handle

00:09:45.340 | that you will necessarily be infected with that cold virus.

00:09:48.620 | And that's because your skin

00:09:50.040 | actually provides an excellent barrier

00:09:51.940 | against most viruses and bacteria.

00:09:54.740 | Your skin also includes a lot of antiviral substances on it.

00:09:59.080 | Even if you haven't put any of that,

00:10:00.640 | you know, alcohol stuff or the hand sanitizer stuff on,

00:10:03.580 | your skin is a very important barrier component

00:10:05.880 | of your immune system.

00:10:07.020 | We're gonna talk about that a little bit later.

00:10:09.020 | But if somebody has a cold

00:10:10.060 | and they happen to perhaps, you know, wipe their nose

00:10:12.380 | or sneeze into a tissue, hopefully into a tissue,

00:10:14.540 | and then discard that tissue,

00:10:16.020 | the cold virus particles are extremely small.

00:10:20.860 | How small?

00:10:21.700 | Well, most of us are familiar

00:10:23.200 | with thinking about centimeters or inches.

00:10:26.140 | If you think about a millimeter

00:10:27.420 | being one one hundredth of a centimeter,

00:10:30.320 | well, you can take a millimeter

00:10:31.940 | and you can divide that up

00:10:33.740 | into a bunch of little slices also,

00:10:35.800 | such that you get the micron.

00:10:37.520 | The micron is one one thousandth of a centimeter.

00:10:41.220 | And if you wanna get a sense of how thick or thin that is,

00:10:44.780 | the side of a credit card,

00:10:45.980 | the little thin side of a credit card,

00:10:48.320 | is about 200 microns thick.

00:10:50.980 | So if you set your credit card flat on a table

00:10:53.340 | and then you look at it from the side,

00:10:54.600 | that tiny, tiny, thin little edge,

00:10:55.940 | that's about 200 microns.

00:10:57.880 | The cold virus is made up of particles

00:11:00.820 | that are probably in the range of about five microns or so.

00:11:04.460 | So it's extremely small.

00:11:05.920 | I mean, the cold virus,

00:11:07.380 | therefore, with a good sneeze or even a light sneeze,

00:11:10.340 | can spread really far.

00:11:12.100 | Now, the good news is those particles are relatively heavy.

00:11:14.480 | They don't tend to mist about in the air for very long.

00:11:16.940 | They tend to fall down onto the ground or onto surfaces.

00:11:19.880 | But as I mentioned before,

00:11:20.820 | they can survive for a very long time on those surfaces.

00:11:23.820 | So should you touch your hand to a door handle

00:11:25.900 | or table or shake the hand of somebody

00:11:28.520 | that has cold virus on their hands,

00:11:30.020 | either because they themselves have a cold

00:11:31.680 | or they contacted somebody else that had cold virus

00:11:34.080 | and it somehow landed on their hands

00:11:36.040 | just 'cause the other person sneezed.

00:11:37.580 | All these scenarios are very realistic.

00:11:39.660 | That cold virus will not infect you

00:11:44.180 | unless it can get inside of your body.

00:11:46.400 | And one of the primary entry points

00:11:48.040 | of it getting inside your body is via the eyes,

00:11:51.360 | by wiping that cold virus on your eyes.

00:11:53.900 | Now you may think, okay, I'm just not gonna touch my eyes.

00:11:56.960 | But a little bit later, we're going to talk about a study

00:11:59.260 | that shows that almost always, indeed, almost always,

00:12:03.720 | when you meet somebody new, you touch your eyes.

00:12:06.780 | And the frequency of people touching their face,

00:12:10.280 | that is the region of the face around the eyes

00:12:12.320 | and their eyes throughout the day is extremely high.

00:12:15.740 | So this is one of the primary routes

00:12:18.060 | by which the cold virus is transmitted

00:12:19.640 | from one person to the next.

00:12:21.020 | But of course, there's also the route

00:12:22.740 | that we're all familiar with,

00:12:23.700 | which is the person that is sneezing or coughing

00:12:25.980 | or blowing their nose into tissues

00:12:27.440 | and then throwing them in the trash

00:12:28.700 | and not washing their hands

00:12:29.760 | after each and every time they do that.

00:12:32.220 | So an important aspect of today's discussion

00:12:33.900 | that we will get into once I also present to you

00:12:36.400 | what a flu is and how it differs from the cold,

00:12:38.900 | is that we're going to need to talk about

00:12:40.740 | what stage of infection people are actually contagious

00:12:44.600 | with the cold or flu.

00:12:45.860 | And there's actually a lot of mythology about this.

00:12:48.000 | In fact, there's a lot of just lying about this.

00:12:50.180 | People will be coughing or sneezing and they'll say,

00:12:52.580 | oh yeah, I'm not contagious any longer.

00:12:54.280 | Or people make up these things like,

00:12:56.520 | oh, you know, if you had the flu for two days,

00:12:58.760 | then you're no longer contagious.

00:13:00.020 | Or that you can't be contagious until you have symptoms.

00:13:02.820 | So we're going to go through all the aspects of contagion

00:13:05.920 | and how coughing or sneezing

00:13:07.200 | or how long you've had a cold or flu

00:13:09.300 | actually relates to whether or not

00:13:10.880 | you're contagious in a little bit.

00:13:12.140 | But for the time being,

00:13:13.180 | know that the cold virus is very, very small.

00:13:15.840 | It can be transmitted through the air.

00:13:17.900 | It can be transmitted via contact,

00:13:20.260 | from skin to skin contact,

00:13:21.460 | and it can survive on surfaces for up to 24 hours.

00:13:24.180 | And when you touch those surfaces

00:13:25.520 | or a person with the cold virus,

00:13:27.780 | most often the way it's going to get into your body

00:13:30.180 | and infect you such that you get a cold

00:13:32.640 | is by touching your eye region.

00:13:34.340 | Although touching other regions of your body

00:13:36.300 | can also pass the cold virus into you.

00:13:37.900 | For instance, the mouth and lips,

00:13:39.700 | but that's actually far less common.

00:13:41.300 | So we'll get into that in just a little bit.

00:13:43.360 | Now, different serotypes,

00:13:44.780 | that is different types of cold virus,

00:13:46.880 | tend to create a different array of overall symptoms

00:13:50.080 | such that, you know, one cold might be a really,

00:13:51.940 | quote unquote, bad cold.

00:13:53.540 | Others are more mild.

00:13:54.840 | Some tend to induce more runny nose,

00:13:57.080 | others more stuffy head and a little bit of fever,

00:13:59.440 | or in some cases, a lot of fever.

00:14:01.360 | One thing that's important to understand

00:14:02.480 | is that if people are going to be infected

00:14:04.040 | by the cold virus,

00:14:05.340 | they tend to develop symptoms one to two days

00:14:07.840 | after they were exposed to the virus.

00:14:10.040 | Now, the good news is,

00:14:11.580 | if you are exposed to the cold virus,

00:14:13.420 | that doesn't necessarily mean

00:14:15.040 | that you are going to catch that cold virus.

00:14:17.360 | That is, if your immune system can fight off that cold,

00:14:20.520 | even if you've never been exposed to that serotype before,

00:14:23.920 | then you won't actually have that cold

00:14:25.940 | and you won't transmit it.

00:14:27.220 | So put differently,

00:14:28.520 | it is possible to avoid getting a cold virus

00:14:31.740 | even if you've never been exposed

00:14:33.280 | to that serotype of cold virus,

00:14:34.760 | and you happen to come into contact with somebody

00:14:37.000 | who has that serotype of cold virus,

00:14:39.320 | or you touch a surface of some object or handle, et cetera,

00:14:43.660 | that has a particular serotype of the cold virus on it,

00:14:46.560 | and God forbid, you then wipe your eyes.

00:14:48.880 | That doesn't necessarily mean that you're going to get sick.

00:14:51.440 | And a good portion of today's episode

00:14:53.040 | is going to focus on tools that are supported by science

00:14:55.800 | that allow you to bolster your immune system

00:14:58.800 | and greatly increase the probability

00:15:00.860 | that even if you're exposed

00:15:02.400 | to a novel serotype of the cold virus,

00:15:04.200 | that is one that's new to you,

00:15:05.780 | that your body's never seen before,

00:15:07.340 | that you won't get sick.

00:15:08.720 | Another thing to understand about the cold virus

00:15:10.600 | is that you're generally most contagious to other people

00:15:13.320 | when you feel at your worst.

00:15:15.080 | That is when you're coughing and sneezing

00:15:16.600 | and you've got the stuffy head, watery eyes, and so on.

00:15:19.820 | But you can also be contagious to other people

00:15:22.200 | when you are starting to feel better.

00:15:24.720 | That said, most of the data point to the fact

00:15:26.900 | that about five to six days

00:15:28.760 | after you hit your peak of worst symptoms,

00:15:32.380 | or I guess we should say your nadir,

00:15:33.960 | the dip of worst symptoms,

00:15:35.140 | 'cause it's such an awful state to be in,

00:15:37.460 | you are probably exiting the phase in which you're contagious.

00:15:40.800 | Now, I want to be very clear,

00:15:42.240 | that does not mean that if you've had a cold

00:15:44.700 | for five or six days, that you are no longer contagious.

00:15:47.080 | If you continue to experience sneezing and coughing,

00:15:49.620 | watery eyes, in the evening, you're feeling much worse,

00:15:52.800 | first thing in the morning,

00:15:53.760 | you're feeling especially groggy, et cetera,

00:15:56.380 | well, then you are still contagious.

00:15:58.280 | Another way to frame this is, you know those people

00:16:01.040 | that continue to show up at the gym and show up at work,

00:16:03.960 | and they tell you, "Yeah, I got this cold,

00:16:06.240 | "but I've had it for a few days, I'm no longer contagious,"

00:16:09.160 | and they're wiping their eyes

00:16:10.020 | and they're blowing their nose.

00:16:11.720 | Frankly, they don't know what they're talking about.

00:16:13.260 | They are basically a walking, talking, breathing,

00:16:16.440 | sneezing, coughing, cold virus vector.

00:16:19.400 | A vector is a route for passage of a virus.

00:16:23.880 | So please, if you are sneezing, if you are coughing,

00:16:27.740 | if you are still experiencing the symptoms of a cold,

00:16:30.680 | stay home, stay away from other people as much as possible.

00:16:33.560 | And I realized that some people simply cannot avoid

00:16:35.760 | going to work or cannot avoid interacting

00:16:38.360 | with other family members or other people

00:16:40.160 | if they have the cold virus,

00:16:41.520 | but this mythology that if we've had a cold for a few days

00:16:45.180 | and we're starting to feel better,

00:16:46.380 | but we're still exhibiting symptoms

00:16:47.620 | that we're not contagious, that is pure myth.

00:16:50.480 | It's simply not grounded, in fact.

00:16:52.760 | Now, there's nothing that can be done

00:16:54.560 | about that first day or two

00:16:56.140 | after which we're exposed to a cold virus

00:16:57.860 | where we are not experiencing symptoms,

00:17:00.380 | and it's quite possible to pass the cold virus

00:17:03.060 | on to other people.

00:17:03.900 | But I think that every workplace, every home environment,

00:17:06.940 | every gym, every society would benefit greatly

00:17:10.100 | if people who were sick with the cold

00:17:12.340 | did not expose other people to that cold virus

00:17:15.100 | as much as possible.

00:17:16.580 | And indeed, this is a serious issue.

00:17:18.040 | It's not just about a few sniffles and watery eyes.

00:17:20.460 | There's an enormous financial and mental health cost

00:17:23.420 | and physical health cost to people getting the cold.

00:17:26.300 | And it's not just about people who are immune compromised

00:17:28.400 | or elderly people.

00:17:29.620 | What we're generally referring to as the cold today

00:17:32.460 | can be mild, it can be moderate,

00:17:34.360 | it can also be very severe,

00:17:35.840 | and it can exacerbate other health issues that people have.

00:17:38.560 | And we'll talk about that a little bit later

00:17:40.100 | and how to offset some of those health issues.

00:17:42.860 | Okay, so now let's talk about the flu virus.

00:17:44.760 | The flu virus is, as I mentioned, a virus.

00:17:47.860 | And just like with the cold,

00:17:49.320 | there are different serotypes of the flu virus.

00:17:52.100 | There are also different general categories of flu virus.

00:17:55.100 | So you've got your A-type flu viruses,

00:17:57.840 | your B-type flu viruses, and your C-type flu viruses.

00:18:00.960 | And by the way, I'm saying flu viruses,

00:18:02.840 | but of course I'm referring to influenza,

00:18:05.440 | but it's just kind of commonplace nowadays

00:18:07.880 | to refer to influenza as the flu.

00:18:10.960 | Similar to cold viruses,

00:18:12.580 | the different types of flu viruses

00:18:14.680 | exist based on the different types of proteins

00:18:17.360 | that they express on their surface.

00:18:19.200 | In fact, in the news over the last few years,

00:18:21.520 | there have been a number of different flu virus strains

00:18:24.100 | that have been described

00:18:26.100 | according to their surface protein characteristics.

00:18:29.100 | Things like the H1N1 virus.

00:18:31.600 | What is H1N1?

00:18:32.960 | H1N1 describes the different types of proteins

00:18:36.400 | that are expressed on the surface

00:18:37.960 | of that particular flu virus.

00:18:40.020 | Now, the most common type of flu viruses

00:18:41.760 | are in that A category of flus.

00:18:44.180 | This is the type of flu that caused the Spanish flu.

00:18:46.880 | Now, the Spanish flu,

00:18:47.840 | which by the way, did not originate in Spain,

00:18:50.100 | people think it probably originated in New York

00:18:52.760 | or perhaps elsewhere, but certainly not in Spain,

00:18:55.160 | killed anywhere from 17 to 50 million people,

00:18:59.160 | depending on which literature you read.

00:19:01.480 | That's an enormous number of people.

00:19:03.200 | And it occurred in four different waves of infection

00:19:06.840 | that occurred between the years 1918 and 1920.

00:19:10.840 | The Spanish flu was a type A H1N1 virus.

00:19:14.360 | And actually, it's worth noting that this winter season,

00:19:17.200 | there have been some cases of H1N1 already reported

00:19:20.200 | in the United States and elsewhere.

00:19:22.080 | Now, of course, the goal is always to contain

00:19:24.480 | the propagation of those flu viruses.

00:19:27.020 | And that is done through a number of different approaches.

00:19:30.480 | The best and most reliable approach, of course,

00:19:32.840 | is to not come into contact with somebody

00:19:35.040 | that is carrying the H1N1 or any other type of flu virus.

00:19:39.040 | However, based on the way that the flu virus

00:19:42.200 | infects the body, the way that the symptoms emerge,

00:19:44.400 | and the ways that viruses propagate,

00:19:47.200 | that can't always be avoided.

00:19:49.180 | One thing to know, and I consider this a fortunate aspect

00:19:51.640 | of flu virus biology, is that the flu virus,

00:19:54.560 | unlike the cold virus, can only exist on surfaces

00:19:58.200 | for about two hours.

00:19:59.840 | After about two hours, it tends to die off.

00:20:02.200 | So the flu virus is most typically passed

00:20:04.320 | by human-human contact, or coming into contact

00:20:07.280 | that is walking into a cloud of somebody's sneeze

00:20:09.780 | that contains flu virus, or somebody's cough

00:20:12.320 | that contains flu virus.

00:20:13.840 | And yes, it is possible that shaking someone's hand

00:20:17.180 | could actually introduce flu virus to your hand,

00:20:19.760 | and then if you wipe your eyes,

00:20:21.400 | or I'll talk about a few other portals of entry

00:20:23.800 | for the flu virus and cold virus in a few minutes,

00:20:26.200 | can get into your body and infect you.

00:20:27.800 | And yes, you can pick up the flu virus from surfaces.

00:20:30.720 | However, that is far less common

00:20:32.560 | than the flu virus passing from human-human contact.

00:20:35.600 | Now, there aren't as many different types of flu virus

00:20:38.240 | as there are types of cold virus,

00:20:39.880 | and that's why there have been attempts

00:20:41.740 | at making flu vaccines, or so-called flu shots.

00:20:45.540 | I think most people are familiar with the signs

00:20:47.240 | and advertisements online and in the workplace

00:20:49.480 | and school saying, "Get your flu shot this season."

00:20:52.240 | The reason that flu shots can exist at all

00:20:54.520 | is because there are limited enough types of flu virus

00:20:58.120 | present in a given year that specific vaccines,

00:21:02.240 | that is flu shots, can be generated

00:21:04.160 | against that particular strain of the flu virus.

00:21:07.440 | So how effective is the flu shot?

00:21:09.520 | And I want to be very specific here.

00:21:11.420 | When we say the flu shot, singular,

00:21:13.760 | it sort of implies that there's one flu shot

00:21:15.700 | that can combat all the different types of flu.

00:21:18.360 | And as you just learned, that is not the case.

00:21:20.480 | So we probably should be saying the flu shots,

00:21:23.520 | but just for sake of simplicity, when I say the flu shot,

00:21:26.220 | I mean the flu shot that's given in a given flu season

00:21:30.240 | that is directed at specific strains of the flu,

00:21:33.240 | because researchers have determined

00:21:34.760 | that that particular strain of flu or strains of flu

00:21:38.640 | are the ones that are most abundant

00:21:40.440 | for that particular flu season.

00:21:42.360 | Studies have shown that getting the flu shot

00:21:44.360 | reduces one's risk of contracting the particular flu

00:21:47.640 | that is most abundant that season by about 40 to 60%.

00:21:52.040 | But of course, the flu shot is completely ineffective

00:21:54.760 | at combating any other forms of the flu virus,

00:21:57.300 | and of course, colds or other types

00:21:59.080 | of upper respiratory infections.

00:22:00.900 | Studies have also shown that taking the flu shot

00:22:03.220 | can reduce the severity of one's symptoms

00:22:05.440 | if they in fact get the flu anyway.

00:22:07.960 | Now, personally, I don't typically get the flu shot.

00:22:10.880 | And the reason for that is that I don't tend

00:22:12.940 | to go into environments where I am particularly susceptible

00:22:15.960 | to getting the flu.

00:22:17.080 | I don't work in a hospital or a clinic.

00:22:19.200 | I don't tend to interact with large numbers of people

00:22:21.240 | on a daily basis.

00:22:22.620 | So for me, I've opted not to get the flu shot.

00:22:25.320 | Now, that doesn't mean that I've never contracted the flu.

00:22:28.160 | As I mentioned earlier, I tend to get sick

00:22:30.420 | with a cold or flu about once every 18 to 24 months.

00:22:34.180 | And the severity of that colder flu has ranged from,

00:22:37.080 | you know, at one point, a very high fever in one case,

00:22:39.900 | but typically a moderate fever

00:22:41.780 | and the usual symptoms of malaise

00:22:43.580 | that we've been discussing.

00:22:44.900 | And I've managed to get over those

00:22:46.460 | without having taken the flu shot pretty easily.

00:22:48.860 | Now, of course, we also don't know

00:22:50.760 | that those were actually flus.

00:22:52.620 | Despite the distinct differences

00:22:53.920 | between the symptoms of cold and flu,

00:22:56.240 | most people don't really know

00:22:57.620 | whether or not they have a cold or flu.

00:22:59.640 | So this is another thing to think about

00:23:01.140 | when considering whether or not to get the flu shot.

00:23:03.520 | Ultimately, because at least to my knowledge,

00:23:05.980 | most workplaces do not mandate that people get the flu shot.

00:23:09.080 | I could be wrong about certain workplaces,

00:23:10.880 | but my experience is that most workplaces do not mandate

00:23:14.240 | that people get the flu shot.

00:23:15.920 | When you take the flu shot, you're really hedging a bet.

00:23:18.140 | You're hedging a bet against the fact

00:23:19.580 | that you will be or not be exposed

00:23:22.140 | to that particular strain of flu virus

00:23:24.560 | that's most abundant that season

00:23:26.100 | or strains of flu virus that are most abundant that season,

00:23:29.140 | and that the flu shot that you're taking

00:23:31.340 | is directed at those particular strains.

00:23:33.900 | So again, in my case, I don't tend to take the flu shot,

00:23:36.460 | but of course you need to make the decision

00:23:38.060 | that's right for you.

