- Welcome to the Huberman Lab Podcast, where we discuss science and science-based tools for everyday life. I'm Andrew Huberman, and I'm
a professor of neurobiology and ophthalmology at
Stanford School of Medicine. Today, we continue in our
discussion about sensation or how we sense things. On previous episodes, we
talked about sensing light and sound waves for things
like vision and hearing. Today, we are going to
talk about our sense of self or what's called interoception. Interoception is our sensing of our internal landscape,
things like our heartbeat, our breathing, and our gut,
how full our gut might happen to be, or how empty our
gut might happen to be. But also our inner landscape
with respect to chemistry, how acidic, or how good or
bad we feel on the inside. This discussion about sense of self and interoception
has many important, actionable items that relate to bodily health and brain health, and believe it or not, our ability to perform well
or perform poorly in life. Indeed, it has profound influence
on our rates of healing. So today we are going to talk
about all the aspects of our inner landscape and how our
brain and body communicate. And there will be many
actionable protocols as we go along that discussion. Before we begin our discussion
about sense of self, I want to highlight some very
recently published research findings that I believe
are immediately actionable and that everybody should be aware of. These are data that were
published by my colleague, Justin Sonnenberg's laboratory at Stanford University School of Medicine, and the data were published
in the Journal Cell, which is a very high
stringency cell press journal. So phenomenal data. What this study showed was
that individuals given a high fiber diet actually
experienced less diversity of what's called the gut microbiome. The number of positive or
health promoting bacteria in the gut was actually
reduced by a high fiber diet, whereas individuals that ate just a couple of servings of fermented food each day, experience important
and beneficial increases in anti-inflammatory markers. And that could be traced
back to improvements in the gut microbiome
diversity, the diversity of bugs, literally little bacteria that live in the gut,
which might sound bad, but they are actually
very health promoting. I'm going to get into all
the details of this study later in the episode, but I just wanted to
emphasize these findings because they are immediately actionable. I think for most people
ingesting one or two servings of fermented food each day is
reasonable and does not bring with it tremendous costs or
tremendous inconvenience. And I think many people are
ingesting high fiber diets thinking that that's the best way to improve their gut microbiome. So while these data may prove
to be controversial among the folks out there in the
nutrition community, that really high fiber diet, I want to just emphasize that
these data were looked at in a very unbiased way. They were done with large scale screens of all sorts of inflammatory markers. There was no specific hypothesis going in. It was purely exploratory,
but the data are very clear. It doesn't mean you shouldn't
eat fiber doesn't mean that fiber is bad, but it really shows that
eating fermented foods, just one or two servings a day, and maybe even ramping up to
three or four servings per day can be very beneficial for
many aspects of health. Before we go any further. I'd like to emphasize that this
podcast is separate from my teaching and research roles
at Stanford, it is however, part of my desire and effort
to bring zero cost to consumer information about science
and science related tools to the general public. In keeping with that theme, I'd like to thank the
sponsors of today's podcast. Our first sponsor is Roka. Rocha makes sunglasses and eyeglasses that are of the
absolutely highest quality. The company was founded by
two All-American swimmers from Stanford and everything
about their sunglasses and eyeglasses is developed
with performance in mind. I've spent my career
working on the visual system and its various functionings within the brain and within the eye, Roka sunglasses and
eyeglasses are so phenomenal because they allow the visual system to do what it does best, which is to adjust to changes
in what we call luminance or brightness, with many
sunglasses out there and with many eyeglasses as well, if the brightness in the room changes or you get cloud cover, or you walk into a shadow, you have to
take the glasses on or off, you can't see as well. But the folks at Roka really understand how the visual system works. And so they've designed their sunglasses and eyeglasses such that you
never experienced that shift. You can walk into a shadow. The amount of sunlight can change. You can go into a dark room, et cetera, provided there's enough
light to see you're going to see everything crystal clear. In addition you see
everything crystal clear because the lens quality is terrific and the sunglasses and
eyeglasses are very lightweight. So you don't even notice
that they're on your face. Also the sunglasses and eyeglasses are designed for performance. You can use them while
running or while cycling. Even if you sweat, they
won't slip off your face. And as I mentioned before,
they're very lightweight. So everything about
these glasses is terrific and they have a terrific aesthetic. They have a lot of different
styles to select from. And unlike a lot of performance
eyeglasses out there, they won't make you look like a cyborg. You could wear them to
dinner or to somebody's home. And they look really nice. If you'd like to try Roka glasses, you can go to Roka that's
ROKA.com and enter the code Huberman to save 20% off your
first order, that's Roka, ROKA.com and enter the
code Huberman at checkout. Today's podcast is also brought
to us by Inside Tracker. Inside Tracker is a
personalized nutrition platform that analyzes data from your blood and DNA to help you better meet your health goals. I'm a big believer in getting
regular blood work done for the simple reason that many of
the factors that impact your immediate and long-term
health can only be assessed, can only be measured from
a quality blood test. And now with the advent
of quality DNA tests, you can get further insight into the status of your
immediate and long term health. One of the problems with a
lot of blood and DNA tests that are out there, however,
is you get the numbers back, you get the levels of
metabolic factors, hormones, et cetera, but you don't
get any information about what to do with those numbers
or how to actually shift them in the direction that you want to. With Inside Tracker, they have this very easy to use dashboard and that dashboard makes
it very clear, not just what your levels of
hormones, et cetera are, but what actions to take in
terms of nutrition or exercise or other lifestyle factors
to bring those numbers into the appropriate ranges for you. If you'd like to try inside tracker, you can go to insidetracker.com/huberman. And if you do that, you'll get 25% off any
of Inside Trackers plans. Just use the code Huberman at checkout. That's insidetracker.com/huberman to get 25% off any of
Inside Trackers plans. Today's podcast is also
brought to us by Headspace. Headspace is a meditation app that's backed by 25 peer
reviewed published studies and has over 600,000 five-star reviews. I started meditating
when I was in my teens, but for many years I found it
hard to maintain a meditation practice, I don't think
I'm alone with that. I think many people start meditating. They'll do it for a few
weeks or a few months, or maybe even a year. And then they'll give up
the meditation practice. And we know from so many
peer reviewed studies that meditation has a number of
very positive effects on our brain health, our ability to
focus and our bodily health. So it's a great thing, we
probably should all be doing it, but most of us, including myself, have found it hard to stick
to a meditation practice. Then I started using the Headspace
app and what I found is I could be very consistent
with my meditation practice because they have
meditations that are short, meditation that are medium length, and meditations that are a bit longer, all of which benefit me. The meditations that they have
also are of different styles. You can try different forms of meditation. I particularly like having
a guide for my meditation. It just helps me stay focused, helps me stay on track and
I'm able to derive all those regular benefits of meditation
and keep the practice up on a regular basis, if
you want to try Headspace, you can go to headspace.com/specialoffer. And if you do that, you'll get a one month totally free trial. And with that, you'll get all of Headspace's meditations, the
full library of meditations. You just go to
headspace.com/special offer, and you get all of their
meditations for one free month and you get to try it, if you
don't like it, you can stop. But I think you will enjoy it. I certainly enjoy meditation and we know that it's very
beneficial for all of us. If you're somebody who cares about your immediate and long-term health, and if you're somebody who's
interested in performance of any kind in work in
relationships, et cetera, today's topic I believe is among the more important ones for you. Of all the topics I could cover, this thing that we call sense of self, which is also called
interoception has perhaps the most foundational level of
importance for all that. We feel all that we do and all
that we are capable of doing. In fact I will go so far as to say that interoception or our ability to sense our inner real estate
is right there next to sleep. And perhaps one other feature
of our health and bodily function that primary early
determine how good we feel in the now in the short
term, and in the longterm, and sets the stage for everything
we are capable of doing. And if we don't take care of this thing that we call interoception, just like if we don't take care of sleep, we cannot perform well and
we will not remain healthy. Interoception and sense of
self are essentially the same thing, I will use those
terms interchangeably, at least for sake of today's discussion. And I promise that if you
can learn a little bit about the mechanisms of self sensing, of understanding what's going
on in your internal milieu, as we say your internal environment, you will position yourself
to do some very simple things that can lead to outsize positive effects on everything from sleep
to body composition, to mental focus, to mood, your
ability to regulate stress, and indeed even your ability
to heal and recovery from injuries of different kinds,
brain injury and bodily injury. So sense of self is absolutely crucial. It's sometimes called our sixth sense, right alongside the other five
senses like hearing vision, touch, taste, smell, et cetera, but sense of self is different. Sense of self is really about what's going on internally within the