00:23:39.360 | For instance, if you have family members

00:23:41.180 | that are immune compromised, or you work in a school,

00:23:44.060 | or you think that you are exposed to a lot of flus,

00:23:47.080 | or you're concerned about transmitting flu

00:23:49.020 | to any one individual or group of individuals,

00:23:51.620 | those are all things that need to be taken

00:23:53.140 | into consideration, and of course, speak to your physician.

00:23:56.280 | I will also say this, which is that I mentioned

00:23:58.560 | that I've tended to catch colds or flus

00:24:00.500 | at a rate of about once every 18 to 24 months.

00:24:03.860 | And when I say a cold or flu, I mean a serious one,

00:24:06.420 | one that keeps me in bed where I have a fever

00:24:08.220 | and I'm sweating.

00:24:09.060 | What I have done and I continue to do

00:24:10.700 | is because I pay pretty close attention

00:24:14.180 | to how well I'm sleeping or different life events,

00:24:16.520 | my different workouts, et cetera,

00:24:17.980 | and I put those into my calendar

00:24:19.340 | and I have a shorthand to do that,

00:24:20.620 | so it only takes about 30 seconds each day.

00:24:22.600 | Okay, did this work out?

00:24:23.640 | It was kind of level seven out of 10 intensity.

00:24:25.900 | Got good sleep last night or poor sleep,

00:24:27.740 | and I know what good and poor sleep is for me.

00:24:30.060 | I mean, that's about the level

00:24:31.100 | that I'm charting these things.

00:24:32.300 | I have been able to go back and look at the events

00:24:35.240 | preceding when I've come down with a cold or flu.

00:24:37.620 | Again, I don't know whether or not it was a cold or a flu,

00:24:39.540 | but before I got sick, and I've seen, for instance,

00:24:42.940 | like if I've ever done two hard workouts in a day,

00:24:45.820 | something I never do any longer,

00:24:47.780 | I've tended to get sick after that.

00:24:49.540 | If I've tended to do hard workouts

00:24:52.100 | and then expose myself to cold temperatures while traveling,

00:24:55.860 | especially traveling overseas,

00:24:57.420 | that tended to precede those colds or flus,

00:24:59.380 | which again, for me, are very seldom.

00:25:01.100 | So it's a limited data set.

00:25:02.280 | This is entirely anecdotal,

00:25:04.180 | meaning related to my own history of getting colds or flus,

00:25:08.300 | but it's something that I actually recommend people do,

00:25:10.380 | which is to pay attention

00:25:12.660 | to when you first started getting symptoms,

00:25:15.260 | pay attention to when you got over

00:25:16.740 | a given what you think is a cold or flu,

00:25:18.860 | and then to look at what was happening

00:25:20.280 | in the days before in that day.

00:25:22.060 | I don't think it's possible to do hyper precise forensics

00:25:25.500 | on a cold or flu, right?

00:25:26.760 | I mean, you could have gone into the gas station,

00:25:29.660 | put your credit card in the machine

00:25:31.660 | to grab a drink out of the refrigerator

00:25:33.580 | and picked up a cold or flu

00:25:34.580 | from the handle of the refrigerator

00:25:36.300 | or from the credit card machine,

00:25:37.860 | or even from the gas pump.

00:25:38.980 | You simply don't know.

00:25:40.400 | However, if you look at the pattern of behavior,

00:25:43.260 | travel, sleep, exercise,

00:25:45.420 | sorts of interactions you were having

00:25:46.820 | prior to getting a bad cold or flu,

00:25:49.180 | chances are you're gonna learn something interesting

00:25:51.000 | and be able to avoid getting a serious cold or flu,

00:25:53.780 | at least to some extent going forward.

00:25:56.080 | And I've done that, I think fairly successfully

00:25:57.920 | because I can tell you

00:25:59.380 | that the frequency of colds or flus

00:26:00.900 | that I've come down with

00:26:02.180 | has indeed been dropping from year to year.

00:26:05.140 | So whereas a decade ago,

00:26:06.300 | I tended to get colds or flus probably about once a year,

00:26:09.340 | and in some cases even twice a year,

00:26:11.180 | although that was pretty rare,

00:26:12.820 | that really expanded to about once every 18 months.

00:26:15.900 | And then in the last five years,

00:26:17.540 | I think I've gotten sick two times pretty badly

00:26:20.740 | with a cold or flu,

00:26:21.740 | and then once with a kind of mild cold or flu.

00:26:24.300 | So I tell you all that just as an example

00:26:26.420 | of how you can start to think about

00:26:27.660 | how your immune system interacts

00:26:29.200 | with different types of behaviors,

00:26:31.080 | different types of situations,

00:26:32.940 | such that you can learn something about your immune system

00:26:35.380 | and what's going to best protect you

00:26:37.180 | against getting colds and flus going forward,

00:26:39.180 | which of course is a great thing to do

00:26:40.860 | because we all think that we can get out there,

00:26:43.100 | be around people that are coughing and sneezing.

00:26:44.780 | We can go to the gym when it's crowded in winter.

00:26:46.580 | Oh, that person over there is coughing,

00:26:48.680 | but I'm going to just stay a few feet away, no big deal.

00:26:51.220 | And while I don't want to turn anyone into hypochondriacs,

00:26:53.900 | that's how you get infected.

00:26:55.380 | That's how you get a cold or flu.

00:26:56.520 | And at the same time,

00:26:57.580 | I don't think anyone should get to the point

00:26:59.860 | where they're afraid to go into a gym

00:27:01.620 | or afraid to go to the workplace.

00:27:03.080 | But I will say once again,

00:27:04.560 | if you're sick with a cold or flu,

00:27:05.820 | if you are coughing, sneezing, blowing your nose,

00:27:07.980 | runny eyes, and you're walking into work

00:27:10.760 | or the gym or onto public transportation,

00:27:12.940 | and you're telling people I'm not contagious, you're lying.

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00:27:17.940 | and thank one of our sponsors, and that's AG1.

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00:27:25.820 | I started taking AG1 way back in 2012.

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00:27:30.200 | and the reason I still take it every day

00:27:31.980 | is that it ensures that I meet all of my quotas

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00:27:40.500 | Now, gut health is something that over the last 10 years

00:27:42.960 | we realized is not just important

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00:27:55.460 | for proper brain functioning.

00:27:57.320 | Now, of course, I strive to consume healthy whole foods

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00:28:19.300 | if they were to take just one supplement,

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00:28:43.720 | Now, the diabolical thing about the flu virus

00:28:45.920 | is that just like the diabolical thing about the cold virus,

00:28:49.840 | you start shedding virus, that is you are contagious,

00:28:53.340 | about 24 hours prior to the onset of first symptoms for you.

00:28:57.900 | So that means that you can be a flu viral vector

00:29:01.140 | even when you aren't having symptoms.

00:29:03.740 | That's just the unfortunate aspect of these viruses.

00:29:06.440 | They're very clever.

00:29:07.280 | They don't have brains, but these viruses have adapted

00:29:09.980 | to propagate from host to host to host.

00:29:12.620 | They have a drive to continue to stay alive

00:29:16.340 | and to infect more hosts.

00:29:18.260 | So even though they don't have a brain,

00:29:19.780 | they have a sort of, let's call it viral intelligence.

00:29:23.100 | And as I've said several times now,

00:29:24.600 | if you are still exhibiting symptoms of the cold or flu,

00:29:27.340 | you are contagious.

00:29:29.100 | However, with respect to the flu,

00:29:31.940 | you are most contagious during the three days

00:29:34.860 | when you feel the absolute worst,

00:29:36.580 | when your fever is at its worst.

00:29:38.480 | We'll talk about how to deal with fever a little bit later.

00:29:40.580 | When you are coughing and sneezing, headache, all of that,

00:29:43.140 | when that is at its peak,

00:29:44.720 | that is when you are most contagious.

00:29:47.460 | So again, I realized that people can't always avoid contact

00:29:50.780 | with other people, you know, you live under the same roof,

00:29:53.720 | caretakers interacting with the person

00:29:56.420 | that has the cold or flu.

00:29:57.500 | And I do want to remind you something I said earlier,

00:29:59.960 | which is just because you come into contact

00:30:01.840 | with a cold or flu does not necessarily mean

00:30:04.040 | that you will come down with that is be infected

00:30:06.640 | by a cold or flu.

00:30:07.960 | Whether or not you come down with a cold or flu

00:30:10.200 | is of course dependent on whether or not

00:30:13.840 | you come into contact with it.

00:30:15.040 | You can't catch a cold or flu

00:30:16.280 | that you've never come into contact with,

00:30:17.600 | just like you can't get eaten by a shark

00:30:19.080 | if you never go in the ocean.

00:30:20.400 | However, the probability of coming down

00:30:23.320 | with that cold or flu,

00:30:24.160 | of it getting past your immune system barriers

00:30:27.360 | and infecting you is going to be strongly dictated

00:30:30.560 | by the different aspects of your immune system

00:30:33.400 | for which there are three major aspects,

00:30:35.800 | which we'll talk about next.

00:30:37.200 | And of course, the things that you do

00:30:39.340 | to bolster those three aspects of your immune system.

00:30:42.240 | Okay, let's talk about your immune system.

00:30:44.400 | And I have to confess that even though I've spent

00:30:46.440 | well over three decades being a student of and researcher

00:30:49.560 | of the nervous system, the immune system is oh so cool.

00:30:53.080 | And I say that because it has this incredible elegance

00:30:56.600 | and logic to it.

00:30:57.720 | It basically consists of three major lines of defense.

00:31:01.180 | There's a physical barrier or rather a set

00:31:03.720 | of physical barriers that exist between the organs

00:31:06.540 | of your body and the outside world.

00:31:08.480 | And you're probably immediately thinking skin.

00:31:10.640 | And yes, indeed, it includes your skin,

00:31:12.880 | but also some interesting things like the mucosal lining

00:31:15.680 | of your nose and mouth, and even some of the liquids

00:31:18.260 | that are on the surface of your eyes.

00:31:20.020 | We'll talk about those in a moment.

00:31:21.540 | Then there's a second line of defense,

00:31:23.640 | which is for any virus or bacteria or fungus

00:31:27.300 | for that matter, but today we're talking about viruses,

00:31:29.360 | cold and flu viruses.

00:31:30.880 | Any viruses that get past the physical barrier of your skin

00:31:34.180 | and the mucosal lining of particular regions of your body,

00:31:37.460 | well then you have what's called the innate immune system.

00:31:40.060 | The innate immune system is this very generalized

00:31:42.780 | response system.

00:31:43.960 | It's general in the sense that it deploys a basic set

00:31:46.760 | of neurochemicals that are not specific

00:31:49.360 | to the particular virus that's made it into your body.

00:31:52.840 | So not only is it not specific to a particular serotype

00:31:55.820 | of the cold or a different type of flu virus,

00:31:58.920 | but it's not even discriminating between cold or flu virus.

00:32:01.840 | This thing we call the innate immune system

00:32:03.900 | is a generalized response system to go and combat viruses.

00:32:08.140 | So it could be a cold, it could be a flu,

00:32:09.600 | it could be a bacteria, it could be a fungus,

00:32:11.640 | it could even be a physical object,

00:32:13.180 | and your innate immune system responds by saying,

00:32:15.340 | "Okay, let's go deal with this."

00:32:17.740 | Now, the third component of your immune system

00:32:19.440 | is what's called the adaptive immune system,

00:32:21.480 | and I alluded to this aspect of your immune system

00:32:23.440 | a little bit earlier.

00:32:24.540 | The adaptive immune system is the aspect

00:32:26.660 | of your immune system that recognizes,

00:32:29.560 | because the innate immune system told it,

00:32:31.820 | that something has infected the body at some level,

00:32:35.060 | at some organ or set of organs, and there's an emergency.

00:32:38.660 | And the adaptive immune system goes in

00:32:41.140 | and in a very targeted way, figures out what sorts

00:32:44.260 | of proteins it needs to produce, that is antibodies,

00:32:47.300 | to combat that specific serotype of virus.

00:32:51.260 | Okay, so the immune system has a physical barrier component,

00:32:54.500 | and it's not just skin, some other things as well.

00:32:57.340 | You've got your innate immune system,

00:32:59.160 | which is this generalized response system,

00:33:00.940 | and then there's the adaptive immune system.

00:33:02.980 | Let's talk about the physical barrier component first.

00:33:05.540 | And this is actually a good opportunity

00:33:06.900 | for us to just take a brief step back and realize

00:33:09.660 | that anytime we're talking about our physiology,

00:33:12.500 | there's going to be a mechanical set of features,

00:33:15.020 | and there's going to be a chemical set of features.

00:33:17.620 | So right now we're talking about the immune system,

00:33:19.480 | and the mechanical feature, or the physical feature

00:33:21.860 | of the immune system, is this barrier

00:33:24.020 | between the organs of our body and the outside world.

00:33:26.600 | And the most obvious of those is the skin.

00:33:29.100 | You are contained in this bag of stuff that we call skin.

00:33:32.140 | The skin isn't just for putting clothing on

00:33:34.940 | and for adorning with jewelry or tattoos,

00:33:37.460 | if that's your thing, watches, et cetera.

00:33:40.180 | Your skin is a living organ in and of itself.

00:33:43.180 | I think we're most accustomed to thinking about the heart

00:33:44.820 | and the lungs and the liver and the brain

00:33:46.060 | as organs of the body, but the skin is an organ

00:33:48.140 | of the body as well.

00:33:49.420 | It has a bunch of different layers of cells

00:33:52.000 | from the outside to the inside.

00:33:53.840 | Actually, the skin cells themselves are made

00:33:56.300 | in the deeper layers of the skin,

00:33:57.400 | and they migrate out towards the surface of the skin,

00:33:59.440 | and at the surface of the skin, on top of those cells

00:34:02.720 | and made by those cells are different types of chemicals

00:34:06.280 | that actually serve as antibacterial and antiviral agents,

00:34:09.780 | meaning if a cold virus or flu virus

00:34:12.100 | or other type of virus lands on the skin,

00:34:13.880 | it can neutralize and kill that virus.

00:34:16.420 | So your skin is a very important physical barrier

00:34:19.500 | against viruses such as the cold or flu virus

00:34:21.740 | getting into your body and infecting other cells and tissues.

00:34:25.140 | Now, your skin is not contiguous,

00:34:27.160 | meaning there are holes in it.

00:34:28.800 | So let's think about those holes for a second.

00:34:30.900 | As we go from head to foot, it's pretty obvious

00:34:34.560 | that your eyes have these two openings,

00:34:37.040 | and those are openings in your skin, right?

00:34:40.740 | As you open your eyelids, beneath there are your corneas,

00:34:45.040 | the shiny part of your eyes,

00:34:46.180 | and then a little bit further back,

00:34:47.540 | at the back inner lining of your eyeball,

00:34:49.680 | you have a very thin three-cell layer thick piece of tissue

00:34:53.320 | that we call the neural retina.

00:34:54.520 | And I say this because the neural retina

00:34:56.260 | is actually a piece of your brain.

00:34:57.900 | So you have two pieces of brain

00:34:59.080 | that line the back of your eyes,

00:35:00.360 | and that's the light sensing tissue

00:35:01.640 | in the back of your eyes.

00:35:02.480 | Now, I say this because what this means

00:35:04.800 | is that it's a very short distance

00:35:06.820 | between the opening of your skin

00:35:08.160 | that we call your eyelids and your brain.

00:35:10.420 | Now, most of the brain, of course,

00:35:11.420 | is contained in the cranial vault

00:35:12.920 | within what most people call the skull,

00:35:15.220 | but your brain isn't far away

00:35:17.000 | from those openings that we call your eyelids.

00:35:19.640 | So as a consequence, on the surface of your eyes,

00:35:21.840 | those corneas, the shiny part of your eyes on the outside,

00:35:25.560 | there are a bunch of different chemical features.

00:35:27.960 | There are tears that are made by your lacrimal glands,

00:35:31.040 | but there are also a lot of antibacterial agents

00:35:33.760 | that actively kill off stuff

00:35:35.840 | that could potentially infect your body,

00:35:37.600 | could make it into your body, maybe even into your brain.

00:35:40.400 | If you've ever woken up in the morning

00:35:41.720 | and you have some crust on your eyes,

00:35:43.600 | and you look at that crust, that kind of yellowy stuff,

00:35:45.840 | sometimes it's yellow, I know this is kind of gross,

00:35:47.360 | that's actually dead bacteria that your eyes have successfully

00:35:50.600 | defeated during your night's sleep.

00:35:53.000 | So when you wipe those away,

00:35:53.920 | you're taking the casualties of a war

00:35:56.000 | that you won during your night's sleep,

00:35:58.400 | and you're whisking those away.

00:36:00.680 | Now, as we descend a little bit further down the face,

00:36:03.000 | there are, of course, the nostril openings,

00:36:04.720 | and the nostril openings tend to be kind of sticky, right?

00:36:07.280 | They're moist, sticky, and warm.

00:36:08.920 | You don't have to put your fingers up them right now,

00:36:10.440 | you just know they're moist, sticky, and warm.

00:36:12.280 | Get your fingers out of your nose, please.

00:36:14.000 | The mucosal lining of your nose

00:36:15.560 | is actually a very important substance

00:36:17.840 | that is sticky in order to trap viruses

00:36:20.200 | such as colds and flu viruses,

00:36:21.680 | and then chemical components

00:36:23.120 | within the mucosal lining can neutralize them.

00:36:25.320 | That's the best case scenario.

00:36:26.520 | There are, of course, scenarios in which the cold

00:36:28.800 | or flu virus takes residence in your mucosal lining

00:36:31.200 | and it can make its way back into your sinus passages

00:36:34.520 | and can then infect other cells and tissues of your body

00:36:37.360 | because the virus replicates and spreads throughout the body.

00:36:40.080 | And then going a little bit further down,

00:36:42.080 | I realize this is obvious, you have your mouth.

00:36:43.880 | And what's really interesting is that your mouth

00:36:45.800 | also has mucosal lining, which is sticky,

00:36:48.000 | and it has chemical components

00:36:49.320 | to neutralize incoming viruses.

00:36:52.120 | But we know that the type of mucus

00:36:55.380 | and the type of bacteria that live in your nose and mouth

00:36:58.360 | that, by the way, are very healthy for you

00:37:00.040 | and encourage healthy immune system function,

00:37:02.600 | that is, act as ways to neutralize viruses

00:37:05.360 | within your nose and mouth, are very different.

00:37:07.720 | So your nose and your mouth,

00:37:09.200 | they seem similar at the level of,

00:37:11.040 | okay, well, it's warm and sticky in there, there's mucus,

00:37:13.440 | but they are very, very different tissues.

00:37:15.600 | In fact, if you think about your mouth,

00:37:17.440 | it's this incredible structure that not only lets you eat

00:37:20.600 | and breathe in and out through,

00:37:21.840 | although I suggest most people be nasal breathers

00:37:24.160 | for most of the time of their day and night, if you can.

00:37:26.800 | Of course, sometimes you have to mouth breathe.

00:37:28.340 | But keep this in mind,

00:37:29.800 | you have this big opening in the front of your face

00:37:32.240 | and bacteria are getting in there all day long.

00:37:35.320 | Viruses are getting in there all day long.

00:37:37.880 | And in most cases,

00:37:38.760 | you are successfully combating those viruses and bacteria

00:37:42.600 | because the mucosal lining of your mouth

00:37:45.200 | and your nose for that matter, and the microbiota,

00:37:49.360 | those little microorganisms that have taken residence

00:37:52.480 | in your nose and mouth are helping to contribute

00:37:54.680 | to fight off bacteria and viruses,

00:37:56.560 | provided the microbiota there are diverse

00:37:59.640 | and are of the type you want,

00:38:00.840 | which we'll talk a little bit more about later.

00:38:03.360 | And then descending further down the body,

00:38:04.880 | of course, there are other openings into your skin barrier,

00:38:09.000 | namely the urethra of the penis or vagina,

00:38:13.000 | and of course the vaginal canal.

00:38:15.040 | So the genitals, of course, have their own mucosal lining.