confines of our skin. And it involves two key features
that if you can understand those features, and you
understand what modulates or changes, our ability
to sense those features, there are a lot of things that you can do in terms of how you structure
your nutritional practices, how you relate to your exercise practices, perhaps even certain things
that you take in terms of supplementation that can
basically make you feel better, more alert, and more
capable for everything. I don't think that's a
hyperbolic statement, I, in fact, I know it's not a hyperbolic
statement because we have a system in our body that connects our brain to all of our bodily organs and connects all of those
bodily organs to our brain. And that communication
between brain and body in both directions creates a situation where either we are
positioned to do things well, or we are positioned to do things poorly. So I really want to dive in and dissect, what is this system of
brain, body communication? What does it look like? What are the actual
neurons and connections? And as I do that, I promise that I'm going
to place protocols, tools that you can apply
in order to make sure that those neurons and
connections are working optimally. So let's begin by talking about
what system communicates the brain to the body and the
body back to the brain. The system that's most often
associated with this is our 10th cranial nerve called the vagus nerve. The word vagus relates
to the word vagabond, which to wander, and indeed
the vagus nerve is a vast, enormous wandering set of
nerves, so it's not one nerve. It's not like one fiber, one axon. As we say in the nervous
system, we have these wires, we call axons that let
neurons communicate. It's a bunch of neurons and a bunch of wires that go everywhere,
so where do they go? Well they leave the
brain, and the brain stem, the brain stem is kind of
the back of your brain. If you touch the back of your neck, it's about three inches deep
to where you're touching. The neurons that are there send information into the body to control your bodily organs,
how fast your heart is, beating how fast you're breathing, how fast your digestion is occurring. Even things like whether
or not you are going to secrete so-called killer cells, your immune cells from your
spleen to go ward off bacteria. Now the neurons there don't
know what to do unless they receive information about
what's going on within the body and within the body, your heart,
your lungs, your diaphragm, your gut, so everything
from your intestines to your stomach, et cetera, and your spleen or sending
information also up to the brain. So as I mentioned before,
it's a two-way street. So the vagus nerve is
a very important nerve, but just by saying vagus nerve,
it sounds like a singular. It sounds like one thing, but actually what we're
talking about is a series of super highways, it's like Google maps, it's got stuff going everywhere with alternate routes,
communicating back and forth. There are two fundamental
features of what's going on in your body that
need to be communicated to your brain, these neurons
in your brain stem in order for your brain and your body
to work together correctly. And the two types of information
are mechanical information. So things like pressure, things like lack of pressure
and chemical information, whether or not your gut is acidic or whether or not it's not acidic, whether or not you have some
sort of pathogen, you know, something that you ate or that
got into your body somehow and is making you sick or whether or not you don't have a pathogen in your body. So you've got mechanical
sensing and chemical sensing. So when you think about your sense of self and your ability
to understand what's going on in your body, if you feel
good, or if you feel bad, your sense of self is
dependent on these mechanical phenomenon and these chemical phenomenon. And for every organ in your body, whether or not that's
your heart or your lungs or your spleen, both the
mechanical information about that organ for instance, is
if your gut is full or empty, whether or not your heart is
beating fast or beating slowly, that's mechanical, and
chemical information, whether or not your gut feels
nice, and whether, you know, when I say nice, I mean, whether or not it has a balance
of acidity and alkalinity, that feels right to you or
whether or not your gut feels off, it doesn't feel quite right. That's chemical information. If you are not getting enough oxygen and levels of carbon dioxide
and other gas go up too high. So your lungs can register that and that chemical
information is sent to your brain. And then your brain does
certain things actually really encourages you to do certain things in order to adjust that chemistry. So the first principle that
everyone should understand about their sense of self is that
they are sensing mechanical and chemical information about every organ in their body, except for
one, and that's the brain. Your brain actually doesn't
have pain receptors. It doesn't even have touch receptors. The brain is a command center. It helps drive and govern changes
in the organs of the body. But your brain doesn't
move, at least not much. It can move a little bit
fluid moves within it. But as long as you're healthy,
it's not moving that much. Your brain has no sensation of its own, in fact, when they
do brain surgery on people, they will the size or put
some anesthesia on the scalp. They'll cut away the skin there so that people don't feel anything. They'll use some anesthesia