00:38:17.960 | And as you can imagine,

00:38:19.780 | it is distinct in terms of its physical makeup

00:38:22.560 | and its chemical makeup from the mucosal lining

00:38:25.760 | of your nasal passages and mouth.

00:38:28.280 | And then of course we have the rectum and anus,

00:38:30.360 | which is the outflow pathway of your intestines,

00:38:33.200 | which are post-digestive.

00:38:35.320 | And there too, you have a mucosal lining for which,

00:38:38.240 | yes, certain types of viruses and bacteria

00:38:40.360 | can infect that area.

00:38:41.540 | But what we know is that the primary entry sites,

00:38:43.780 | the most common ways in which colds and flus

00:38:46.800 | get into your body,

00:38:47.960 | the way they breach that physical barrier

00:38:49.640 | that we call your skin,

00:38:51.040 | is through your eyes, your nose, or your mouth.

00:38:54.240 | And there are a lot of data, some of which conflict,

00:38:57.040 | and frankly, there need to be more data

00:38:58.900 | in order to really resolve this,

00:39:00.400 | but it seems like the primary entry site

00:39:02.840 | for viruses to get into the body

00:39:05.320 | tends to be the eyes or the mouth.

00:39:08.140 | And we can get into some of the reasons

00:39:09.500 | why that would be so.

00:39:10.780 | But if you think back to our conversation

00:39:12.280 | about the way that colds and flus exist in the world,

00:39:14.780 | either as aerosols or on surfaces of objects

00:39:18.940 | or on surfaces of skin,

00:39:20.440 | well then what I'm about to tell you next

00:39:22.180 | will make it oh so obvious why the eyes and the mouth

00:39:25.540 | are the primary sites of entry for colds and flus.

00:39:27.840 | And if you keep that in mind, there's a good chance

00:39:30.200 | you can avoid a lot of colds or flus

00:39:32.140 | that you would otherwise catch.

00:39:33.940 | Okay, so before I talk about the important roles

00:39:35.980 | of the innate and the adaptive immune system

00:39:38.160 | in keeping colds and flus at bay,

00:39:41.220 | I'll tell you that you have a problem.

00:39:43.140 | And that problem is that you tend to touch your eyes

00:39:47.780 | very often.

00:39:48.660 | In fact, you tend to touch your eyes most often

00:39:52.120 | after you shook somebody else's hand.

00:39:54.860 | Now, why am I picking on you?

00:39:56.540 | Well, in fact, I'm not.

00:39:57.700 | I'm picking on all of you and I'm picking on myself included

00:40:00.780 | because there have been several studies now,

00:40:04.280 | primarily from Noam Sobel's lab at the Weizmann Institute

00:40:07.340 | showing that when people encounter another person

00:40:10.680 | and they shake their hand, they either touch their eyes

00:40:13.720 | or touch another region of their face

00:40:15.920 | very close to the eyes

00:40:17.580 | or that they touched their hand to their mouth.

00:40:20.860 | Now, there are a bunch of theories as to why people do this.

00:40:23.820 | There's the idea that people are actually sniffing

00:40:25.800 | their own hand and in particular sniffing their own hand

00:40:29.100 | more often after they shake someone else's hand

00:40:32.320 | as a way to detect what chemo signals

00:40:35.100 | exist on the other person,

00:40:36.220 | not necessarily conscious smelling

00:40:38.380 | of the other person's smell,

00:40:39.900 | but rather some sort of unconscious mechanism

00:40:42.900 | by which we take the chemicals

00:40:44.220 | of the person we come into contact with

00:40:46.140 | and we bring them to our nose, our eyes,

00:40:48.500 | or in some cases our upper lip.

00:40:50.260 | And that our olfactory system, that is the neurons

00:40:52.720 | that exist just behind the back of our nose

00:40:55.740 | are processing that information

00:40:57.160 | and getting all sorts of important information

00:41:00.340 | about how stressed the other person is,

00:41:02.180 | their hormones, whether or not we recognize them,

00:41:05.900 | the fact that they are different from us, that's right.

00:41:08.820 | We are also smelling ourselves all day long.

00:41:11.500 | Noam's lab has shown this,

00:41:12.620 | that people are kind of walking around

00:41:14.800 | in their own odor cloud.

00:41:16.540 | We tend to touch our armpits.

00:41:18.020 | We tend to touch different aspects of our body, yes,

00:41:20.740 | and smell ourselves multiple times throughout the day.

00:41:23.380 | This is all being done unconsciously.

00:41:25.340 | I suppose some people are doing it consciously.

00:41:27.020 | And that there's a lot of information

00:41:29.120 | about our physiology and health.

00:41:31.300 | And when we do this after shaking somebody's hand,

00:41:33.440 | that there's a lot of information

00:41:35.180 | about the other person's physiology and health,

00:41:37.820 | that our nervous system, our olfactory system

00:41:40.120 | and deep parts of our brain

00:41:41.900 | that are involved in primitive type behaviors,

00:41:43.500 | but also some pretty sophisticated behaviors

00:41:45.380 | are taking into account.

00:41:46.700 | Now, Noam Sobel was a guest on the Huberman Lab Podcast.

00:41:49.180 | I encourage you to check out that episode if you have time.

00:41:51.620 | It's a fascinating voyage into the olfactory system

00:41:54.780 | and not just conscious smelling or sniffing of things.

00:41:57.720 | So we go, oh, that smells good, or that smells bad,

00:42:00.020 | or that person is somebody I want to mate with

00:42:02.660 | or hang out with or avoid.

00:42:04.180 | It's also unconscious processing

00:42:05.860 | of so-called chemo signals, chemical signals.

00:42:08.880 | But the reason I'm bringing up these studies now

00:42:10.540 | in the context of colds and flus

00:42:11.900 | and how to avoid getting colds and flus

00:42:14.060 | is as a reminder that we are pretty much wired

00:42:18.900 | to contact our own face with our own hands

00:42:22.300 | at the level of our eyes, nose, and upper lip

00:42:25.540 | and around the eyes very shortly

00:42:28.260 | after we touch somebody else's skin.

00:42:31.240 | And if you are mindful of it,

00:42:33.100 | you can actually avoid bringing colds or flus to your face.

00:42:37.000 | Now, in doing so, or you're going to short circuit

00:42:39.640 | a bunch of other important biological processes involved

00:42:42.220 | in understanding what's going on in your environment

00:42:44.660 | because you're not bringing in those smells,

00:42:46.780 | I suppose that's possible.

00:42:47.840 | But with respect to avoiding colds and flus,

00:42:49.980 | it seems like a pretty good trade off to me.

00:42:52.600 | So the point that I'm trying to make here

00:42:53.900 | is that in order for you to catch a cold or flu,

00:42:56.260 | that cold or flu virus, the little particles

00:42:58.780 | of cold and flu virus need to make it into your body.

00:43:01.500 | And the primary entry sites are eyes, nose, mouth,

00:43:04.540 | and the primary actions by which we bring colds

00:43:07.300 | and flu viruses to our eyes, nose, mouth

00:43:10.420 | are by touching other people or by touching other surfaces

00:43:14.340 | that have cold or flu virus.

00:43:15.960 | Just to remind you, cold virus can exist

00:43:17.980 | up to 24 hours on a given surface.

00:43:20.540 | Flu virus tends to die off

00:43:22.740 | after about two hours on a given surface.

00:43:25.140 | And we're bringing that to our face.

00:43:26.860 | We are literally bringing the virus to ourselves.

00:43:29.340 | So a little bit more conscious awareness about that fact

00:43:33.480 | means that you can probably avoid colds and flus

00:43:35.780 | to some extent.

00:43:36.620 | How much?

00:43:37.440 | Well, it's unclear.

00:43:39.220 | It's unclear because as you recall,

00:43:41.560 | some people have and are passing along cold or flu virus

00:43:44.620 | prior to any symptoms.

00:43:46.340 | And of course, it's possible that you can walk

00:43:49.140 | into an aerosol cloud of cold or flu virus

00:43:51.540 | even if a person isn't there

00:43:52.780 | and you don't come into contact with them.

00:43:54.100 | But some conscious awareness of these routes of passage

00:43:56.340 | for the cold or flu virus,

00:43:57.460 | I do believe can reduce the probability

00:44:00.260 | that you will catch a cold or flu.

00:44:02.020 | And of course, I'm not encouraging people to never touch.

00:44:04.420 | Touch is an important part of social connection

00:44:06.740 | and social bonding.

00:44:08.220 | But if you start to think about these portals of entry

00:44:10.100 | for the cold and flu virus into your body,

00:44:12.380 | well, then you perhaps might think twice

00:44:14.840 | before hugging someone, kissing them on the cheek

00:44:17.260 | during a time in which you're trying to actively avoid

00:44:19.380 | getting the cold or flu.

00:44:21.060 | Now, I feel a little bit funny about sharing this information

00:44:24.340 | because again, I don't want to encourage people

00:44:26.180 | to always be at arms distance, fake fist bumping,

00:44:29.900 | keeping a gap between them.

00:44:31.100 | Again, touch is an important component of social connection.

00:44:33.920 | But since today's topic is colds and flus

00:44:36.020 | and how to avoid getting colds and flus,

00:44:38.180 | just like you can't get eaten by a shark

00:44:40.320 | if you don't go in the ocean,

00:44:42.020 | there's a much lower probability

00:44:43.500 | that you're going to get a cold or flu

00:44:45.180 | if you're not touching a lot of hands

00:44:47.200 | and bringing those hands to your eyes, nose or mouth.

00:44:51.360 | I suppose one way around the sort of do I hug,

00:44:53.800 | do I shake hands thing is to just be conscious of the fact

00:44:56.920 | that when you shake somebody's hand

00:44:58.080 | that you're very likely to touch your eyes or face

00:45:00.760 | within the next 30 seconds or so.

00:45:02.560 | And maybe you end up being that person

00:45:04.320 | who puts some hand sanitizer on your hands.

00:45:06.440 | Sometimes that can feel a little awkward

00:45:07.680 | to do that right in front of somebody.

00:45:08.880 | You know, it's kind of sending a signal like,

00:45:10.000 | hey, I don't want you to infect me, but guess what?

00:45:12.000 | You don't want them to infect you.

00:45:13.520 | Okay, let's imagine that a cold or flu virus

00:45:16.400 | makes it into your system.

00:45:17.500 | It breaches the physical barrier of your skin

00:45:19.720 | and mucosal lining.

00:45:21.520 | Now, you have in mind all the different ways

00:45:24.360 | that could happen and all the different ways

00:45:25.760 | that could be prevented.

00:45:26.580 | But we are starting at a point here, a hypothetical point

00:45:29.280 | whereby that cold or flu virus has made it into your body.

00:45:33.720 | Your immune system has an absolutely

00:45:35.900 | exquisitely sophisticated way of knowing you versus other,

00:45:40.580 | meaning cells within your body that are of you

00:45:44.320 | and cells of your body that are from other organisms

00:45:48.120 | or viruses from the outside world.

00:45:50.680 | And when viruses such as a cold or flu virus

00:45:53.480 | are detected in your body,

00:45:55.980 | your body might not even recognize

00:45:57.660 | that it's a cold or flu virus.

00:45:59.240 | It might not even recognize that it's a virus at all.

00:46:01.640 | It just knows that this thing that's in me is of other.

00:46:05.640 | It's not me.

00:46:06.760 | I've never seen it before.

00:46:08.000 | This is not me.

00:46:08.840 | These are not my cells.

00:46:09.860 | These are not the chemicals that I'm producing.

00:46:12.000 | And your immune system is amazing in that way.

00:46:14.440 | And when it occurs,

00:46:16.700 | your innate immune system launches a response.

00:46:20.400 | What is that response?

00:46:21.600 | Well, first of all, the response is very rapid, right?

00:46:25.100 | Cold or flu makes it into your body

00:46:26.900 | and your innate immune system immediately

00:46:29.720 | or near immediately launches an attack

00:46:33.200 | on that invader or invaders.

00:46:35.820 | Because as soon as the virus gets into your body,

00:46:37.600 | it's going to start replicating as quickly as it can.

00:46:41.260 | What happens?

00:46:42.180 | White blood cells that your body produces

00:46:46.740 | will go to the sites where those viruses are.

00:46:49.620 | And by the way, those viruses are basically

00:46:52.540 | getting into cells of your body

00:46:54.040 | and then hijacking the genetic machinery of those cells

00:46:57.100 | in order to replicate within those cells

00:46:59.220 | and then exit those cells and then go infect more cells.

00:47:02.880 | That's how these viruses work.

00:47:05.140 | Your body's making white blood cells,

00:47:06.780 | things like neutrophils, natural killer cells, macrophages.

00:47:11.020 | These are what we call effector cells

00:47:13.120 | that act as a kind of ambulance system

00:47:15.100 | and go to the sites that those viruses exist

00:47:17.420 | and the cells that they've infected

00:47:19.100 | and start trying to physically barrier them in

00:47:22.740 | and also use specific chemical mechanisms

00:47:26.380 | to neutralize and kill those viruses.

00:47:28.460 | Again, anytime you're thinking about biology,

00:47:30.300 | think of mechanical features

00:47:32.200 | and chemical features of a response.

00:47:34.620 | Now, a key component of the innate immune system

00:47:36.700 | is what's called the complement system.

00:47:38.560 | Not complement like, oh, you look very nice today,

00:47:40.360 | but complement, okay, the complement system,

00:47:43.420 | which exists in the plasma within your blood.

00:47:46.400 | These are chemicals in your bloodstream

00:47:48.020 | that go and mark specific cells that have been infected

00:47:51.040 | or viruses with a signal, a chemical signal

00:47:54.500 | that essentially looks like an eat me signal

00:47:58.120 | to these other cell types of your immune system,

00:48:00.560 | such that those natural killer cells go through the body

00:48:04.660 | and go looking for the cells

00:48:05.840 | that have this eat me signal on them

00:48:07.100 | and try and destroy those particular cells.

00:48:09.660 | The other thing that your innate immune system does

00:48:11.960 | is that the cells that have been infected

00:48:14.700 | and that are undergoing damage,

00:48:16.000 | remember, they have cold or flu virus within them

00:48:18.300 | and they're hijacking the cellular machinery of those cells

00:48:21.260 | and using it to produce their own virus, more of the virus.

00:48:25.420 | And as a consequence, the genetic machinery of those cells

00:48:28.160 | is not able to do a bunch of other things

00:48:29.840 | that it normally can do, or at least not as well.

00:48:32.840 | Well, those cells that are really hurting

00:48:34.820 | release a help me signal.

00:48:37.660 | And then in response to that help me signal,

00:48:39.780 | your immune system releases what are called cytokines,

00:48:42.020 | things like interleukin-1, interleukin-6,

00:48:44.720 | tumor necrosis factor alpha,

00:48:46.520 | just fancy nerd speak names

00:48:48.420 | for different types of molecules

00:48:50.960 | that go to the site of infection

00:48:53.480 | and try to help or assist to remove that infection.

00:48:57.000 | And they also try to assist the repair of the cells

00:49:00.040 | that have been infected by those viruses.

00:49:02.380 | Now, one of the mechanical or physical consequences

00:49:05.220 | of these chemical signals like interleukin-1,

00:49:08.480 | interleukin-6, TNF alpha, again, those are all cytokines,

00:49:11.540 | being drawn to a particular cell

00:49:13.940 | or region of cells that have been infected

00:49:16.580 | is that it creates some physical swelling of the area.

00:49:20.100 | It impacts the vasculature,

00:49:21.660 | the veins and capillaries that feed that area.

00:49:24.900 | And in response to that, they put more blood there

00:49:26.780 | so you get some swelling or you'll get, in some cases,

00:49:30.840 | the release of histamines, right?

00:49:32.740 | We think of antihistamine drugs.

00:49:34.380 | Well, histamines are an aspect of your immune system.

00:49:36.620 | They move around in your body

00:49:37.660 | in these really cool cells called mast cells,

00:49:39.860 | M-A-S-T, mast cells.

00:49:41.300 | And when the histamines are released,

00:49:42.660 | that area becomes kind of hot and swelling.

00:49:44.860 | It's what we call edema.

00:49:46.020 | And that whole area is marked as really a site,

00:49:49.060 | just like a crash site on the side of the road.

00:49:50.700 | It's like, hey, we've got eat me signals

00:49:52.820 | to get the debris and the bad stuff out of here.

00:49:55.020 | Try to get those viruses out of here.

00:49:56.340 | We've got help me signals to try and help the injured cells,

00:49:58.940 | just like you would try and help people at a car crash.

00:50:00.900 | And there's a bunch of swelling,

00:50:02.380 | so there's additional blood flow.

00:50:03.900 | Sometimes there's some other physical features as well.

00:50:06.580 | Now, the important thing to know

00:50:07.540 | is that the innate immune system is very fast

00:50:09.980 | and it is agnostic to the type of infection.

00:50:13.340 | In fact, it doesn't even matter if it's a bacterial,

00:50:15.440 | physical, fungal, or viral infection,

00:50:17.860 | but it certainly isn't paying attention

00:50:19.500 | to the exact serotype of cold virus

00:50:21.580 | or whether or not it's an H1 influenza

00:50:23.700 | or another type of influenza.

00:50:25.260 | So the way to think about the innate immune system

00:50:27.020 | is that it is a very fast and nonspecific response

00:50:30.340 | to a viral or other type of invader.

00:50:33.100 | Now, that's all a bunch of biology,

00:50:34.700 | but if you think about it,

00:50:36.300 | let's imagine a scenario where you go to a party,

00:50:39.480 | hang out at the party,

00:50:40.600 | you don't see anyone coughing or sneezing,

00:50:42.440 | but maybe one person there has a cold virus

00:50:45.460 | or they have a flu virus and they aren't even aware of it.

00:50:47.900 | They're not going to come down with symptoms

00:50:48.980 | for another day or so.

00:50:49.980 | You talk to that person, you shake hands,

00:50:51.760 | maybe touch your eyes, maybe you don't,

00:50:54.100 | but you're exposed to that cold or flu virus.

00:50:56.740 | You go home, you go to sleep,

00:50:58.500 | you wake up the next morning, you feel fine.

00:51:00.160 | And then sometime in the next afternoon,

00:51:02.420 | you start to feel a little tickle in your throat

00:51:04.260 | and you start to feel just a little bit of fatigue

00:51:06.220 | or malaise.

00:51:07.820 | Do you have that cold or flu?

00:51:09.720 | Well, possibly, okay, we don't know for sure,

00:51:12.040 | but assuming that that cold or flu virus

00:51:13.900 | did indeed make it into your system,

00:51:16.140 | then your innate immune system is starting to create

00:51:19.600 | a set of responses that we talked about a moment ago,

00:51:22.860 | but it also tends to impact things

00:51:25.540 | at the level of your brain,

00:51:27.020 | such that you kind of feel like,

00:51:28.660 | I don't feel quite right.

00:51:29.900 | I feel like a little bit, I don't feel great.

00:51:33.300 | And there are a lot of reasons why you would feel that way,

00:51:35.260 | and we'll talk about those reasons a little bit later,

00:51:37.380 | but does that mean that you're necessarily coming down

00:51:39.740 | with a cold or flu?

00:51:41.220 | Well, technically, yes.

00:51:43.060 | Your innate immune system is deployed

00:51:44.700 | to fight this foreign viral invader,

00:51:47.240 | but whether or not you actually get a full-blown cold or flu

00:51:50.580 | or put differently,

00:51:52.700 | how severe that cold or flu infection is,

00:51:55.140 | it depends on whether or not your innate immune system

00:51:57.000 | can fight off that cold or flu at the outset.

00:51:59.480 | And indeed, there are many cases, we believe,

00:52:02.400 | where you get exposed to a cold or flu,

00:52:04.280 | it makes it into your body,

00:52:05.480 | but your innate immune system is sufficient to beat it,

00:52:09.040 | to fight it back.

00:52:10.460 | This is one of the reasons why it's so important

00:52:12.660 | that if you're starting to feel a bit under the weather

00:52:15.020 | and you think you're coming down with a cold or flu,

00:52:17.600 | that you do certain things in order to make sure

00:52:19.940 | that your innate immune system is both ready

00:52:22.900 | and that it can launch a full-scale attack

00:52:25.380 | on that cold or flu virus.

00:52:26.840 | We're going to talk about how to do that a little bit later.

00:52:28.820 | I'm not trying to withhold.

00:52:29.860 | It's just, it's important to understand

00:52:31.540 | that just because the virus makes it into your body,

00:52:34.020 | doesn't necessarily mean

00:52:35.260 | that you're going to get a full-blown cold or flu.

00:52:37.340 | And in fact, that innate immune system sometimes

00:52:39.760 | is sufficient to prevent that cold or flu

00:52:42.380 | from replicating enough

00:52:43.900 | that you get the full-blown set of symptoms.

00:52:46.420 | And that's kind of an ideal scenario.

00:52:47.920 | So we're definitely going to talk today about what to do

00:52:51.220 | if you start to feel a little bit of malaise,

00:52:54.440 | what to do if you discover that,

00:52:55.880 | oh, you know that person I was hanging out with

00:52:57.320 | at the party the night before,

00:52:59.260 | they're really sick with a cold or flu.

00:53:00.660 | Because there are things you can do

00:53:01.940 | to increase the probability

00:53:03.100 | that your innate immune system

00:53:05.360 | can handle the battle sufficiently

00:53:07.300 | such that you never have to get

00:53:08.600 | to the next component of the immune response,

00:53:10.760 | which is the adaptive immune response.

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00:54:14.580 | Okay, so the third layer of your immune system

00:54:17.340 | is your adaptive immune system,

00:54:19.280 | and this is an amazing aspect of you, okay?

00:54:23.460 | The stuff we talked about up until now,

00:54:24.980 | the physical barrier, the innate immune system, so, so cool,

00:54:28.700 | but the adaptive immune system is really a mindblower.

00:54:32.800 | The most important thing to understand

00:54:34.100 | about your adaptive immune system

00:54:35.940 | is that as the name suggests,

00:54:38.340 | its job is to create antibodies specific

00:54:41.740 | to the very intruder that made it into you

00:54:44.840 | and infected your cells,

00:54:45.900 | the very specific serotype of cold virus,

00:54:48.740 | the very specific type of influenza,

00:54:52.740 | such that you defeat that virus,

00:54:55.540 | but then in an amazing way,

00:54:57.920 | your adaptive immune system also maintains a memory

00:55:01.180 | of that battle and keeps within your body,

00:55:04.460 | believe it or not, within a population of stem cells,

00:55:07.300 | which are cells that can rise to more cells,

00:55:10.320 | such that if you ever encounter

00:55:12.900 | that same serotype of cold virus

00:55:15.420 | or same strain of influenza again,

00:55:18.660 | that your antibodies can immediately

00:55:21.300 | neutralize that colder flu virus.

00:55:23.500 | The adaptive immune system has the ability to make proteins

00:55:26.780 | that have a particular shape on their surface

00:55:29.300 | that matches the shape of the thing

00:55:32.300 | that your immune system is trying to kill.

00:55:35.340 | Now, the adaptive immune system has two basic phases.

00:55:39.620 | In the first phase, the adaptive immune system

00:55:41.780 | makes these things called immunoglobulins, IGs,

00:55:45.480 | and the immunoglobulins come in different forms.

00:55:47.220 | There's IgG, there's IgM,

00:55:49.340 | there are other types of IGs as well.

00:55:51.180 | For sake of today's discussion,

00:55:53.440 | know that the initial wave of antibodies

00:55:57.540 | that the adaptive immune system makes are of the IgM variety

00:56:01.280 | and the IgM antibodies can travel to

00:56:03.940 | and latch onto the surface of the colder flu virus

00:56:07.700 | and it matches it pretty well.

00:56:09.900 | It's not perfect, but it matches it pretty well.

00:56:12.140 | Think about, for instance,

00:56:13.800 | a particular serotype of cold virus or the H1N1 flu virus

00:56:17.280 | having a very particular contour on its surface.

00:56:21.480 | The IgM approximates that contour

00:56:24.240 | such that it's better at fighting that cold or flu virus

00:56:27.920 | than is the innate immune system,

00:56:30.020 | but it's not a perfect fit.

00:56:32.100 | However, the adaptive immune system

00:56:33.680 | doesn't stop with the production of those IgMs.

00:56:36.440 | The adaptive immune system takes that information

00:56:38.980 | about how precise or imprecise that fit is

00:56:42.240 | between the IgM antibody

00:56:43.800 | and the surface of that particular cold or flu virus,

00:56:46.160 | and then, in an amazing way,

00:56:49.400 | sends signals back to the stem cell populations

00:56:51.940 | in the bone marrow and other tissues,

00:56:53.720 | and then more antibodies come out of the IgG variety,

00:56:58.720 | and the IgG proteins are very specific

00:57:01.600 | to the shape of that particular cold virus or flu virus,

00:57:06.180 | such that the IgGs then can define to

00:57:10.920 | and neutralize those viral particles, okay?

00:57:14.080 | So when we talk about the immune system,

00:57:15.480 | we're talking about a physical barrier

00:57:17.000 | that, if it is breached, a cold or flu virus

00:57:21.900 | takes residence and starts to replicate.

00:57:23.840 | The innate immune system launches a generalized attack

00:57:26.880 | on that cold or flu virus,

00:57:28.400 | and then the adaptive immune system kicks in

00:57:30.920 | usually a couple days later,

00:57:32.960 | first with the production of antibodies

00:57:35.580 | that are pretty specific to the particular virus

00:57:38.980 | that happened to make it into the body and infect cells,

00:57:41.840 | but then there's a second wave of production of antibodies,

00:57:44.980 | and those antibodies are incredibly specific

00:57:47.360 | for that particular cold or flu virus,

00:57:49.080 | and, as I mentioned earlier,

00:57:50.880 | the adaptive immune system then acquires a memory

00:57:55.120 | of the specific fit between a given antibody that it made

00:57:59.260 | and the viral invader and the successful battle

00:58:02.080 | that those antibodies waged on that viral invader,

00:58:05.560 | and that memory is maintained such that,

00:58:07.440 | if the next week or the next season,

00:58:10.300 | you encounter the exact same serotype of cold virus

00:58:12.800 | or same type of flu virus,

00:58:15.360 | well, then you already have antibodies ready to be deployed.

00:58:18.620 | Sometimes the antibodies continue

00:58:20.480 | to circulate in your system.

00:58:22.220 | Sometimes you need to generate more of them,

00:58:24.320 | and the immune system is that amazing.

00:58:26.220 | It can actually send a message

00:58:28.120 | back to that stem cell population

00:58:29.620 | in the bone marrow or elsewhere,

00:58:31.080 | say, "Hey, listen, this virus that we beat

00:58:33.480 | a few weeks or months or years back, it's back.

00:58:36.320 | We need more antibodies," and boom,

00:58:38.640 | your adaptive immune system churns those antibodies out

00:58:41.320 | and kills the virus.

00:58:42.360 | Now, as a final point about the immune system,

00:58:44.320 | I've been talking a lot today about cells traveling to

00:58:46.680 | and killing viruses and sending signals,

00:58:48.640 | "Eat me, help me," et cetera.

00:58:50.860 | It's important to understand that,

00:58:53.200 | while cells can migrate through the body,

00:58:55.160 | a lot of what we're talking about here

00:58:56.660 | is the movement of proteins through the vascular,

00:58:58.880 | through the blood system of the body,

00:59:01.060 | but there's another system that's very important

00:59:02.840 | for all of this that's collaborating

00:59:04.320 | with the vascular system, and that's the lymphatic system,

00:59:07.080 | and we don't have time to go into a whole lecture

00:59:09.000 | about the lymphatic system, but suffice to say,

00:59:11.580 | the lymphatic system can pull stuff from the blood,

00:59:15.840 | such as viruses, but also cells that have been beaten up

00:59:20.840 | or cells that have been eaten and are contained

00:59:24.000 | within other cells, such as macrophages,

00:59:25.880 | and it can do some filtering of those different cell types,

00:59:29.080 | and it can produce its own useful chemicals

00:59:30.840 | that then can be reintroduced to the bloodstream

00:59:33.160 | in order to help combat the infection.

00:59:35.440 | Now, this becomes very important when later we talk about

00:59:37.940 | how specific forms, intensities, and durations

00:59:41.160 | of exercise can increase the ability

00:59:44.280 | for your innate immune system to combat infections

00:59:47.680 | so that your adaptive immune system perhaps

00:59:49.540 | doesn't even have to get involved in the battle

00:59:51.280 | because your innate system handled it.

00:59:53.340 | There are data to show the exercise

00:59:54.840 | of sufficient intensity and duration,

00:59:56.920 | but not excessive intensity and duration,

01:00:00.240 | can recruit the lymphatic system and recruit

01:00:03.000 | or increase the activity of the innate immune system

01:00:05.860 | even in the absence of an infection,

01:00:07.840 | such that if you go to that party

01:00:09.560 | and you encounter that person with a cold or flu,

01:00:11.840 | you can defeat that cold or flu virus at the outset

01:00:14.680 | and never have to deal with making antibodies

01:00:16.460 | to that cold or flu virus at all.

01:00:18.280 | Okay, so now you have a fairly sophisticated

01:00:20.080 | biological understanding of what colds are,

01:00:22.720 | what flus are, and the way that your immune system works

01:00:26.000 | to fight off viruses like colds and flus.

01:00:28.720 | So with that in mind, I think now is the appropriate time

01:00:31.420 | to start talking about what the scientific

01:00:33.800 | peer-reviewed research says about how to allow

01:00:37.120 | your immune system to function at its best

01:00:39.620 | such that you can combat colds and flus.

01:00:41.940 | Meaning, if you are exposed to a cold or flu,

01:00:44.440 | that is if it breaches that physical barrier of your skin

01:00:47.040 | and the mucosal lining of your nose, your mouth,

01:00:49.600 | or it gets into your eyes,

01:00:50.960 | that you stand the greatest chance of defeating

01:00:53.440 | that cold or flu at the level of your innate immune system,

01:00:56.520 | such that your adaptive immune system

01:00:58.200 | never even has to respond to it

01:00:59.680 | by creating all those specific antibodies.

01:01:01.960 | Now, fortunately, there are a lot of different things

01:01:03.880 | we can do to improve the function of our immune system.

01:01:06.640 | In fact, I feel like any time the winter months roll around,

01:01:09.040 | we start to see the same list of things surface

01:01:11.700 | online and in the press.

01:01:13.080 | And I don't want to diminish these things.

01:01:14.640 | They are in fact the bedrock of maintaining

01:01:17.120 | and enhancing the function of your innate immune system.

01:01:20.140 | So what are those?

01:01:21.280 | Well, some of these will be pretty obvious,

01:01:23.260 | things like getting enough quality sleep each night.

01:01:26.800 | We know, for instance, that if you're sleep deprived,

01:01:29.560 | so especially if you stay up all night,

01:01:31.640 | but certainly even if you only get 50% or 75%

01:01:36.640 | of your sleep requirement,

01:01:37.920 | that your innate immune system is going to suffer.

01:01:39.960 | It's not going to be as effective

01:01:41.700 | at combating flus or colds.

01:01:44.480 | In addition to that, we know that exercise of specific type

01:01:48.820 | and specific duration and specific intensity

01:01:51.760 | can serve to bolster the innate immune system.

01:01:54.120 | And we'll talk about the specific exercise protocols

01:01:56.400 | that can best achieve that.

01:01:58.280 | We also hear, and it's absolutely true,

01:02:00.120 | that we need adequate nutrition.

01:02:02.280 | If we are in a caloric deficit, for instance,

01:02:04.600 | if we're trying to diet through the winter months,

01:02:06.240 | which many people try to do,

01:02:08.180 | that can place our innate immune system

01:02:10.240 | in a bit of a compromised state.

01:02:11.880 | That said, things like intermittent fasting

01:02:15.140 | or even longer duration fasts have been implicated,

01:02:18.820 | and here I really want to underscore implicated,

01:02:20.960 | in brief improvements in the function

01:02:24.240 | of the innate immune system.

01:02:25.780 | However, extended fasts or not eating enough calories

01:02:28.620 | to maintain body weight for many, many days in a row

01:02:31.560 | can actually compromise the function

01:02:33.760 | of the innate immune system.

01:02:35.140 | I'll go into this a bit deeper in a moment.

01:02:37.500 | And then of course, we hear about stress,

01:02:39.300 | that we're all supposed to regulate our levels of stress,

01:02:41.340 | not get too stressed.

01:02:42.780 | And here I have to put an asterisk next to those statements

01:02:45.860 | because yes, indeed, chronic stress,

01:02:48.500 | meaning stress that continues day after day after day,

01:02:51.380 | or even short periods of stress

01:02:53.820 | that impede our ability to sleep at night,

01:02:56.500 | can indeed reduce the functioning of our innate immune system.

01:03:00.020 | However, it's also clear that short bouts of stress,

01:03:03.860 | provided that they don't inhibit our ability

01:03:06.380 | to sleep that night,

01:03:07.480 | can actually enhance the function of the immune system.

01:03:10.220 | And this is something that I don't think

01:03:11.740 | is talked about enough.

01:03:13.200 | You know, we hear so often that quote unquote,

01:03:15.080 | "Cortisol is bad, it's a stress hormone."

01:03:17.260 | Listen, cortisol is fantastic,

01:03:19.760 | provided that it is elevated early in the day

01:03:22.900 | and not late in the day or evening.

01:03:25.520 | Also, cortisol does have thresholds

01:03:28.060 | beyond which if it's too high, can be bad for us.

01:03:30.720 | But it's also the case that if cortisol levels are too low,

01:03:33.940 | that's bad for us,

01:03:35.340 | and it's especially bad

01:03:36.520 | for the functioning of our immune system

01:03:38.000 | because glucocorticoids, of which cortisol is,

01:03:41.340 | have an important role in activating

01:03:43.580 | those natural killer cells of the innate immune system.

01:03:46.300 | They are one of the primary signals

01:03:48.140 | by which those interleukins,

01:03:49.480 | like interleukin-1 and interleukin-6,

01:03:51.700 | are deployed in our body.

01:03:53.320 | And so very often we'll hear stress increases inflammation,

01:03:56.820 | and indeed interleukin-1 and interleukin-6

01:03:59.560 | are pro-inflammatory.

01:04:00.940 | You might think, "Oh my goodness, I don't want that.

01:04:02.300 | I don't want cortisol.

01:04:03.120 | I don't want these interleukins elevated."

01:04:04.920 | But guess what?

01:04:05.760 | The inflammation response is also an important component

01:04:09.360 | of that innate immune system

01:04:11.360 | that allows us to combat infections.

01:04:13.560 | So in trying to keep our innate immune system tuned up,

01:04:16.360 | I realize that's not a biological statement, tuned up,

01:04:18.540 | but keep our immune system functioning at its best,

01:04:21.540 | we want inflammation available as a tool

01:04:24.700 | to combat infection.

01:04:25.700 | We want cortisol available as a way

01:04:29.200 | to activate that inflammation

01:04:30.660 | and other aspects of our immune system.

01:04:32.340 | We just don't want so much cortisol

01:04:34.660 | and so much inflammation that we can't sleep

01:04:37.500 | and that our gut microbiome suffers.

01:04:39.460 | And that brings me to the other component

01:04:41.220 | that's important for the basic functioning

01:04:43.480 | of your innate immune system

01:04:44.540 | so that you can be at your strongest

01:04:46.000 | when you inevitably encounter those cold and flu viruses.

01:04:49.300 | Why do I say inevitably?

01:04:50.620 | Look, if you exist in the world,

01:04:53.460 | that is, if you live on planet earth,

01:04:55.060 | you are going to be bombarded with different viruses

01:04:57.740 | and bacteria and funguses

01:04:59.540 | and all this stuff throughout your days.

01:05:00.980 | And yes, in those winter months,

01:05:02.380 | because people are spending more time indoors

01:05:04.300 | and they're touching each other and surfaces more,

01:05:06.980 | breathing on each other more,

01:05:08.100 | sneezing on each other more, and so on and so forth,

01:05:10.300 | there is more propagation of colds and flus.

01:05:13.180 | So if we take a step back and we ask,

01:05:14.780 | "How can I have my immune system as strong

01:05:17.300 | and ready as possible to combat cold and flu viruses?"

01:05:20.360 | We get to those basics.

01:05:21.500 | It's make sure you're getting enough quality sleep

01:05:24.340 | each night.

01:05:25.540 | How much is enough?

01:05:27.420 | However much you need in order to not feel sleepy

01:05:31.020 | during the day, except maybe the requirement

01:05:32.980 | for a short nap of anywhere from 10 to 30 minutes.

01:05:35.600 | Not everyone requires that, but that's perfectly normal

01:05:37.620 | to have an afternoon dip in energy

01:05:39.500 | that can be restored with a short nap

01:05:42.660 | or non-sleep deep rest.

01:05:43.820 | We'll provide links to non-sleep deep rest

01:05:46.020 | and other tools in the show note captions

01:05:47.940 | that are zero cost tools to allow you to recover your energy.

01:05:51.120 | Some people just simply take a nap and that sort of thing.

01:05:53.500 | If you want tools for improving your sleep

01:05:56.560 | and making sure that you're getting enough quality sleep

01:05:58.480 | each night, we will also provide a link

01:06:00.520 | to our zero cost sleep toolkit

01:06:02.320 | that details that in PDF form.

01:06:04.140 | It just lists out the things that you can do or take

01:06:06.400 | if that's your choice and so on and so forth.

01:06:08.640 | And of course we've done episodes on quality nutrition

01:06:11.240 | and what that means.

01:06:12.060 | We've done episodes on stress and how to combat stress,

01:06:15.320 | and we've done episodes on the so-called gut microbiome.

01:06:18.860 | But right now, I just want to mention

01:06:20.900 | that the gut microbiome,

01:06:22.200 | which are the trillions of little micro bacteria

01:06:25.660 | that interact heavily with the immune system

01:06:27.400 | and help support the immune system,

01:06:28.520 | you want to keep the gut microbiome healthy.

01:06:30.440 | So you'll notice that we include some tools

01:06:32.140 | related to the gut microbiome here in a moment.

01:06:34.540 | And this is very important.

01:06:36.540 | Keep in mind that the microbiome

01:06:38.460 | doesn't just exist in the gut.

01:06:40.500 | So often these days we hear about the gut microbiome

01:06:42.860 | and I'm oh so happy that the gut microbiome

01:06:44.900 | is getting the attention that it deserves

01:06:46.360 | in the context of mental health,

01:06:47.500 | physical health and performance.

01:06:48.940 | But we can't forget that the microbiome also exists

01:06:53.040 | on the surface of the eyes and in the nasal passages.

01:06:56.740 | And indeed the microbiome that's specific

01:06:59.220 | to the nasal passages, as I mentioned before,

01:07:01.700 | is very different from the microbiome

01:07:04.400 | that exists within the mouth.

01:07:06.100 | And the microbiome that exists within the mucosa

01:07:08.300 | of the nasal passages seems to be the most effective

01:07:11.620 | at combating any viruses that we encounter,

01:07:14.300 | especially cold and flu viruses.

01:07:16.340 | So while ideally you would never encounter

01:07:18.300 | a cold or flu virus, we know that if the cold or flu viruses

01:07:21.060 | go in through the nasal passages,

01:07:22.960 | you stand the greatest chance of combating

01:07:25.300 | that particular cold or flu.

01:07:27.500 | So what does that mean?

01:07:29.420 | This is where I get to make a strong push

01:07:31.100 | for being a nasal breather.

01:07:33.860 | Certainly in sleep, you want to be a nasal breather,

01:07:36.780 | but also throughout the day, unless you're speaking

01:07:39.100 | or unless you're exercising hard enough

01:07:40.700 | that you need to breathe through your mouth

01:07:42.700 | or unless you're eating, being a nasal breather

01:07:46.140 | is known to provide the right milieu, the right environment

01:07:50.000 | to keep that nasal microbiome at its healthiest

01:07:52.800 | and to promote the diversity of microbiota

01:07:54.980 | in the nasal passages that can best protect you

01:07:57.340 | against colds and flus.

01:07:59.740 | And there are a growing number of studies

01:08:00.920 | that point to this fact.