they'll peel back the skin and then they'll use a, let's call it what it is, it's a bone saw. And they basically saw open
a little window in the skull. I've actually done this
before and seen this before. I've done this many times before, and once you're inside the brain, you can put electrodes in
there and you can put various things in there, of course,
all for therapeutic purposes. And you do that without any
anesthesia to the actual brain tissue, because it has no
receptors to sense anything. It doesn't have pain receptors. It doesn't have pressure receptors. None of that, when you have a headache in your head, feels like
it's too much pressure, well that's because of here's
that lie outside the brain. So your organs are different. They need to tell your
brain what's going on. And there are ways that you
can control the mechanical and the chemical state of your organs in ways that are very
powerful, and this is crucial to do, because if you can
properly regulate the mechanical and chemical environment of your body, your brain functions better. This is absolutely clear from data that if your gut is healthy, if you get the alkalinity
right, the acidity, right, and if your spleen is healthy and happy, and if your
lungs are working properly, not just breathing and
pumping in and out air, but you're breathing at the
right cadence for a particular activity, then your brain
will function better. So let's talk about how you
can adjust the mechanical and chemical environment of your organs in order to make your brain better and how your brain can make the mechanical and chemical environment within
your organs function better. For instance we're going to talk about how you can change the
chemistry of your gut in order for your brain to be able to
focus better, think better, remember better and sleep better. And we're going to talk
about how you can change the chemistry of other
organs in your body, such that your immune
system will function better than it would otherwise. And you can actually heal
faster from small cuts and bruises, but also injuries of
any kind, even major injuries. So as I mentioned before,
we've got these organs, the heart, the lungs, the diaphragm, and I'll explain what that
is, the gut and the spleen. And the spleen is this immune organ. Let's take one example of these
and explain how mechanical and chemical information
from this particular set of organs communicates to the brain and how that changes how our brain works. And the organ I'd like to focus on first are the lungs and the diaphragm. So we're all familiar with
our lungs, these two big bags of air, but they're actually
not two big bags of air. They actually have little
tiny sacs within them, actually millions of little sacs called the alveoli of the lungs. The alveoli of the lungs are like little tiny balloons
throughout our lungs, and the more of those balloons, we have, the more air that we can actually contain. So we are not too big bags
of air in there, our lungs, we actually have millions and
millions of little tiny bags of air within those lungs. Those little bags of air can
fill up or they can deflate, right, just like your
lungs overall can fill up or they can deflate. The diaphragm is a muscle, it's
kind of shaped like a dome. So it's kind of a, you know, think about a basketball or a soccer ball that has most of the air pushed out of it. And so it's kind of crescent
shape or dome shaped, and it sits below our lungs
and the way the diaphragm and the lungs work together
is very interesting. The diaphragm is actually
skeletal muscles. So it's just like a bicep or a quadricep. And the fact that it is
skeletal muscle is important because it has a unique property, which is that you can
control it voluntarily. You can decide to take control of your diaphragm by just
consciously deciding you want to breathe in a particular way, just like you can take conscious
control over your legs. They will work just fine,
if you're not thinking about them, as you walk as
provide, you already know how to walk, but at any moment, you can decide to change the rate of your walking, your
so-called cadence of walking. So the diaphragm as a
skeletal muscle also has that property, the diaphragm moves up and down, depending on how you breathe, or rather, I should say
how the diaphragm moves up and down determines how you breathe. How you breathe is also dependent
on little muscles that are between your ribs, the
intercostals and other muscles, if you're a martial arts fan
that Bruce Lee was famous for having these very pronounced
intercostals from doing all sorts of, you know, bridging
exercise, et cetera. But those are the muscles. And we all have them, even if some of us, most of us don't have,
intercostals like Bruce Lee. So when you breathe a
couple things happen, but let's talk about the
mechanical things first. And then let's talk about how
those mechanical steps relate back to the brain and what
that does for the brain. And I can promise you that if you develop an awareness
of these mechanical changes, you do not have to go through
extensive breathwork practice or do extensive breathwork. You will immediately believe
it or not develop a sense of your breathing self of
your lungs and diaphragm. It takes no practice, but once you do it, you will forever be changed
in terms of your awareness of your breathing and your ability
to leverage your breathing. Kind of like the steering
wheel on a car in order to shift your brain in the