01:08:02.440 | I'll provide a link to one that I like very much,

01:08:04.340 | which is entitled "Alterations in Oral Nasal Pharyngeal

01:08:07.100 | "Microbiota and Salivary Proteins

01:08:08.840 | "in Mouth-Breathing Children."

01:08:10.020 | This is but one study pointing to the fact

01:08:12.780 | that being a nasal breather is a good thing.

01:08:16.620 | Mouth-breathing children and mouth-breathing adults,

01:08:19.180 | meaning children and adults that default to mouth-breathing

01:08:22.620 | tend to get more infections of the upper respiratory tract,

01:08:26.140 | including colds and flus.

01:08:27.560 | Consciously focusing on nasal breathing

01:08:29.340 | is one of the best things that we can all do

01:08:31.640 | to combat any colds or flus that we might encounter.

01:08:35.580 | So earlier we talked about trying to avoid

01:08:37.820 | touching your eyes, at least without washing your hands first

01:08:41.000 | or sanitizing your hands first after you meet somebody,

01:08:44.040 | keeping in mind that most people do that unconsciously.

01:08:47.540 | Here we are also saying when you enter a room,

01:08:50.300 | you're hanging out with people,

01:08:51.860 | maybe you're waiting for public transportation

01:08:53.500 | or you're at work or walking down the hallway,

01:08:55.940 | unless you are exercising hard, unless you are talking,

01:09:00.940 | try to focus on being a nasal breather.

01:09:03.000 | There are a bunch of other reasons

01:09:04.120 | to be a nasal breather as well,

01:09:05.600 | but this is one of the primary ones.

01:09:07.040 | And I'll provide a link to another reference,

01:09:09.180 | which is the book "Jaws" by my colleagues at Stanford,

01:09:12.020 | which talks about nasal breathing

01:09:13.820 | and the importance of nasal breathing,

01:09:15.420 | but also the degree to which children and adults

01:09:18.940 | open themselves up to increased levels of viral infections,

01:09:23.500 | as well as bacterial infections,

01:09:24.780 | but viral infections in particular,

01:09:26.680 | when they rely on mouth-breathing

01:09:28.900 | and the incredible benefits of doing this very simple,

01:09:31.700 | zero cost thing of whenever you can consciously remember to

01:09:36.680 | breathing through your nose,

01:09:38.300 | as opposed to breathing through your mouth.

01:09:40.940 | And just as an additional point about nasal breathing,

01:09:42.940 | because I can't resist telling you this,

01:09:44.140 | I just think it's so cool, such an interesting adaptation.

01:09:47.340 | When we breathe through our nose,

01:09:50.340 | we heat the air in a way that's very different

01:09:53.420 | from the way we heat the air when we mouth breathe.

01:09:55.880 | And by heating the air that's coming into the nasal passages,

01:09:58.780 | it shifts the probability that cold or flu viruses

01:10:02.460 | will successfully embed in the mucosal lining

01:10:05.540 | and infect the underlying cells

01:10:07.240 | and get into the other cells and tissues of our body.

01:10:09.980 | So this whole thing about nasal breathing

01:10:12.960 | is important and effective at the level

01:10:15.240 | of temperature regulation of the milieu within the nose,

01:10:18.840 | and therefore the viruses that end up in the nose,

01:10:20.960 | as well as the mucosal lining,

01:10:22.240 | the chemicals made by the mucosal lining.

01:10:24.120 | And again, the nose is a very different place

01:10:27.840 | than the mouth.

01:10:28.680 | In fact, I'll provide a link to yet another paper,

01:10:31.420 | which is entitled Human Nasal Microbiota.

01:10:35.180 | It's a really interesting paper.

01:10:36.360 | It's actually an interview with a scientist

01:10:37.940 | who's expert in the nasal microbiome,

01:10:41.320 | talking about how this structure within our nose

01:10:44.540 | really is the primary defense site

01:10:47.120 | by which we destroy potentially incoming viruses.

01:10:50.360 | So if it sounds overly simple,

01:10:52.360 | just breathe through your nose.

01:10:54.020 | It is very simple, but it's also very effective.

01:10:57.380 | Now it's also clearly the case

01:10:58.760 | that keeping your gut microbiome is advantageous

01:11:01.360 | for keeping your innate immune system

01:11:03.440 | at its most robust level of functioning.

01:11:06.220 | And I should mention that your gut microbiome

01:11:08.540 | isn't just about your stomach.

01:11:10.440 | You know, we hear the word gut and we think stomach,

01:11:12.460 | but it's actually the entire length of your digestive tract

01:11:16.640 | from your mouth out the other end.

01:11:19.180 | And different microbiota exist at different locations

01:11:22.160 | along that tract of mucosa.

01:11:25.700 | And there are a couple of things that one can do

01:11:27.500 | in order to make sure that the gut microbiome

01:11:29.580 | is best supported along that entire length.

01:11:32.380 | The first one is that,

01:11:34.960 | and this was covered on the episode

01:11:36.280 | that we did with my colleague, Justin Sonnenberg,

01:11:38.780 | who is a world expert in the gut microbiome.

01:11:41.240 | And that is to consume anywhere from two to four servings

01:11:43.960 | of low sugar fermented foods per day.

01:11:46.520 | So things like sauerkraut, things like kimchi,

01:11:49.480 | things like kefir, things like kombucha.

01:11:52.600 | It can be a little bit of work

01:11:53.680 | to figure out which of these you like

01:11:56.200 | and which ones you're willing to consume on a regular basis.

01:11:59.160 | But it's very clear that the brine,

01:12:00.920 | you know, that kind of a salty solution

01:12:03.780 | around the sauerkraut, and by the way,

01:12:05.260 | when I say sauerkraut, what we're talking about here

01:12:07.240 | is the type that has to be refrigerated.

01:12:08.980 | It contains what are called live cultures

01:12:11.880 | as opposed to the sauerkraut that can exist

01:12:13.660 | in the non-refrigerated portion of the store.

01:12:16.220 | Or pickles that also have that brine

01:12:19.340 | and that have to be kept in the refrigerator

01:12:21.220 | even before they're opened.

01:12:22.940 | And of course, things like yogurt,

01:12:24.500 | which have active live cultures.

01:12:27.560 | Those are the sorts of things that are going to best support

01:12:29.840 | the diversity of microbiota

01:12:31.420 | along the entire length of the gut microbiome,

01:12:34.920 | such that your gut microbiome can do its job

01:12:37.440 | in supporting your nervous system.

01:12:39.300 | But here, especially in the context of today's discussion,

01:12:42.640 | your immune system.

01:12:44.840 | Now, the low sugar component

01:12:48.040 | of low sugar fermented foods is important

01:12:50.000 | because what we know is that if you're consuming yogurts

01:12:53.060 | with a lot of sugar, or you're consuming kombucha

01:12:55.240 | with high levels of sugar, or you're consuming pickles

01:12:58.140 | or sauerkraut that have a lot of sugar in them,

01:13:00.740 | you're probably going to start to create some other issues

01:13:02.840 | related to the sugar.

01:13:03.720 | What you're really looking for

01:13:04.560 | are these low sugar fermented foods.

01:13:06.340 | And they can be a little bit tricky to seek out in the store,

01:13:08.540 | but they're usually there.

01:13:10.140 | And once you identify the ones that you like,

01:13:11.660 | you should really aim to get two to four servings

01:13:13.560 | of those per day.

01:13:14.780 | You can also consume a prebiotic or probiotic

01:13:16.980 | in the form of capsule form.

01:13:18.660 | Things like AG1 athletic greens

01:13:20.380 | also contain prebiotic, probiotic,

01:13:23.380 | but it's very clear that consuming two to four servings

01:13:27.560 | of low sugar fermented foods per day

01:13:29.420 | is among the best ways to promote health

01:13:31.640 | of the gut microbiome.

01:13:32.740 | And that the gut microbiome is so, so important

01:13:35.660 | for keeping the innate immune system thriving,

01:13:38.560 | such that it can combat the colds or flus

01:13:40.440 | that are trying to bombard your system.

01:13:42.380 | Now there's another tool that you can use

01:13:43.900 | to enhance your gut microbiome.

01:13:45.620 | I have to warn you,

01:13:46.460 | this one might make a few of you cringe a little bit,

01:13:49.420 | but this is one that I actually started doing

01:13:51.020 | about four months ago.

01:13:52.960 | It's an interesting one.

01:13:54.100 | It kind of dates back to some older quote unquote

01:13:56.700 | traditional medicine practices,

01:13:58.280 | but it makes really good logical sense.

01:14:00.940 | To be fair,

01:14:01.780 | I'm not aware of any randomized control trial

01:14:03.700 | exploring the use of this protocol,

01:14:05.160 | but it's so simple and completely cost-free

01:14:07.460 | and it stands so strongly on the logic

01:14:09.900 | of how the gut and oral microbiome work

01:14:12.160 | that frankly I started doing it

01:14:13.680 | and whether or not it's placebo effect or not, I don't know,

01:14:16.780 | but I feel better and it's so easy to do

01:14:20.160 | and it stands to potentially improve the function

01:14:23.620 | of your gut microbiome enough

01:14:25.860 | that I figured I would at least share it with you

01:14:27.540 | and then you can decide.

01:14:28.860 | So what this protocol essentially consists of

01:14:30.820 | is before you go to sleep at night or in the morning,

01:14:33.520 | you pour yourself a little bit of water,

01:14:36.580 | whatever water you happen to consume,

01:14:37.920 | just clean, clear water.

01:14:39.780 | And then you take a sip of that water

01:14:41.380 | when you wake up in the morning

01:14:42.780 | and you swish it around in your mouth

01:14:44.620 | and then you swallow it.

01:14:47.540 | Now for those of you that are like, oh, gross,

01:14:50.180 | let's think about this.

01:14:51.120 | Is it really gross

01:14:52.740 | to swish a little bit of water around in your mouth

01:14:54.940 | and then swallow that water when you first wake up

01:14:57.300 | prior to brushing your teeth, of course?

01:14:59.300 | Well, it might seem gross to you,

01:15:01.500 | but throughout the night when you're sleeping,

01:15:03.660 | especially if you are a nasal breather while you sleep,

01:15:08.440 | the environment within your mouth

01:15:10.840 | is such that you're breeding a lot of bacteria.

01:15:13.180 | You are creating all those little microbacteria

01:15:16.340 | that potentially can inhabit your digestive tract

01:15:20.740 | and provide at least some of the substrate

01:15:23.100 | for the microbiota in your digestive tract to thrive.

01:15:26.460 | And if that seems gross to you, keep in mind,

01:15:27.980 | that's what having a healthy gut microbiome

01:15:30.380 | really is all about.

01:15:31.980 | So the protocol is very simple at zero cost.

01:15:34.320 | You take a swig of water, swish around and swallow it.

01:15:38.600 | Oddly, it doesn't taste bad.

01:15:41.220 | In fact, it'll just taste like swallowing.

01:15:44.140 | And in fact, it tastes like swallowing

01:15:46.020 | a little bit of water.

01:15:46.840 | It's not as if it tastes like bad breath

01:15:50.020 | or something like that.

01:15:51.180 | It's a very simple protocol that, again,

01:15:53.620 | no randomized control trials,

01:15:55.020 | but really stands on the logic of how the oral microbiome

01:15:57.940 | and the gut microbiome interact.

01:16:00.540 | And because what we're talking about here

01:16:01.940 | is supporting the function of your gut microbiome

01:16:04.260 | such that it supports the function

01:16:05.700 | of your innate immune system,

01:16:06.740 | such that you can avoid colds and flus.

01:16:08.780 | At least to me, it seems like a pretty low bar, yes.

01:16:12.420 | Okay, so to bolster your innate immune system,

01:16:14.600 | you want to get that quality sleep

01:16:16.220 | as often as you possibly can.

01:16:17.940 | You want to support the gut microbiome

01:16:19.620 | in the ways that we just described.

01:16:21.420 | What about exercise?

01:16:22.500 | We hear it all the time.

01:16:23.680 | Exercise is so good for us.

01:16:25.160 | It enhances the immune system and on and on.

01:16:28.140 | And listen, I'm a huge believer in exercise.

01:16:30.780 | I personally like to do three bouts

01:16:33.100 | of cardiovascular exercise per week,

01:16:35.420 | one long, one medium, one short.

01:16:37.140 | And I do three bouts of resistance training each week.

01:16:40.460 | All of that, and specifically what I do

01:16:42.500 | is available to you as a zero cross protocol

01:16:44.900 | in the form of a PDF.

01:16:46.220 | We have a link to that in the show note captions.

01:16:47.980 | I also have a whole episode about foundational fitness

01:16:50.580 | and so on and so on.

01:16:52.020 | The discussion we're going to have now

01:16:53.620 | is about what general forms of exercise

01:16:56.660 | actually do support the innate immune system.

01:16:59.280 | And, and this is really important,

01:17:01.420 | what forms of exercise actually deplete

01:17:04.080 | your innate immune system?

01:17:05.300 | This isn't talked about enough, I think.

01:17:07.900 | There are certain intensities and durations of exercise

01:17:11.060 | that make us more vulnerable to colds and flus.

01:17:14.300 | So we're going to discuss that.

01:17:15.580 | Before we do that, I want to just briefly touch

01:17:17.560 | into something that I hear a lot,

01:17:19.540 | which is the question,

01:17:21.000 | if I'm feeling a little bit rundown,

01:17:22.720 | should I exercise or not?

01:17:24.580 | And to be honest, there isn't a straightforward answer

01:17:26.580 | to that question.

01:17:27.660 | It's impossible for me or for you to know

01:17:30.600 | whether or not you were indeed exposed to a cold or flu

01:17:33.140 | and you're starting to combat it

01:17:34.400 | at the level of your innate immune system,

01:17:36.780 | or whether or not you're just feeling a little bit sluggish.

01:17:40.260 | However, what we do know is that if you are feeling malaise

01:17:44.440 | at the level of the body,

01:17:45.740 | like your body is feeling different,

01:17:47.660 | it's feeling heavier, you're feeling tired,

01:17:49.940 | you're feeling tired at a time of day

01:17:52.160 | that doesn't make sense,

01:17:53.600 | given your usual patterns of being tired.

01:17:55.600 | You're feeling tired in a way that doesn't make sense,

01:17:57.960 | given how much sleep you got the night before, right?

01:18:00.100 | I mean, here, what we're talking about

01:18:01.080 | is ruling out any possible life stress,

01:18:03.560 | or you were up too late,

01:18:04.700 | or you drank caffeine at the wrong time,

01:18:06.360 | or something like that.

01:18:07.620 | What we know is that if you're feeling that general malaise

01:18:10.100 | across your whole body,

01:18:12.080 | it is fairly likely that you're coming down with something

01:18:15.200 | and that your best response to that would be to go home,

01:18:18.880 | take a hot shower or bath,

01:18:20.040 | I'll explain why you would want to do that in a few minutes,

01:18:21.820 | and then get into bed early,

01:18:23.260 | and even if you can't fall asleep,

01:18:24.600 | to just be as still and as relaxed as possible.

01:18:28.760 | We know that if you push into bouts of intense activity,

01:18:33.020 | or even just push yourself to engage in activity

01:18:35.460 | when you're feeling run down at that sort of

01:18:37.040 | whole body level, maybe a little tickle in your throat,

01:18:39.800 | you are going to compromise

01:18:41.160 | the function of your innate immune system.

01:18:42.920 | And it's very likely that you're going to get

01:18:44.960 | more sick than you would otherwise.

01:18:47.080 | So here's my suggestion.

01:18:49.060 | If you're starting to feel run down

01:18:50.360 | at the level of whole body malaise,

01:18:51.720 | or you just don't feel right,

01:18:53.640 | you're best off taking a hot shower or bath

01:18:56.360 | and getting into bed,

01:18:57.200 | or just getting into bed and trying to rest

01:18:59.080 | and get as much sleep,

01:18:59.960 | probably even a little bit of extra sleep.

01:19:02.040 | And here's why.

01:19:03.600 | That whole body malaise,

01:19:04.760 | that extra fatigue that's not easily explained

01:19:07.520 | by other factors in your life,

01:19:09.220 | have to do with the fact that

01:19:11.480 | when your innate immune system is activated,

01:19:13.880 | meaning it's already combating a cold or flu,

01:19:16.700 | interleukin-1 and interleukin-6

01:19:19.760 | have a way of interacting with a particular brain area

01:19:22.500 | called the dorsal raphae nucleus,

01:19:24.180 | which is chock-a-block full of neurons

01:19:25.880 | that release serotonin.

01:19:27.120 | And serotonin from the dorsal raphae nucleus

01:19:29.600 | acts on specific regions of your hypothalamus,

01:19:32.280 | areas like the preoptic region,

01:19:34.080 | for those of you that want to know,

01:19:35.180 | and other areas of the hypothalamus

01:19:37.160 | that generate a state of sleepiness.

01:19:39.760 | In addition, when we are getting sick,

01:19:42.500 | our sleep patterns change.

01:19:44.040 | We feel like we need to sleep more,

01:19:45.520 | but we don't feel as rested from that sleep.

01:19:47.720 | And that has to do with the ways

01:19:48.960 | that serotonin interacts with some of the components

01:19:51.860 | of the brain circuitry involved in sleep

01:19:53.700 | that controls slow wave or deep sleep.

01:19:55.840 | And this is a whole discussion unto itself.

01:19:57.560 | I actually covered a lot of the mechanistic aspects

01:19:59.640 | of this business of immune-induced sleepiness

01:20:03.040 | and malaise associated with feeling sick

01:20:05.400 | in an episode about interactions

01:20:07.400 | between the neural and immune system

01:20:08.880 | that I will also provide a link to

01:20:10.600 | in the show note captions.

01:20:11.700 | But suffice to say,

01:20:12.540 | if you're feeling that whole body malaise,

01:20:13.920 | and especially if you also

01:20:14.760 | have a little bit of a throat tickle,

01:20:15.800 | you're just not feeling right for you,

01:20:18.000 | you're not accustomed to feeling that way

01:20:19.560 | at that time of day or night,

01:20:21.160 | well, then I encourage you to get rest

01:20:22.940 | because chances are you're already combating an infection.

01:20:26.120 | However, if you are out and about a lot

01:20:29.560 | during the winter months,

01:20:30.480 | or you're interacting with a lot of people

01:20:33.700 | by virtue of work or public transportation or whatever,

01:20:36.560 | the gym, et cetera, or you're a school teacher,

01:20:38.900 | maybe your kids are coming home with colds and flus,

01:20:41.600 | and you're not yet feeling that malaise,

01:20:44.280 | you're not feeling any throat tickle,

01:20:46.100 | you're not getting that kind of burning

01:20:48.860 | or tickle within your nasal passages when you breathe.

01:20:51.240 | We're all familiar with these things,

01:20:52.260 | the watering of the eyes

01:20:53.200 | that kind of precedes getting the full-blown cold or flu.

01:20:57.100 | Well, if you're not experiencing that stuff

01:20:59.200 | and you want to keep your innate immune system strong

01:21:01.700 | and able to combat off colds and flus,

01:21:03.700 | then we know that exercise can be an excellent way

01:21:07.300 | to increase the output of that innate immune system.

01:21:11.420 | What I mean by that is the appropriate intensity

01:21:13.640 | and duration of exercise can act as a stressor

01:21:16.940 | that promotes a bit of inflammation,

01:21:19.420 | yes, the release of cytokines,

01:21:21.640 | and a bit of activation of the innate immune system,

01:21:24.660 | including the production of more white blood cells,

01:21:26.600 | natural killer cells,

01:21:27.860 | such that you're sort of prompting the innate immune system

01:21:31.060 | to almost think that there's something to battle

01:21:33.220 | such that if you ever encounter an infection,

01:21:36.020 | you can defeat it right off the bat.

01:21:38.780 | So we're going to get granular here

01:21:40.140 | about what we mean by proper intensity

01:21:42.400 | and duration of exercise.

01:21:43.680 | There's a wonderful review that was published in 2019

01:21:46.540 | in the Journal of Sport and Health Science

01:21:48.820 | entitled "The Compelling Link Between Physical Activity

01:21:51.380 | and the Body's Defense System."

01:21:52.820 | And there's a lot to this review article,

01:21:54.560 | but I'll just highlight a few of the critical features

01:21:56.820 | that are going to directly relate to protocols

01:21:58.840 | that I think all of you are going to be interested in.

01:22:00.880 | First of all, we know that exercise

01:22:04.340 | that's of 60 minutes in duration or less,

01:22:09.220 | and that is intense, but not all out effort, okay?

01:22:13.060 | Here, we're not talking about

01:22:14.300 | percentage of single repetition max weight.

01:22:17.500 | Here, we're not talking about 70 to 85% of one's VO2 max.

01:22:22.040 | What we're talking about is you subjectively gauging

01:22:25.460 | what is a 10 out of 10 effort?

01:22:27.460 | Like you could not do any more.

01:22:28.980 | You could not contribute any more effort

01:22:31.300 | to that exercise bout.

01:22:32.740 | And that's true whether or not

01:22:33.660 | we're talking about resistance training exercise

01:22:35.180 | or cardiovascular exercise like running or rowing

01:22:37.740 | or things of that sort.

01:22:39.080 | What we know is that if you do that sort of exercise

01:22:41.580 | for about 60 minutes or less,

01:22:43.840 | you promote the exchange of components

01:22:47.080 | between the blood and the lymphatic system

01:22:49.700 | that increase the circulation of those cells and chemicals

01:22:54.620 | within the innate immune system,

01:22:56.000 | such that not just during exercise,

01:22:58.220 | but for many, many hours afterwards,

01:22:59.960 | maybe even as much as 24 hours afterwards,

01:23:02.740 | your innate immune system level of baseline activity

01:23:05.940 | is ramped up, allowing you to better combat infections

01:23:09.600 | such as colds and flus.

01:23:11.540 | Okay, so this is an incentive for getting regular exercise

01:23:14.840 | of 60 minutes or less per day,

01:23:17.040 | making it of sufficient intensity

01:23:21.000 | for your innate immune system

01:23:23.040 | to deploy more of those chemicals

01:23:25.000 | and for your lymphatic and blood circulation

01:23:27.800 | to increase their exchange of materials

01:23:31.000 | enough that your innate immune system is bolstered.

01:23:33.680 | However, it is absolutely not the case

01:23:35.560 | that more is better.

01:23:36.880 | In fact, it's probably the case that less is better.

01:23:40.400 | Here's what we know for sure.

01:23:41.440 | And this review covers sort of the extreme

01:23:43.680 | of these examples.

01:23:44.520 | But for instance, people that do bouts of walking each day

01:23:49.060 | for about 60 minutes, brisk walking,

01:23:51.540 | experience increased T cell function.

01:23:54.460 | So that's an immune cell that goes out

01:23:56.100 | and combats cold and flu viruses

01:23:58.460 | and natural killer cell activity.

01:24:00.160 | So those increase.

01:24:01.540 | Increased macrophage function.

01:24:02.840 | You are now familiar with these cells.

01:24:04.160 | If you don't know exactly what they do,

01:24:05.520 | just keep in mind that you heard about these

01:24:06.880 | in the context of what the innate immune system does

01:24:09.600 | to go out and fight colds and flus.

01:24:12.140 | Cytokines increase, but not dramatically, okay?

01:24:17.320 | So this is a mild inflammation response.

01:24:19.300 | Stress hormones such as cortisol, epinephrine,

01:24:22.040 | norepinephrine, also called adrenaline and noradrenaline.

01:24:25.120 | Those are deployed as well.

01:24:26.160 | So 60 minutes or less of this moderate

01:24:30.600 | to high intensity exercise

01:24:32.580 | creates this mild stress response

01:24:34.120 | and an increase in the function of the innate immune system.

01:24:37.560 | However, people that run a marathon,

01:24:40.120 | and as I recall, a marathon is 26.2 miles,

01:24:43.120 | if I'm not mistaken,

01:24:44.440 | they experience a very different pattern of immune response

01:24:50.120 | to that long bout of exercise.

01:24:52.440 | So here we're comparing one hour of exercise to three hours.

01:24:56.200 | Is that what it takes to run a marathon?

01:24:57.560 | I have some friends that are marathoners.

01:24:58.720 | I'm guessing about three, maybe four hours

01:25:00.360 | if you're really slow,

01:25:01.640 | but somewhere between, I don't know,

01:25:03.440 | two and a half and three hours

01:25:04.760 | if you're trained up and you're doing it

01:25:06.760 | and you're doing them regularly.

01:25:08.080 | Well, here's the point.

01:25:10.120 | People who just ran a marathon

01:25:12.200 | and people who have been training for a marathon

01:25:14.160 | and are approaching that marathon

01:25:15.720 | are severely immune compromised.

01:25:18.500 | The levels of their T cell function

01:25:21.300 | are way below baseline,

01:25:23.360 | meaning their innate immune system

01:25:24.480 | is not functioning nearly as well as it would

01:25:26.540 | if they were to not exercise at all.

01:25:28.560 | Their natural killer cell activity

01:25:29.920 | is also greatly diminished.

01:25:31.360 | These are huge, huge reductions in these cells

01:25:34.080 | that is in the function of the innate immune system

01:25:35.920 | and their stress hormones

01:25:37.440 | and their inflammatory molecules

01:25:39.240 | such as cytokines circulating in their blood

01:25:42.100 | are extremely high.

01:25:44.140 | Now again, we're representing opposite ends of the spectrum

01:25:46.640 | here with one hour or less of exercise daily

01:25:50.140 | versus 26.2 mile marathon exercise

01:25:53.840 | or half marathons as the case may be.

01:25:55.640 | And let me be very direct.

01:25:56.940 | I'm not discouraging people from running

01:25:59.200 | or training for marathons or half marathons.

01:26:01.120 | I think that's great.

01:26:01.960 | Just understand what you're doing to your immune system

01:26:03.680 | when you do that and take the necessary precautions.

01:26:06.040 | But I think most people listening to this

01:26:08.080 | are trying to think about ways

01:26:09.140 | that they can avoid getting colds and flus.

01:26:11.200 | And certainly running marathons

01:26:12.800 | is not going to be the way to do that.

01:26:14.520 | Quite the contrary.

01:26:15.360 | The way to do that is in addition to the other things

01:26:17.560 | we've been talking about to get regular exercise,

01:26:20.080 | maybe not every single day.

01:26:21.640 | I'm actually a fan of taking one day per week

01:26:23.720 | completely off from exercise.

01:26:25.760 | Usually on that day, I'll do some sauna and cold

01:26:27.700 | if I have it available to me.

01:26:29.120 | But the point is this,

01:26:31.700 | you don't have to exercise for an hour a day

01:26:34.600 | in order to get this improvement

01:26:36.080 | in the innate immune response.

01:26:37.920 | Data show that you can get this improvement

01:26:40.360 | in innate immune response

01:26:42.100 | with as little as 20 minutes per day

01:26:44.700 | and probably even as little as 12 minutes per day.

01:26:47.280 | However, if you're going to try and accomplish this increase

01:26:49.820 | in the innate immune system function or output

01:26:53.040 | with a shorter bout of exercise, such as 12 minutes,

01:26:55.800 | it better be 12 minutes of very high intensity training.

01:26:58.440 | In fact, that's what lands on my, for me, it's Friday,

01:27:01.020 | but it doesn't really matter which day of the week.

01:27:02.640 | There's one day of the week where I do a very short bout

01:27:05.040 | of cardiovascular exercise, but I'm sprinting hard

01:27:07.880 | for anywhere from 20 seconds to a minute.

01:27:09.780 | And then I'm taking a brief period of rest

01:27:11.160 | and then repeating that for a total of 12 minutes.

01:27:14.060 | Now, some people hear,

01:27:16.040 | oh, only 12 minutes of exercise required.

01:27:18.200 | And they default to 12 minutes every single time they train.

01:27:20.840 | I don't think that's a good idea.

01:27:21.880 | I think that we can take the law of averages here

01:27:24.520 | and say the following.

01:27:26.000 | I do believe everyone should do a combination

01:27:27.700 | of cardiovascular training and resistance training.

01:27:30.580 | Perhaps, I think in general, not on the same days,

01:27:33.560 | but if you're going to do that

01:27:35.400 | and you want to maintain healthy immune system function,

01:27:38.240 | my suggestion, what I do is unless it's the long bout

01:27:41.620 | of cardiovascular training that I do once a week

01:27:43.760 | and long for me means 60 to 90 minutes

01:27:46.380 | and sometimes longer if it's a hike,

01:27:48.600 | which certainly doesn't require that much intensity,

01:27:51.580 | I suggest warming up for about five to 10 minutes

01:27:56.640 | and then limiting your total workout duration

01:27:58.620 | to about 50 minutes, maybe 60 minutes

01:28:01.300 | if that's what's required to complete what you need to do

01:28:03.580 | in order to keep with your exercise goals.

01:28:06.340 | But to be very careful about exceeding 75 minutes

01:28:10.100 | of exercise in any one single exercise bout.

01:28:13.060 | And if you remember back to the beginning of the episode,

01:28:14.920 | when I said that I track what I do on a day-to-day basis,

01:28:18.400 | and I don't do it in a very detailed way,

01:28:20.560 | but I do take note of when I've gotten a bad flu or cold,

01:28:24.280 | I can tell you that in almost every single case

01:28:27.360 | where I've gotten a bad flu or cold,

01:28:28.820 | there are two things that have proceeded

01:28:31.580 | that bad flu or cold.

01:28:32.920 | One is sleep deprivation.

01:28:35.640 | Typically it would be nights where I got two hours of sleep

01:28:39.880 | or less for more than one night, okay?

01:28:43.040 | The second thing is any time that I really pushed it

01:28:46.720 | with exercise and went all out and I went for 75 minutes

01:28:50.880 | and then I continued to 90 minutes

01:28:52.600 | and then maybe later that day, because somebody invited me

01:28:55.040 | on a run or something like that,

01:28:56.220 | I also did that second run or that second workout

01:28:59.480 | of some kind, could be running in the morning

01:29:00.880 | and weight training in the afternoon.

01:29:02.600 | Some people can do that kind of training

01:29:04.560 | on a regular basis even and not get sick.

01:29:07.100 | I am not such a person.

01:29:09.600 | I've managed to maintain fairly consistent fitness output,

01:29:12.840 | meaning the three cardiovascular

01:29:14.160 | and the three weight training sessions per week

01:29:16.020 | for more than several decades now.

01:29:17.480 | And part of the reason I think I've been able to do that

01:29:19.300 | is because I don't ever push too hard for too long

01:29:22.740 | within a given workout.

01:29:24.360 | So this is really a call for moderation

01:29:26.200 | in terms of the duration and intensity

01:29:27.860 | of the exercise that you're doing,

01:29:29.340 | but we're not talking about really being laid back.

01:29:32.340 | We're not talking about easy workouts.

01:29:34.020 | What we're talking about is an hour or less

01:29:35.780 | of moderate intensity to high intensity exercise,

01:29:38.500 | depending on the duration of that exercise,

01:29:40.500 | and keeping in mind that when you're doing that,

01:29:42.700 | you are activating that innate immune system.

01:29:45.220 | You're literally creating an immune response.

01:29:48.040 | You're increasing inflammation.

01:29:49.220 | You're increasing those cytokines.

01:29:50.980 | You're increasing stress hormones.

01:29:53.060 | We have to start to think about exercise for what it is,

01:29:55.520 | which is a form of stress that induces adaptations.

01:29:58.260 | Dr. Andy Galpin talked a lot about this

01:30:00.300 | in the series that he did on exercise physiology.

01:30:03.140 | It's an excellent series that covers everything

01:30:05.280 | from strength to hypertrophy to speed to endurance,

01:30:07.700 | nutrition, supplementation.

01:30:09.240 | You can find all that at HubermanLab.com very easily.

01:30:11.940 | Exercise is a very potent tool.

01:30:17.300 | We know that, we know that in the context

01:30:19.140 | of changing aesthetics, like body mass composition,

01:30:21.820 | increasing muscle, reducing fat.

01:30:23.240 | We know that in the context of reducing resting heart rate,

01:30:25.600 | reducing resting blood pressure.

01:30:27.620 | We know that in the context

01:30:28.860 | of all these other health metrics.

01:30:30.460 | Here, we're talking about using exercise

01:30:32.680 | as a very potent tool to increase the function

01:30:35.560 | of the innate immune system to keep you healthy,

01:30:37.740 | not just through the winter months, but around the year,

01:30:41.000 | and especially if you're getting less sleep.

01:30:44.280 | If you're interacting with kids or adults

01:30:46.340 | that are carrying infections home from school

01:30:48.160 | or work on a regular basis,

01:30:49.240 | or maybe you even work in an environment

01:30:50.900 | like a hospital or a clinic

01:30:52.460 | where you're regularly interacting with patients

01:30:54.240 | that have these issues.

01:30:55.580 | One thing that I often get asked is,

01:30:57.220 | if I am sleep deprived, should I exercise?

01:30:59.460 | And that's a little bit of a tricky one.

01:31:01.900 | My initial response for many years was, no, no.

01:31:05.460 | If you're sleep deprived, you're better off not exercising.

01:31:09.060 | However, I now need to qualify that answer

01:31:11.000 | because there are data showing that

01:31:12.860 | if you're sleep deprived and you exercise,

01:31:16.180 | especially if you exercise early in the day

01:31:18.720 | and it doesn't disrupt your sleep schedule,

01:31:20.580 | so it's not making you go to sleep

01:31:21.980 | even later the next night,

01:31:23.920 | that it actually can cause some adjustments

01:31:25.940 | in the function of your immune system

01:31:28.000 | and in the way that you regulate your blood sugar

01:31:29.960 | that offset some of the negative effects

01:31:32.040 | of sleep deprivation.

01:31:33.120 | That said, you should never ever compromise

01:31:36.460 | the amount of sleep you could get

01:31:38.240 | in order to get exercise such that you run yourself down.

01:31:40.740 | So what I'm really saying here

01:31:41.580 | is if you get one bad night's sleep,

01:31:42.940 | should you skip your workout and you feel like,

01:31:45.060 | ah, you know, I'm not feeling sick

01:31:46.920 | and should I work out or should I go back to sleep?

01:31:49.940 | Probably going back to sleep's the better idea,

01:31:51.780 | but if you don't have the option to go back to sleep

01:31:53.420 | for whatever reason, you can't fall back to sleep,

01:31:55.340 | then you would be wise to do a bout of exercise,

01:31:58.640 | but I would suggest reducing the intensity and duration

01:32:01.340 | of that exercise by about 25%, maybe even 50%.

01:32:05.060 | And that should allow you to offset

01:32:06.720 | any of the negative effects of sleep deprivation

01:32:08.620 | for that one night.

01:32:09.560 | Keep in mind, exercise is not a replacement for sleep.

01:32:13.140 | And then to allow you to get to sleep

01:32:15.560 | at the appropriate time later that night

01:32:17.060 | and back onto a regular schedule,

01:32:18.460 | keeping your innate immune system tuned up

01:32:20.420 | and ready to combat any colds or flus.

01:32:23.220 | Now, one more point about exercise,

01:32:24.780 | and here we're also going to dovetail in

01:32:26.620 | an important point about nutrition.

01:32:28.720 | In the review that I mentioned a few moments ago,

01:32:32.020 | they cover some of the data from studies

01:32:34.280 | exploring the post-exercise stress response.

01:32:37.700 | So this is the post-exercise induced increase

01:32:40.700 | in things like cortisol, those natural killer cells,

01:32:44.180 | the production of white blood cells, and so on.

01:32:46.580 | It's very clear that if you are in a state

01:32:50.460 | of chronic stress because you're exercising a lot

01:32:53.380 | and or because you're not sleeping enough,

01:32:55.440 | or for whatever reason, maybe you have a lot of life stress,

01:32:58.180 | it's very clear that ingesting carbohydrates

01:33:01.480 | after exercise can help attenuate some of the inflammation

01:33:05.180 | that exercise induces.

01:33:06.640 | When we talk about carbohydrates,

01:33:08.780 | we're talking about rice, oatmeal, pasta,

01:33:11.480 | those sorts of things, so-called complex carbohydrates.

01:33:14.820 | And fruit post-exercise has been shown to attenuate,

01:33:18.120 | to reduce some of the markers of inflammation

01:33:21.920 | by about 30 to 40%, when contrasted with water only intake,

01:33:26.920 | especially if you're training fasted.

01:33:28.920 | So for those of you like me

01:33:30.100 | that like to wake up in the morning and just drink fluids,

01:33:32.700 | for me, it's water, yerba mate, coffee.

01:33:35.560 | And by the way, I've said before

01:33:37.500 | that people should delay their caffeine intake 90 minutes

01:33:40.300 | if and only if they're experiencing an afternoon crash,

01:33:42.600 | but that if you are exercising first thing in the morning,

01:33:46.140 | it's perfectly fine to ingest your caffeine right away.

01:33:48.300 | So that gives you an increase in energy for that exercise.

01:33:51.580 | That's certainly what I do on days that I exercise.

01:33:54.140 | But if you fast and then you're drinking caffeine

01:33:56.540 | and then you're exercising,

01:33:57.640 | and that exercise goes longer than 60 minutes,

01:34:00.540 | certainly if it goes longer than 75 minutes,

01:34:02.820 | you would do well to ingest some complex carbohydrates,

01:34:05.620 | maybe also some fruit,

01:34:07.500 | perhaps not immediately after exercise,

01:34:09.220 | but within the 45 minutes or so or hour or so after exercise

01:34:12.780 | so that you're not ramping up those inflammatory molecules

01:34:15.780 | and leaving them ramped up for many hours

01:34:18.860 | into the morning and throughout the day.

01:34:20.700 | Because of course this episode

01:34:22.060 | is not about exercise and nutrition,

01:34:23.980 | but here we're talking about the role

01:34:25.500 | that exercise and nutrition play

01:34:27.420 | in helping us combat colds and flus

01:34:28.940 | by increasing the function of that innate immune system.

01:34:31.780 | And the reasons why carbohydrates can have this effect

01:34:34.700 | on cortisol, et cetera,

01:34:35.660 | is an interesting and important discussion into itself.

01:34:38.220 | We'll leave it for another episode, but keep that in mind.

01:34:40.780 | Also, I don't know about you,

01:34:41.820 | but a nice bowl of oatmeal, some fruit,

01:34:43.340 | and a protein drink or some eggs

01:34:44.700 | after an hour or so of exercise in the morning

01:34:48.140 | when I haven't eaten anything since the night before,

01:34:49.820 | it tastes really, really good.

01:34:51.860 | So continuing with the theme of things that we can do

01:34:54.660 | at the level of behaviors

01:34:56.180 | to improve the function of our innate immune system

01:34:58.320 | and combat colds and flus,

01:35:00.180 | perhaps even prevent us from getting colds and flus at all,

01:35:03.900 | but certainly help combat them

01:35:05.540 | if they've initially made their way into our system,

01:35:07.720 | but we haven't developed full-blown symptoms

01:35:09.600 | and we want to prevent those full-blown symptoms,

01:35:12.380 | is the use of deliberate heat exposure, in particular, sauna.

01:35:16.860 | There's a nice study on this

01:35:17.960 | that was published very recently, 2023.

01:35:21.100 | The title of the study is

01:35:22.200 | The Effects of a Single and Series of Finnish Sauna Sessions

01:35:25.860 | on the Immune System Response and Heat Shock Protein

01:35:28.340 | 70 Levels in Trained and Untrained Men.

01:35:30.800 | It's a very interesting study.

01:35:31.980 | They compared athletically trained

01:35:33.780 | and non-athletically trained men.

01:35:35.940 | As most of you probably know,

01:35:36.980 | when you get into a hot sauna, heart rate increases,

01:35:39.920 | there's vasodilation,

01:35:41.420 | there's the increase in the release of heat shock proteins,

01:35:44.300 | there's the increase in things like dynorphin,

01:35:47.260 | which if it's sufficiently hot,

01:35:49.660 | are increased to levels

01:35:50.740 | that make us feel kind of agitated and not so good.

01:35:53.260 | We have to actively calm ourselves in the sauna,

01:35:55.860 | so we're not talking about an easy cruise

01:35:57.420 | at 150 degrees Fahrenheit.