direction that you want to go. So it's a very powerful system. And the way it works is the following. And this will also
incorporate the heart, so, and by the heart, I don't mean
it in the emotional sense. Although we don't rule out emotions here at the Huberman Lab
podcast, we like emotions, but I'm talking about the heart as an organ, as a beating
organ, that circulates blood. So when we inhale, these little
sacs in our lungs fill up and our lungs expand. And when we do that, we take
up space in our thoracic cavity and our diaphragm moves down, okay. When we exhale, the diaphragm moves up, the lungs get smaller, okay? So inhales, diaphragm moves down. Exhales, diaphragm moves up. This actually controls our heart rate, but it does it by changing
the way that our brain works. And it works in the following way. So when we inhale, our lungs
fill our diaphragm moves down. Our heart actually has a little more space because the diaphragm's moved down. So the heart gets a little
bit bigger, physically bigger, not in the emotional sense,
but physically bigger. And as a consequence, whatever blood is in the
heart flows at a slower rate because it's a larger volume,
so bigger volume heart, same amount of blood inside
the heart means slower flow. Okay, sort of like expanding a pipe. The brain registers that
because there are a set of neurons in the heart
called the sinoatrial node. It sends that information to the brain. That information is registered
by the brain and the brain sends a message back to the
heart to speed the heart up. So every time you inhale because
of these mechanical changes in the diaphragm and lungs, and because of the mechanical
changes in the heart, your brain sends a signal to
the heart to speed the heart up, so if you do long inhales
or you inhale more vigorously, you actually are speeding your heart up. Now, of course you have to exhale as well. But for instance, if I were
to inhale very long like [inhales heavily] the entire time my heart
rate is increasing. And then if I did a quick exhale, [exhales quickly] something else will happen,
but if I kept doing that, [inhales heavily, exhales quickly] my heart rate would increase. It's not going to increase
linearly and forever, but it will increase with each inhale. Or I can simply make my
inhales more vigorous. [inhales quickly] And my heart rate will speed up. This is an autonomic and
automatic relationship between the diaphragm, the
lungs, the brain, and the heart. Now, if inhale speed the heart
up, what happens on exhales? When we exhale, the diaphragm moves up. It's a little counterintuitive, but you can kind of think about it as like pushing the plunge
on a syringe, right? When you exhale, this thing moves up and
as the diaphragm moves up, the heart has less space. Meaning it gets a little bit smaller, which means that whatever
volume of blood is inside the heart moves faster, through
that smaller volume, that information is sent to
the brain via these collection of neurons called the sinoatrial
node for you aficionados. The brain then sends information
via the vagus nerve back to the heart, to slow the heart down. So while inhales speed up the heart, that's the net effect
exhales, slow the heart down. And the reason they slow the heart down is because of a register in the
change in mechanical pressure between the diaphragm,
the lungs and the heart. So this is to me, the simplest and most straightforward example of how the brain is changing
the way our organs work, our heart in this case, according to changes in
mechanical interoception. Now, we're not always aware
of this, some of us are aware of it, some of us aren't. If you do it right now, you will be aware of
it, so you can try this. You can basically, this is an experiment or an example in interoception,
in sensing one's self. So if you inhale, doesn't
matter how long you inhale. I'll do it for a couple seconds [inhales quickly] and then exhale twice as long. [exhales slowly] Nose or mouth, doesn't
matter, the entire time that you're exhaling, you're
slowing your heart down. So just as a car has an
accelerator and a brake, or you can slow a car by
coming off the accelerator. When you exhale, you're effectively coming
off the accelerator, or if you want to think
about it differently, you're hitting the brake, you're slowing down your heart rate. Now, normally your heart
rate stays in more or less the same range for a given activity because you're inhaling and exhaling. But this is just a simple way of showing that mechanical changes in
your viscera can change the way that your brain works and then your brain changes the
way that those viscera work. And it's a very concrete agreement, it's like a contract between the organs of your body and the brain. In fact, you can think about
this contract in more detail, and you can leverage this
in a very powerful way to set the conditions of your mind. If you want to be more
calm, emphasize exhales, and the simplest way to do this. I've talked about this many times before, but if you haven't heard me say it, this will become immediately clear is to emphasize exhales through what's called a physiological sigh. Two inhales, could be through
the nose of the mouth, but ideally through the nose,
so [inhales quickly twice] so followed by a long
exhale. [exhales slowly] Those double inhales are
kind of important because what they do is they maximally
fill all those little sacs in your lungs, and then
when you breathe out, you're exhaling as much of