01:35:58.920 | We're talking about getting up into the 180 degree

01:36:02.240 | Fahrenheit or 210 degree Fahrenheit range,

01:36:05.560 | maybe even higher if you're heat adapted.

01:36:08.100 | And the dynorphin makes you feel lousy in the short term,

01:36:12.200 | but that it upregulates

01:36:13.160 | a bunch of different biological mechanisms

01:36:14.980 | that give you kind of low level euphoria

01:36:17.500 | and actually the capacity to experience

01:36:20.380 | more feelings of wellbeing from the endorphins

01:36:23.520 | that you make after you get out of the sauna.

01:36:25.400 | This is oh so important to understand

01:36:27.180 | whether or not we're talking about exercise

01:36:28.380 | or deliberate cold exposure, deliberate heat exposure.

01:36:30.680 | What happens during the heat exposure,

01:36:33.460 | cold exposure exercise is more often than not,

01:36:37.100 | just the trigger for the long-term adaptation

01:36:40.080 | that we're seeking.

01:36:40.980 | Just like exercise increases your heart rate

01:36:43.300 | and blood pressure,

01:36:44.520 | but then leads to reductions in resting heart rate

01:36:46.760 | and blood pressure and so on and so forth.

01:36:48.380 | This study is interesting

01:36:49.260 | and there are a lot of different takeaways from this study

01:36:51.080 | because they compare these two different populations.

01:36:54.080 | I'll just give you the top contour

01:36:56.540 | of what the protocol entailed.

01:36:57.740 | There were 10 sauna sessions.

01:36:59.140 | Each of those sauna sessions

01:37:00.880 | were three rounds of 15 minutes of sauna.

01:37:04.620 | So one session meant going into the sauna.

01:37:08.100 | The sauna was of a given temperature,

01:37:10.140 | but I think for most people,

01:37:11.160 | what's going to work in terms of what parallels this study

01:37:13.580 | is going to be somewhere between 176

01:37:15.820 | and 210 degrees Fahrenheit,

01:37:17.180 | depending on how heat adapted you are.

01:37:18.820 | Always be safe, don't do this if you're pregnant,

01:37:21.140 | don't do this if you're a child, et cetera.

01:37:24.060 | So they're doing three rounds of 15 minutes each

01:37:26.600 | separated by two minutes.

01:37:28.080 | During that two minutes,

01:37:28.920 | they take a cool shower where they cool off in some way.

01:37:32.180 | They're not going into a cold plunge,

01:37:33.580 | but they're cooling off with a cool shower.

01:37:36.580 | And they're doing that three times, that's one session.

01:37:39.400 | They do 10 sessions.

01:37:42.260 | Those sauna sessions were spaced apart

01:37:44.220 | by at least a few days and the entire experiment,

01:37:47.860 | meaning all 10 sessions were completed

01:37:49.860 | within a three week period.

01:37:51.280 | And then a bunch of things were measured,

01:37:52.560 | like the amount of white blood cells

01:37:54.940 | and immune cells that were deployed after the first session

01:37:58.100 | versus the third versus the eighth versus the 10th

01:38:00.700 | and so on, as well as the levels of cortisol

01:38:03.660 | and inflammatory markers.

01:38:04.740 | There are a lot of different things measured in this study.

01:38:07.800 | Here's what we know.

01:38:09.320 | Sauna baths, as they're calling them,

01:38:11.300 | resulted in a statistically significant increase

01:38:13.620 | in cortisol concentration

01:38:14.960 | after the first and the 10th sauna session, okay?

01:38:18.640 | So every time you go into the sauna,

01:38:21.160 | you're getting an increase in cortisol.

01:38:22.540 | We know that because the heat is a stressor.

01:38:24.480 | Again, don't think about heat as,

01:38:26.980 | oh, you're just kind of relaxing in the sauna, it's so nice.

01:38:29.240 | You're getting a cortisol response.

01:38:30.620 | Cortisol is a glucocorticoid stress hormone,

01:38:34.620 | as it's sometimes called, which can be a good thing

01:38:37.020 | if it sets in motion a number of other things,

01:38:38.780 | such as the increase in the activity

01:38:40.820 | of the innate immune system.

01:38:41.820 | And indeed that is what they observed.

01:38:44.160 | After, and here I'm paraphrasing,

01:38:46.080 | after the first and 10th sauna baths,

01:38:48.580 | they witnessed an increase in leukocyte count.

01:38:51.860 | Leukocytes are a particular type of cell

01:38:53.580 | of the innate immune system.

01:38:55.060 | However, only after the last sauna session

01:38:57.500 | did this change reach statistical significance

01:39:00.300 | in the trained group.

01:39:01.580 | So what they observed was that athletes who are trained

01:39:05.280 | are used to being in high heat conditions

01:39:07.180 | because of their athletic training.

01:39:09.320 | People who are not trained in athletics

01:39:11.320 | are not used to that.

01:39:13.220 | There are a lot of different ways to look at these data,

01:39:14.860 | but the simplest takeaway is that

01:39:17.320 | if you are already very heat adapted

01:39:19.800 | because you do sauna regularly or you exercise regularly,

01:39:23.300 | well then it's going to take a stronger stimulus

01:39:25.860 | or more sauna, either longer or hotter or more frequent

01:39:30.280 | to get the sorts of increases in innate immune response

01:39:34.700 | as compared to someone who's never done sauna,

01:39:37.020 | who's not exercising regularly.

01:39:39.140 | And that just makes sense.

01:39:40.220 | If something isn't stressful to you,

01:39:41.840 | you're not going to get the stimulation

01:39:43.620 | of that innate immune response.

01:39:45.260 | And the overall takeaway from this study was that

01:39:48.280 | I do believe that if you're feeling run down a little bit

01:39:52.060 | or if you're just trying to keep colds and flus at bay,

01:39:56.460 | having some regular-ish practice of getting into the sauna

01:40:00.140 | for three rounds of 15 minutes

01:40:01.740 | separated by two minute cool off,

01:40:03.340 | you don't necessarily have to do a cold shower

01:40:05.180 | or a cold plunge in between,

01:40:06.420 | although I don't see why you couldn't or wouldn't,

01:40:09.660 | but you could also just get out of the sauna

01:40:11.060 | and be in the cool air and then get back in.

01:40:13.420 | Or perhaps you do something more akin

01:40:15.820 | to what's been shown in other studies

01:40:17.280 | that explore the relationship between heat exposure

01:40:19.560 | and immune response, which is to do two rounds of 20 minutes

01:40:23.360 | or one round of 30 minutes in the sauna,

01:40:25.160 | whatever you can do safely and comfortably.

01:40:26.840 | Keep in mind, safety is key.

01:40:28.100 | Don't harm yourself.

01:40:28.940 | I say that not to protect me, but to protect you.

01:40:31.300 | That sauna is an effective way

01:40:35.480 | of increasing the activity of the innate immune system.

01:40:39.080 | It increases leukocyte levels.

01:40:40.760 | Yes, it increases cortisol levels,

01:40:42.260 | but in a way that promote the activity

01:40:44.560 | of the innate immune system.

01:40:46.160 | However, and here we are back to exactly the same thing

01:40:49.000 | we said about exercise.

01:40:50.580 | If you're already feeling really run down,

01:40:53.040 | feeling kind of heaviness in the body, you don't feel well,

01:40:56.000 | you're starting to get some sniffles,

01:40:57.680 | don't get in a very hot sauna.

01:41:00.240 | But for sake of keeping colds and flus at bay, sure.

01:41:04.640 | Do three rounds of 15 minutes in the sauna

01:41:07.180 | between 176 degrees, 210 degrees,

01:41:09.280 | whatever you can safely tolerate.

01:41:11.080 | Take those two minute breaks in between,

01:41:12.480 | maybe do a cold shower or coolish shower,

01:41:14.880 | maybe just stand outside the sauna in between.

01:41:16.800 | If you're feeling really strong, do a cold plunge

01:41:19.440 | for a minute or two minutes in between.

01:41:21.880 | You don't have to, but you certainly could.

01:41:24.380 | And then get back in and then repeat.

01:41:25.920 | Or just do one 20 minute session or 30 minute session,

01:41:29.100 | all of which have been shown to promote the activity

01:41:31.120 | of the innate immune system.

01:41:32.640 | However, and I realized I said this before,

01:41:34.440 | but I feel like I need to say it again,

01:41:35.940 | especially for you hardcore exercisers

01:41:38.160 | or people that really feel like, oh, I can push through.

01:41:41.580 | If you're already sick and you have the symptoms

01:41:43.740 | of a cold or flu, you want to limit the amount of stress

01:41:46.760 | to your body.

01:41:47.580 | You want to get into bed and sleep.

01:41:49.360 | If you can't sleep, you want to relax.

01:41:51.040 | You do not want to exercise.

01:41:52.940 | You should not exercise.

01:41:54.360 | Not only do you stand to get other people ill

01:41:56.700 | by going places where you exercise,

01:41:58.180 | but even if you exercise at home or in total isolation,

01:42:00.840 | you're going to prolong the duration of that illness.

01:42:03.560 | Because there are many, many reasons

01:42:05.560 | why being still, slowing your circulation,

01:42:08.380 | and allowing your innate, and then in that case,

01:42:10.360 | your adaptive immune system to kick in

01:42:12.120 | and combat those infections is going to get you back

01:42:14.380 | into a regular exercise and work regimen,

01:42:16.400 | much, much faster than would be the case

01:42:18.560 | if you were to push through.

01:42:20.120 | Okay, so now we get to the portion of the discussion

01:42:22.440 | that I think probably many people are anticipating,

01:42:25.920 | which is what can you take to reduce the probability

01:42:30.600 | of getting a cold or flu

01:42:32.360 | or shorten the duration of a cold or flu?

01:42:34.980 | And I actually put out a call on social media.

01:42:37.960 | I asked the question on Instagram and on X,

01:42:40.740 | formerly called Twitter, you know,

01:42:42.560 | what do you do for a cold or flu?

01:42:43.880 | And what are you curious about

01:42:45.320 | in terms of what one can take for cold or flu?

01:42:47.440 | And I got thousands upon thousands of answers.

01:42:51.240 | However, many of those answers

01:42:52.680 | converged on some common things.

01:42:54.360 | Things like taking garlic.

01:42:56.160 | I heard, for instance, that some people

01:42:57.440 | are chewing a raw clove of garlic every day

01:42:59.400 | during the winter.

01:43:00.900 | I heard about people who take fermented garlic.

01:43:03.760 | Some people swear by echinacea.

01:43:06.160 | Some people swear by echinacea, vitamin C, and zinc.

01:43:09.280 | Now, there are far too many compounds

01:43:11.260 | that exist in the wellness

01:43:13.120 | and indeed in the medical literature

01:43:14.720 | to cover all of them.

01:43:15.880 | So I'm going to highlight a few

01:43:17.180 | that I think are especially interesting

01:43:19.120 | and that have been shown in peer-reviewed science

01:43:21.520 | to be potentially useful.

01:43:23.680 | Some of these you've heard of before,

01:43:25.960 | and some of them I think are going to be surprising

01:43:28.040 | or at least new to you.

01:43:29.800 | First, let's consider what most people believe

01:43:32.160 | to be a very effective way to hasten colds or flus,

01:43:36.200 | that is to make them last shorter duration of time

01:43:39.320 | than they would otherwise,

01:43:41.160 | maybe even prevent colds or flus.

01:43:43.000 | The big one there is vitamin C.

01:43:44.560 | We hear all the time, vitamin C, antioxidant.

01:43:47.300 | I grew up in an area

01:43:48.680 | where the Nobel prize-winning chemist, Linus Pauling,

01:43:52.220 | who was a fanatic about vitamin C,

01:43:53.720 | he took many, many grams of vitamin C each day,

01:43:56.840 | used to tout the benefits of vitamin C.

01:43:59.100 | Here's the deal.

01:44:01.840 | There is some evidence, and it's not great, frankly,

01:44:06.360 | that points to the fact that taking six to eight grams,

01:44:10.360 | grams, so that's 6,000 to 8,000 milligrams

01:44:14.000 | of vitamin C per day.

01:44:15.120 | That is a lot of vitamin C.

01:44:16.820 | Each day can perhaps delay the onset of a cold

01:44:22.980 | or shorten the duration of a cold.

01:44:26.440 | So here we're talking about very high doses

01:44:28.980 | and not a very robust effect.

01:44:31.560 | I should mention that for most people

01:44:33.680 | who aren't accustomed to taking much vitamin C,

01:44:36.280 | if you were to take six to eight grams of vitamin C

01:44:38.860 | in capsule or powder or pill form,

01:44:40.860 | chances are you're going to experience

01:44:42.280 | some significant gastric distress.

01:44:44.840 | Some people can build up to that level

01:44:47.000 | or take it with food in a way

01:44:48.360 | that doesn't cause that gastric distress,

01:44:50.880 | but many people will experience gastric distress.

01:44:54.200 | There's been a lot said about vitamin C

01:44:55.760 | and its other potential roles in our physiology,

01:44:57.920 | and I don't want to touch on those now

01:44:59.320 | because it may have some interesting roles

01:45:01.000 | in other aspects of our physiology,

01:45:02.600 | but I have to say that in scouring the literature

01:45:06.760 | on vitamin C, I encountered a recent paper,

01:45:10.680 | so this was published in 2023,

01:45:13.340 | and the title of this paper is "Retraction."

01:45:17.360 | Extra dose of vitamin C based on a daily supplementation

01:45:20.300 | shortens the common cold,

01:45:21.400 | a meta-analysis of nine randomized controlled trials.

01:45:24.260 | What is this paper that was recently published?

01:45:27.240 | Why is retraction the first word in the title?

01:45:30.660 | Well, it turns out that the meta-analysis

01:45:33.640 | of nine randomized controlled trials

01:45:35.280 | showing a small but significant improvement

01:45:40.080 | in the outcomes for colds and flus

01:45:41.680 | or reduction in probability of getting colds and flus,

01:45:44.760 | that study was retracted,

01:45:46.580 | and it was retracted on the basis of multiple instances

01:45:51.280 | of an error in which the placebo groups

01:45:53.720 | had been double-counted in trials

01:45:55.240 | more than the two intervention arms,

01:45:56.560 | so there were some serious data analysis flaws

01:45:59.600 | in that meta-analysis.

01:46:00.860 | Now, that is not to say that vitamin C is of zero benefit

01:46:04.880 | for reducing the probability of colds and flus,

01:46:07.880 | but I must say, provided that you're getting

01:46:10.720 | sufficient amounts of vitamin C from your food intake,

01:46:13.080 | maybe you also get a little bit

01:46:14.500 | in your vitamin mineral supplement,

01:46:16.400 | or if you take a foundational supplement

01:46:18.440 | like AG1 or something similar,

01:46:20.520 | almost certainly you're getting enough vitamin C,

01:46:23.280 | it does not seem that taking high doses of vitamin C,

01:46:27.400 | and I would place six to eight grams of vitamin C

01:46:29.660 | in the high dose range,

01:46:31.000 | is going to be effective for treating

01:46:34.200 | or preventing colds and flus.

01:46:35.880 | So more data may arrive in the near future,

01:46:38.240 | but vitamin C is probably not a very good investment

01:46:40.720 | if you're taking it solely for the purpose

01:46:42.700 | of enhancing your immune system function

01:46:45.320 | and staving off colds and flus.

01:46:47.560 | Now, what about vitamin D?

01:46:48.640 | We hear a lot these days about the importance

01:46:50.200 | of having sufficient vitamin D levels,

01:46:51.760 | and ideally everyone would get their vitamin D levels

01:46:54.160 | measured by regular blood tests.

01:46:56.080 | I do get my blood work done every six months,

01:46:57.960 | I find it be incredibly informative,

01:47:00.040 | tells me what's going on below the hood

01:47:02.040 | in ways that I never could be aware of

01:47:04.480 | were I not to get that test,

01:47:05.580 | but I realized that there's a cost to those tests

01:47:08.140 | and not everyone can afford them.

01:47:09.840 | I think most physicians would agree that

01:47:13.560 | supplementing with anywhere from 1,000 to 2,000 IU

01:47:17.200 | of vitamin D per day is probably safe for most people

01:47:20.100 | and will buffer that level of vitamin D in their system,

01:47:23.920 | such that they're unlikely to be deficient

01:47:26.680 | and unlikely to far exceed what's safe in the body.

01:47:30.300 | However, there are people who need higher levels

01:47:34.280 | of vitamin D supplementation in order to achieve

01:47:36.540 | sufficient amounts of vitamin D for their mental health

01:47:38.780 | and physical health.

01:47:39.620 | I mean, vitamin D is involved in a lot of different

01:47:41.760 | processes in the brain and body.

01:47:44.660 | Now, it is clear that people who are vitamin D deficient,

01:47:48.900 | so these are people whose vitamin D levels

01:47:50.540 | have been measured,

01:47:51.560 | oftentimes have diminished immune system function

01:47:55.800 | and are more prone to acute respiratory tract infections.

01:47:59.880 | There's a very lengthy and very interesting review

01:48:02.340 | entitled "Vitamin D Supplementation to Prevent

01:48:04.780 | Acute Respiratory Tract Infections,

01:48:06.500 | Systematic Review and Meta-analysis

01:48:08.100 | of Individual Participant Data."

01:48:10.140 | This is a beast of a thing.

01:48:12.040 | I did read it all.

01:48:13.540 | Very, very interesting.

01:48:14.380 | Many, many studies.

01:48:15.440 | The exact takeaways from a large review like this

01:48:19.800 | of 25 randomized control trials is a little bit tricky.

01:48:24.240 | I mean, they did conclude that vitamin D supplementation

01:48:26.500 | did reduce the risk of acute respiratory tract infection

01:48:29.140 | among all the participants.

01:48:31.140 | However, the degree of prevention

01:48:35.140 | was small to moderate in some cases.

01:48:37.620 | They did point out, however,

01:48:38.960 | that just because people with low levels of vitamin D

01:48:42.040 | tend to get colds and flus

01:48:43.740 | more often than people that don't,

01:48:45.900 | does not necessarily mean that vitamin D deficiencies

01:48:49.860 | are the reason for that.

01:48:51.060 | For instance, we know that people

01:48:53.140 | that get regular sunlight exposure,

01:48:55.260 | and as everyone knows, I'm a big, big proponent

01:48:58.060 | of getting sunlight in your eyes as early as possible

01:49:01.380 | in the day after waking up.

01:49:02.500 | And if it's cloudy out to get even more time outside,

01:49:04.860 | if you can, and if you can't get access to sunlight

01:49:07.220 | for whatever reason,

01:49:08.380 | to perhaps invest in a 10,000 lux light tablet,

01:49:11.460 | you can find these online at reasonable cost,

01:49:13.580 | you know, $100 to $200 in some cases.

01:49:16.000 | Getting sunlight sets in motion

01:49:20.780 | a huge number of different things,

01:49:22.580 | including increasing the amount of vitamin D in your system,

01:49:26.840 | but a bunch of other things as well.

01:49:27.980 | Increases in cortisol, increases in dopamine,

01:49:30.040 | increases in serotonin that cascade toward

01:49:33.720 | and relate to improved immune system function.

01:49:36.860 | So what is the takeaway here?

01:49:38.900 | I think that for most people supplementing

01:49:40.620 | with 1,000 to 2,000 international units of vitamin D

01:49:44.420 | is probably safe.

01:49:46.100 | However, if you need more vitamin D,

01:49:48.200 | you won't know that unless you take a vitamin D test,

01:49:50.900 | that is you measure the amount of vitamin D

01:49:52.500 | in your bloodstream.

01:49:53.580 | And some people indeed need 5,000 to 10,000 IU

01:49:56.420 | of vitamin D per day,

01:49:57.420 | but you don't want to overdose yourself on vitamin D.

01:50:00.460 | That is if you already have sufficiently high levels

01:50:02.520 | of vitamin D in your system,

01:50:04.320 | you're getting sufficient sunlight,

01:50:06.380 | well then taking 10,000 or more international units

01:50:10.660 | of vitamin D could possibly be detrimental.

01:50:13.240 | I think it's fair to say based on the meta analysis

01:50:17.180 | and review that I mentioned a moment ago,

01:50:19.700 | the other papers that I was able to glean

01:50:21.820 | that vitamin D itself is unlikely to be

01:50:25.740 | the sole protectant against colds and flus,

01:50:27.840 | but it's probably a good thing to include

01:50:29.820 | in your general kit of nutrition and supplementation tools

01:50:33.020 | if your goal is to keep your innate immune system

01:50:35.580 | fighting off colds and flus sufficiently.

01:50:38.080 | Other things that could perhaps support

01:50:39.580 | the innate immune system are going to be,

01:50:41.040 | as I mentioned earlier,

01:50:41.880 | the things that support the gut microbiome.

01:50:43.400 | So those low sugar fermented foods,

01:50:45.060 | maybe a prebiotic probiotic capsule,

01:50:46.900 | maybe something like Athletic Greens AG1,

01:50:50.580 | although certainly you could achieve

01:50:52.240 | sufficient microbiome support from foods if you're careful

01:50:55.820 | and intentional about the foods that you select.

01:50:58.120 | Now the other compound or substance that we often hear about

01:51:00.760 | in the context of colds or flus is echinacea.

01:51:04.200 | Echinacea is a compound that has been proposed

01:51:07.080 | to improve immune system function.

01:51:08.780 | Now, when you go into the data and you explore

01:51:11.240 | what does taking echinacea tinctures

01:51:13.400 | or other forms of echinacea really do

01:51:15.480 | to avoid colds and flus?

01:51:17.320 | The answer that comes back is not much, if anything.

01:51:20.480 | Now, is taking echinacea dangerous?

01:51:22.880 | Probably not.

01:51:23.720 | However, it has been shown in a few studies

01:51:26.540 | that people that take echinacea regularly at high doses

01:51:29.840 | can potentially impede the function

01:51:33.060 | of their innate immune system.

01:51:34.200 | That is reductions in white blood cell count,

01:51:36.180 | reductions in those natural killer cells.

01:51:38.320 | So my suggestion would be,

01:51:40.160 | if you absolutely love echinacea for whatever reason,

01:51:42.920 | you're convinced that it helps you,

01:51:44.160 | that you reserve to taking it

01:51:45.480 | when you're starting to feel a little bit run down

01:51:47.040 | or perhaps just in the winter month,

01:51:48.920 | not months, plural, but month,

01:51:51.080 | when you're most prone to those cold and flu infections,

01:51:53.440 | but then not taking it continuously throughout the year

01:51:55.920 | and certainly not for more than four weeks at a time.

01:51:58.620 | But again, if you're doing that,

01:52:00.320 | just know that there aren't really

01:52:02.440 | any strong scientific data to support the use of echinacea.

01:52:05.560 | By contrast, there are pretty darn good data

01:52:08.400 | that support supplementing with zinc

01:52:10.600 | as a way to combat colds and flus, in particular, colds.

01:52:13.580 | Now, here, the dosages really matter.

01:52:17.520 | It's been shown that if you take less than 75 milligrams

01:52:21.160 | of zinc in supplement form

01:52:23.440 | to try and impact the probability of getting

01:52:26.420 | or shortening a common cold, it's not going to work.

01:52:29.700 | You need to take 100 milligrams or more.

01:52:31.960 | And now 100 milligrams or more of zinc,

01:52:33.660 | for some people, is going to cause some gastric distress

01:52:36.440 | if you take it on an empty stomach.

01:52:38.280 | I've actually made the mistake of taking,

01:52:40.160 | I think it was 50 milligrams of zinc on an empty stomach,

01:52:42.720 | and I felt really nauseous, did not feel well.

01:52:45.400 | So don't take zinc on an empty stomach.

01:52:47.160 | And if you're trying to shorten a cold or flu

01:52:50.160 | that you think you've already contracted,

01:52:51.640 | or you're trying to keep a cold or flu at bay

01:52:53.520 | 'cause you were around people with colds or flus,

01:52:55.180 | or you're just worried about it,

01:52:56.500 | taking 100 milligrams of zinc,

01:52:58.040 | perhaps divide it up into two doses of 50 milligrams each,

01:53:01.820 | or maybe 100 milligrams all at once,

01:53:03.400 | but making sure that you take that

01:53:04.840 | with at least a moderately sized or full meal

01:53:07.880 | certainly could be advantageous.

01:53:09.440 | Keep in mind that people that are older than 65

01:53:12.240 | are perhaps the ones that need to supplement zinc the most.

01:53:15.580 | Also keep in mind that children,

01:53:17.400 | meaning people younger than 15,

01:53:21.220 | should probably not supplement with too much zinc.

01:53:23.640 | It can be problematic.

01:53:24.620 | And certainly pregnant women should talk to their doctor

01:53:26.900 | before supplementing with zinc.

01:53:28.500 | Indeed, anytime you're going to take anything,

01:53:30.500 | whether or not you're young, old, pregnant or not,

01:53:33.120 | you should consult your physician before you take anything

01:53:35.340 | or remove anything from your health protocols.

01:53:37.480 | One of the more interesting aspects

01:53:38.920 | of supplementing with zinc

01:53:40.100 | that I was able to find in the literature

01:53:41.980 | is a three times faster recovery rate

01:53:45.540 | for people that already contracted a cold.

01:53:48.320 | So in this study, people weren't taking 100 milligrams,

01:53:50.640 | but the dosage came pretty close.

01:53:52.160 | They were taking 90 milligrams per day of zinc acetate,

01:53:56.600 | and they experienced a three times faster recovery rate

01:54:00.040 | from that cold compared to people

01:54:02.120 | who were not taking the zinc.

01:54:03.320 | Now, of course, there could be other factors as well,

01:54:05.020 | but the study was fairly convincing.

01:54:06.880 | So given that zinc is fairly low cost,

01:54:09.580 | given that it's generally safe for most people,

01:54:11.980 | and the fact that if you take it with food,

01:54:14.640 | it doesn't cause any discomfort,

01:54:17.200 | supplementing with zinc at a level of anywhere

01:54:19.040 | from 90 to 100 milligrams per day,

01:54:22.120 | probably no more than 120 per day,

01:54:24.960 | seems like a logical way to stave off colds and flus

01:54:28.000 | and reduce the duration of a cold or flu

01:54:30.500 | should you contract one.

01:54:31.700 | Now, I want to be very clear

01:54:32.840 | that I've been talking about colds and flus

01:54:34.520 | kind of in concert,

01:54:36.420 | kind of treating them more or less as the same thing.

01:54:38.720 | Some of that is for sake of time and simplicity.

01:54:41.380 | Most all of the studies showing a benefit of zinc

01:54:43.420 | are studies showing the benefit of zinc

01:54:45.580 | for the treatment or the hastening of colds,

01:54:48.820 | not for flus specifically.

01:54:50.700 | However, I consulted with a few physicians

01:54:53.240 | and one of whom is expert in this area,

01:54:55.940 | and he said, "I didn't see any reason

01:54:57.100 | why you wouldn't take zinc if you had a flu."

01:55:00.060 | There's no reason to think

01:55:00.900 | that it would introduce any kind of increased risk,

01:55:03.180 | but again, consult with your physician before taking

01:55:05.280 | or removing anything from your supplement regimen.

01:55:07.560 | Now, a lot of the compounds that we're discussing

01:55:09.360 | are sort of conventional in the sense that

01:55:11.340 | I think most people have probably heard of them already.

01:55:13.500 | Perhaps the most esoteric sounding one thus far

01:55:15.660 | is echinacea, which we established

01:55:17.940 | probably not very helpful for colds or flus,

01:55:21.540 | but we've been talking about vitamin C,

01:55:22.640 | we've been talking about zinc, vitamin D,

01:55:24.940 | making sure you're getting your sunlight,

01:55:26.100 | supporting your microbiome, and so on and so on.

01:55:28.980 | One compound that I'm guessing most people

01:55:31.120 | perhaps have not heard of,

01:55:32.640 | but that is very interesting that in fact I've taken before

01:55:35.500 | and that I stock in my supplement cabinet

01:55:38.480 | in case I feel like I'm coming down with something,

01:55:40.940 | is N-acetylcysteine or NAC.

01:55:43.600 | What is NAC?

01:55:44.780 | NAC is a precursor to glutathione.

01:55:47.720 | What is glutathione?

01:55:48.880 | Glutathione is the master antioxidant.

01:55:51.720 | It's involved in reducing

01:55:53.000 | what are called reactive oxygen species,

01:55:55.440 | which build up in cells that are very metabolically active.

01:55:59.060 | Reactive oxygen species build up even more

01:56:01.380 | in cells that are under stress or a body that's under stress.

01:56:04.380 | And it also has the property

01:56:06.520 | of reducing reactive nitrogen species.

01:56:09.280 | Reactive oxygen and reactive nitrogen species

01:56:11.940 | significantly increase under conditions of infection

01:56:14.760 | and having sufficient levels of glutathione is a good thing.

01:56:18.460 | Now, N-acetylcysteine is used in certain clinics overseas

01:56:21.940 | and in the US as a way to treat cystic fibrosis

01:56:25.060 | because it's also a mucolytic.

01:56:27.100 | And cystic fibrosis is the buildup of fluid in the lungs

01:56:29.920 | and a mucolytic substance is something

01:56:31.920 | that loosens up the mucus and allows it to flow more readily

01:56:35.860 | out of different cavities of the body,

01:56:37.320 | including the lungs, the nasal passages and sinuses.

01:56:40.880 | And indeed last winter, I did unfortunately get a cold.

01:56:45.040 | I told you about once every 18 to 24 months, I get a cold

01:56:47.760 | and it was a pretty nasty one.

01:56:49.800 | I was feeling super congested.

01:56:51.200 | At first, I thought it was an ear infection.

01:56:53.080 | Pretty quickly, I realized I had a cold

01:56:55.280 | and I was feeling so congested, I wasn't sleeping well.

01:56:57.720 | And it was suggested to me to take N-acetylcysteine.

01:57:00.080 | I ended up doing that at a dosage of anywhere

01:57:02.280 | from 600 to 900 milligrams, three times per day.

01:57:05.440 | So it was a 600 to 900 milligram capsule,

01:57:07.960 | depending on which brand I purchased.

01:57:10.160 | A lot of different versions of this out there on the market.

01:57:12.240 | I took it morning, late morning and afternoon.

01:57:14.520 | And indeed it is a powerful mucolytic.

01:57:17.140 | The mucus just starts flowing out.

01:57:18.520 | You better have an extra box of tissues handy.

01:57:20.680 | And that greatly relieved the pressure in my sinuses.

01:57:23.340 | And the reason I liked using NAC is

01:57:26.240 | because I've actively avoided using decongestants

01:57:29.640 | that one can purchase over the counter.

01:57:31.000 | Most decongestants are of the alpha-1 agonist variety.

01:57:35.240 | What's an alpha-1 agonist?

01:57:36.320 | It causes vasoconstriction.

01:57:38.160 | That vasoconstriction can be beneficial

01:57:40.160 | in preventing some of the intense congestion

01:57:42.560 | that one gets when you have a sinus infection

01:57:45.120 | or a cold or a flu.

01:57:46.840 | But then when those decongestants wear off,

01:57:50.520 | one tends to get a rebound increase in congestion

01:57:53.240 | and it's really painful, headache, et cetera.

01:57:55.340 | In addition, some over the counter decongestants

01:57:57.840 | can be habit forming.

01:57:59.080 | Not necessarily addictive, but habit forming.

01:58:01.000 | And they don't seem to have

01:58:02.120 | any other positive health benefits.

01:58:03.960 | So I prefer not to take decongestants if I can avoid it.

01:58:07.600 | I had a very good experience with NAC.

01:58:09.760 | And the use of NAC, N-acetylcysteine, as a decongestant

01:58:14.760 | and also as a way to prevent getting colds and flus

01:58:17.880 | is not an entirely new idea.

01:58:19.480 | In fact, there's a paper dating back to 1997

01:58:22.420 | entitled "Attenuation of Influenza-like Symptomology

01:58:26.560 | "and Improvement of Cell-Mediated Immunity

01:58:29.100 | "with Long-Term N-acetylcysteine Treatment."

01:58:31.980 | Now, in this study, they looked at people

01:58:33.520 | who were taking 600 milligrams of N-acetylcysteine

01:58:36.040 | twice per day for six months.

01:58:39.240 | And what they observed is that the people

01:58:40.660 | who took N-acetylcysteine

01:58:42.280 | had a significantly lower probability

01:58:44.280 | of contracting influenza.

01:58:46.820 | Now, this is but one study.

01:58:48.520 | There've been a few other studies

01:58:49.960 | and unfortunately there isn't a large body of research

01:58:52.120 | looking at NAC as a preventive for colds and flus.

01:58:54.940 | But the data in this paper are interesting enough

01:58:56.840 | and I was compelled by them enough to seek out a physician

01:59:01.160 | who I noticed was answering my prompts on social media

01:59:04.920 | about what do you use for colds and flus?

01:59:07.000 | And when I put that out there, as I mentioned,

01:59:08.400 | I got thousands of responses

01:59:10.200 | on both Twitter X and on Instagram.

01:59:12.920 | And one particular physician

01:59:14.280 | who happens to have a YouTube account,

01:59:15.820 | his name is Dr. Schwelt.

01:59:17.600 | He's a medical doctor.

01:59:18.580 | He works in an intensive care unit

01:59:20.460 | and he deals with a lot of patients

01:59:22.080 | who have different strains of flu.

01:59:23.760 | In fact, he was the one that cued me

01:59:25.760 | to the fact that this year,

01:59:27.240 | there seems to be a fair number

01:59:29.440 | of H1N1 flu virus going around.

01:59:31.380 | And remember the H1N1 flu virus,

01:59:33.200 | while it's not deadly to everyone,

01:59:35.520 | it can be quite severe in some people.

01:59:37.200 | So we do want to be on the lookout for

01:59:39.360 | and trying to avoid getting H1N1 if we can.

01:59:42.220 | I spoke to Dr. Schwelt.

01:59:44.500 | He was very generous with his knowledge

01:59:46.480 | about N-acetylcysteine.

01:59:47.920 | He did acknowledge, and I'll acknowledge again here,

01:59:50.520 | that it would be great to get more randomized

01:59:52.240 | control trial data on N-acetylcysteine.

01:59:55.200 | But we did talk about this paper, this 1997 paper.

01:59:57.880 | And he did mention that he and other clinicians

02:00:01.960 | that are forced to be in the hospital

02:00:04.080 | dealing with patients all through the winter

02:00:05.720 | and all year long,

02:00:06.760 | they're getting bombarded with cold and flu exposure

02:00:08.920 | all the time,

02:00:10.200 | that they, meaning he and some of his colleagues,

02:00:13.760 | deliberately take N-acetylcysteine as a preventative

02:00:16.260 | to try and reduce the probability

02:00:17.920 | of getting colds and flus.

02:00:19.280 | And while we don't want to make too much

02:00:20.600 | of any one study or anecdotal data,

02:00:23.200 | which is what we're describing when I tell you

02:00:24.720 | about a physician who told me this

02:00:26.140 | or what I did and experienced that,

02:00:28.500 | I think it is worth paraphrasing the study

02:00:30.480 | that I mentioned before.

02:00:32.500 | NAC prevented the symptomatic forms caused by,

02:00:35.600 | here they're talking about the A, H1N1 influenza virus

02:00:38.480 | quite efficiently.

02:00:39.340 | Since the large majority of infected subjects

02:00:41.480 | in the placebo group, 79%,

02:00:44.040 | developed clinically apparent disease

02:00:46.360 | versus only 25% in the NAT group.

02:00:48.900 | In other words, approximately 80% of people in the study

02:00:52.020 | who did not take N-acetylcysteine got influenza,

02:00:56.140 | whereas only 25% of the people

02:00:58.760 | who were taking N-acetylcysteine contracted influenza.

02:01:01.860 | So that's a fairly dramatic difference.

02:01:03.540 | And certainly the fact that N-acetylcysteine

02:01:06.140 | has been shown to increase glutathione,

02:01:08.300 | that's its primary mechanism of action as far as we know,

02:01:11.640 | and the fact that increases in glutathione

02:01:14.940 | are generally healthy and good for us,

02:01:16.580 | and the fact that N-acetylcysteine is still available

02:01:20.020 | legally over the counter in the US,

02:01:21.660 | at least currently it is, some years back,

02:01:25.020 | as you may have heard,

02:01:26.460 | the FDA called for removal of N-acetylcysteine

02:01:28.980 | from over the counter sales.

02:01:30.840 | That I should point out was based on the fact

02:01:32.720 | that certain supplement companies were making claims

02:01:35.380 | about N-acetylcysteine as a treatment for hangover

02:01:38.360 | and making a bunch of other claims

02:01:39.580 | for which there was no real data,

02:01:41.620 | but either because the FDA was effective

02:01:43.600 | in getting those companies to cease those claims

02:01:45.980 | and/or because of advocacy groups,

02:01:47.900 | which worked very hard to try and keep N-acetylcysteine

02:01:51.800 | available for over the counter sales.

02:01:53.680 | As far as I know,

02:01:54.520 | at least right up until prior to recording this episode,

02:01:57.340 | N-acetylcysteine is available for sale over the counter.

02:02:00.980 | So whether or not you decide to use N-acetylcysteine

02:02:03.420 | as a preventative,

02:02:04.580 | and there again, the dosage is about 1200 milligrams per day

02:02:07.480 | divided into two different dosages of 600 milligrams each,

02:02:10.220 | or if you decide to take N-acetylcysteine

02:02:12.780 | in the manner that I did, which was not as a preventative,

02:02:15.740 | but once I had a cold, couldn't fight it off,

02:02:19.020 | apparently got the cold,

02:02:20.260 | decided to take 900 milligrams three times per day,

02:02:22.820 | avoiding that intake close to sleep

02:02:24.420 | because it did disrupt my sleep

02:02:26.140 | if I took it too close to sleep

02:02:27.540 | because of the way that the mucus would flow so readily.

02:02:30.060 | You know, essentially, I know it sounds gross,

02:02:31.880 | but I felt like it was filling up the back of my throat,

02:02:33.560 | so-called post-nasal drip,

02:02:34.720 | but it felt like post-nasal waterfall.

02:02:36.620 | And I decided to restrict my intake of N-acetylcysteine

02:02:39.380 | to earlier in the day only.

02:02:41.340 | And of course, there's the third option,

02:02:42.840 | which is that you opt to not take N-acetylcysteine

02:02:45.420 | until more randomized control trials are published,

02:02:48.280 | or not take N-acetylcysteine at all

02:02:49.800 | because you're of the sort that thinks,

02:02:51.900 | okay, with some sleep, a hot shower, a good meal,

02:02:54.420 | some chicken soup, maybe a little garlic, who knows?

02:02:57.440 | Maybe you have some other tools and techniques

02:02:59.580 | that you like, you like that ginger tea, lemon, et cetera.

02:03:01.780 | Maybe that's all you need.

02:03:03.380 | And if that's all you need and that's all you want

02:03:05.660 | in order to deal with a cold or flu, be my guest.

02:03:08.940 | I certainly am not here to convince anyone

02:03:11.260 | that you have to take a certain supplement,

02:03:13.020 | but I did feel like I would be remiss

02:03:15.080 | if I didn't cover what are generally referred to

02:03:17.820 | as the so-called preventatives and treatments

02:03:20.340 | for colds and flus, things like zinc, vitamin D, vitamin C.

02:03:23.400 | We now know that unfortunately, vitamin C gets a,

02:03:26.260 | probably a D- or an F at least as the data stand now,

02:03:28.920 | but there are these other things like zinc

02:03:30.940 | and potentially N-acetylcysteine that can be beneficial

02:03:34.900 | in shortening the duration of colds or flus

02:03:37.880 | and perhaps even helping us avoid

02:03:39.940 | getting colds or flus all together.

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02:05:30.600 | I'd like to thank you for today's discussion

02:05:32.500 | about the biology of colds and flus,

02:05:35.020 | about the biology of the immune system,

02:05:36.920 | and how to avoid and treat colds and flus.

02:05:39.840 | And last, but certainly not least,

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02:05:43.920 | (upbeat music)

02:05:46.500 | (upbeat music)

How to Prevent & Treat Colds & Flu

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