the so-called carbon dioxide in your system as possible. We'll talk about carbon oxide in a second. So the fastest way to calm
down is to emphasize exhales. When you make exhales longer, you're slowing your heart
rate, you're calming down. You don't need any sophisticated training. You don't have to do
this for minutes on end. You don't have to do anything. You don't even have to call it breathwork. It's just respiration, and in
fact, you do this every night. When you go to sleep and carbon
dioxide builds up too much in your bloodstream, or if you hold your breath or something, or you watch an animal or a
small child that sleeping, they will occasionally do these
double inhale long exhales it's way of slowing the heart down and eliminating carbon oxide. The opposite is also true. If you inhale deeply or vigorously and then exhale less
long or less vigorously, you will increase your level
of alertness through these purely mechanical aspects
of your interoception. So for instance, if I were
to take a big deep inhale [inhales deeply] and then a short exhale, [exhales quickly] and then
another one, a big inhale, [inhales deeply] short
exhale, [exhales quickly] It only takes two or three of those before you start to feel more alert. And that's because your
heart rate is increasing. And actually if you keep doing that for 25 or 30 breaths of
inhale deep short exhale, you will start to secrete
a lot of adrenaline. This hormone that comes from your kidneys and from your brainstem
make you feel really alert. You will actually feel as if
you've had a cup of espresso. So you will immediately wake up. And there's an intermediate form of breathing, which is
sometimes called box breathing, but it's really equal
inhale and exhale duration. And these, it basically goes like this. You're you're going to inhale,
so do this for maybe two, three seconds inhale, [inhales] then hold, okay, two, three seconds. Then exhale, two, three seconds. Then hold two, three seconds. Most often people forget to hold. So it's inhale, hold, exhale, hold for equal or more or less equal durations, could be one second, could be two seconds, could be three seconds. Most people find that when you get out past five seconds,
they start to struggle to maintain the so-called box breathing. And most people can't
consciously box breathe for too terribly long without
having to think about it. But the point here is that
through purely mechanical means changing the way that you
breathe, emphasizing inhales or exhales, or keeping them the same will change the way that your brain works, how alert you are and how
well you function in anything. And again, this doesn't mean
that breathwork has no value. It's just simply to say
that long extended protocols of breathwork are simply, they are truly simply just
an exploration of this fundamental relationship
between the mechanics of your internal organs and your brain and how your brain controls
those internal organs. Now you might ask, well,
how is this pressure known? How does the body actually know
how full the lungs are, now? This is an answer that's more
for the aficionados out there, but I've had a few requests, or I should say thousands of
requests for more in-depth science, so if you're not
interested more in depth science, just this will allow you to
tune out now for maybe just 10 seconds, and if you are
interested, pay careful attention, there is a set of receptors which are called piezo receptors, P-I-E-Z-O piezo receptors,
piezo means pressure. And these were discovered
a few years ago by a couple of different laboratories,
but one of the main ones, one of the main laboratories that discovered these piezo receptors is the laboratory of Ardem Patapoutian. I love saying his name, even though I'm probably pronouncing it, he's a friend and a former
colleague when my lab was down in San Diego, he's at
the Scripps Institute, he's a Howard Hughes Medical
Institute investigator, which basically means
that he's a total stud of science and has made
many important discoveries. The piezo receptors line many tissues, and inform the brain about
pressure in those tissues. But the lungs have a particular category of piezo receptors called
piezo two receptors. And as you fill your lungs
and these little sacs of air, the alveoli fill,
the piezo two receptors because of the way they
react to that filling send information by way
of a bunch of neurons, a bunch of wires up to the
brain and tell you how full your lungs are, so that's the
kind of mechanistic detail. If you want to learn more about that, you can look up our
Ardem's lab at the Scripps and the beautiful work that
they and other laboratories are doing on piezos,
piezos are pretty cool. I think I also just like saying piezo, so that's why I brought that up as well. So mechanical sensing of the
lungs, heart and diaphragm. And now let's talk about chemical sensing because there's carbon
dioxide and there's oxygen. And this is really simple. You have oxygen and carbon
dioxide and you need them both. I sometimes hear people
talk about carbon dioxide is this bad thing and
oxygen, it has a good thing. You need them both, and you need them in
the appropriate balance. You have a collection of neurons
in your brain that register when carbon dioxide levels
get to a certain point in your bloodstream. When that point, that
threshold is reached, these neurons fire, and they cause you to
breathe sometimes called the gasp reflex, it just
makes you want to inhale. And as a consequence,
you bring in more oxygen. Okay, so we don't really
breathe to get oxygen. That's a by-product of inhaling
to eliminate carbon dioxide. You don't want carbon dioxide
levels to go too high. In fact, if you want to freak
somebody out and we do these in experiments, and I don't
recommend you do this, you just increase the levels
of carbon dioxide that they inhale, and the brain will go
into an almost immediate panic response because the health
of all our tissues depends on keeping a nice balance between
carbon dioxide and oxygen. You don't want carbon dioxide
levels to go too high. So the impulse to breathe,
if you're under water, or if you hold your breath is triggered by these neurons and the
triggering of those neurons comes from elevated carbon
dioxide in the bloodstream. And for those of you that don't quite know how to conceptualize the relationship between bloodstream and breath, I do think it's important. And maybe you remember this
from high school biology, but if you don't, I'll make it clear for
you now, it's very easy. You inhale air and that air
and the oxygen molecules in that air actually move from your lungs into the bloodstream because these little alveoli of the lungs, those little sacs of air are in there, they basically have a lot
of little micro vessels and capillaries, little tiny,
basically blood vessels, essentially, although
they're mostly capillaries, micro capillaries are
the little tiny ones, that line them, so there's actually an interface and opportunity for air and molecules within the
air to pass into the blood and then they move in your
bloodstream, and when you exhale, the opposite is true. So you can move things from the air, into your bloodstream or from
your bloodstream into the air by way of the lungs, and
there's a lot more detail to it. And I'm sure those of you
that are experts out there. If you want to put some
stuff in the comments, maybe a little bit of a kind
of intermediate tutorial, you might even entitle
it, intermediate tutorial. If you know a lot about
this, just I'll check it, but make sure you get the details, right. Make sure you know the process. And I find that for
people that are interested in understanding how
breathing really works, it's really nice to think
about the relationship between the heart and the vascular system, the blood and the air system,
the respiration system, and breathing, because those
two things are very, we say, they're interdigitated, they're
interwoven with one another. So how does this work, well,
carbon dioxide is too high, you breathe in, you inspire, you, inhale you off as a consequence, when you exhale, you
offload carbon dioxide. There's a really cool way
that you can explore this chemistry of your breathing
and your bloodstream and the way that your brain works in ways that can really
benefit your health. And it works the following way. You want to essentially sit or lie down. It doesn't really matter. You definitely don't want
to be anywhere near water, not a bathtub, not a hot
tub, not a, you know, not a cold dunk or something. In fact, don't even be in a puddle. And what you want to do in this case is you're
going to breathe in deep. So that's going to increase
your heart rate and then exhale passively by just letting
air fall out of your mouth. So it will look something like this. [inhales vigorously, exhales passively] So it's you breathe in vigorously and then you let the air
just fall out of your mouth. When you do that, what you're essentially
doing is you're bringing in a lot of oxygen
through that deep breath. And you're exhaling a little
bit of that carbon dioxide. But if you were to repeat
it 25 times, maybe 30 times, it doesn't matter if it's 25
or 30, somewhere in there, you would essentially start
bringing in a lot of oxygen and blowing off or exhaling
a lot of carbon dioxide. So you're actually going
to change the chemistry of your internal landscape,
and you can then sense it. You can interocept what that is like. And there are some really
interesting reasons for wanting to do that, so
I'm not going to do all 25 or 30 now, maybe do five or 10, so you can get a sense
of what it looks like, so that it's clear. I'm going to essentially
demonstrate now, so it's inhale, [inhales vigorously] exhale through the mouth,[exhales]
I am inhaling the nose, [inhales vigorously, exhales
passively multiple times] So it's essentially, excuse
me, a two second or so inhale and then a one second or so
exhale, and as I was doing that, I can kind of feel my face get
flush and my body is heating up and my brain is heating
up, what's happening there? Well that pattern of breathing is increasing levels of adrenaline in my brain and body, and
I'm getting more alert. Then after 25 or 30 of those,
you exhale all your air. [exhales deeply] You dump all your air. You can do that, your nose or your mouth. And then you hold your
breath with your lungs empty for about 15 to 30 seconds. Now, for those of you that want to explore this, and please be
careful as you explore this, don't do anything stupid, like do this while you're
driving or something like that. You can exhale all your air and what you'll find then
is you can hold your breath for a very long time. And the reason you can do that
is because you've blown off all the carbon dioxide or
most of the carbon dioxide in your bloodstream. So you shifted the chemistry of your blood by breathing in a particular way. And by doing that, you are no longer triggering these neurons that cause the gasp reflex
or the reflex to breathe. Now, of course you have
to breathe sooner or later but what you'll find is if
normally your ability to hold your breath is a minute or
so before you really feel that gasp reflex kick in, you might find that you can
go 90 seconds or two minutes. And with some practice, people find that they can
start holding their breath for three or four minutes or longer. This is actually how free
divers do what they do. I do not want anyone free diving. If you're going to learn free diving, please learn it from an expert. Many people die trying to teach
themselves out of free dive or trying to teach their
friends at a free dive when they don't know what they're doing. This is not what this
is about, don't again, don't do this anywhere near water, but it is a very interesting
exploration of how you can shift the chemistry of your
bloodstream by modulating your air by modulating the mechanics
of your diaphragm and lungs and thereby shift the way
your mind works, your brain. And in fact, what you'll
notice is that even though during that 25 or 30 breaths, [inhales and exhales quickly] you'll feel very alert,
when you exhale all your air and you're in the breath hold,
you will feel very alert, but very calm. Now this is interesting because it's a state that we all sort of want to achieve alert, but calm, but have a hard time achieving. And so for those of you that
have a hard time obtaining focus for sake of work or
focus for sake of anything I should say, and when you
are able to achieve focus, it's through the use of
things like stimulants, or you feel like you have
to have a cold shower or ice bath, or you have to
have four espresso in order to be alert, but then you're
too alert, you're jittery. You can't focus. This pattern of breathing
can lend itself very well to entering states of alert,
but calm for the fall, the 10 or even 20 minutes
that follow that breathing. And then you could repeat it if you want. So it's a very useful practice to explore. Some of you may be familiar with this practice and
so-called Wim Hof breathing. Wim Hof is a practitioner of
what's called Tumo breathing. Tumo breathing has been
around for centuries. And for those of you that are familiar with breathwork and yoga practices, I acknowledged that nothing
I just described is new based on science, however, the science informs why
those practices work. And just as a little mini editorial, I just want to emphasize as well. That one thing that this podcast
is really about is trying to remove fancy nomenclature, whether or not it's yogic nomenclature
or scientific nomenclature so that people can access protocols. Because the moment we start
naming things after people or calling them Tumo et cetera,
I have no problem with that, but it doesn't inform how
the practices are done, nor does it inform the
underlying mechanisms. So here I'm trying to
teach you the mechanisms. And as a final point to that, the most powerful form
of breathing is the one that takes into account the fundamental mechanisms
that in increase heart rate, that exhales decrease heart
rate, and that carbon dioxide and oxygen relate to the
bloodstream and the brain in particular ways, once you
understand those components, then you can create your own
so-called breathwork practices. You can breathe in the
ways that best serve you, as opposed to thinking that
one protocol is the best or holy protocol for everything,
because it's simply not. As a final final point, I want to say that as you
shift the way that you breathe, whether or not you're showing
off more carbon dioxide or bringing in more oxygen, you are fundamentally
changing the chemistry of your internal milieu have your body, and that has been shown
to have important effects on the way that your immune
system functions and the way that you deal with
inflammation and all sorts of different sort of things
that can enter your body and cause problems or
conditions of stress, et cetera. So I will explore that further
as the episode goes on, but I want to move on to just
touch on one other aspect of reading, that's purely mechanical, which I think is very interesting and important, which relates
to a particular reflex that you're going to be very
familiar with in a second. And that can serve you very
well in times of extreme stress. The reflex I'm referring to is something called the
Hering Breuer Reflex. I'm not going to go into details about how the Hering Breuer reflex works, but it has to do with particular classes of neurons and cells that
are called a Baroreceptors. Those are basically pressure
receptors, they sense pressure. And basically what the
Hering Breuer reflex is about is that when your lung is inflated, your desire to breathe is reduced. So you can try that
right now, you can inhale [inhales] huge big thing of air. And hold, okay? Your desire to breathe
will kick in later than were are you to exhale all
your air and hold your breath. When you exhale all your
air and your breath, unless you've done the sort
of protocol I described a few minutes ago of doing a bunch
of inhales and exhales first in a very deliberate
way, you will feel empty. Those Baroreceptors are
going to be firing like crazy saying, there's no pressure in here, there's no pressure here,
I got nothing in here. You need to breathe,
you need to breathe in, the gasp reflex will kick in sooner. You can apply that in all
sorts of situations related to exercise, related to
modulating stress, et cetera. So the Hering Breuer reflex
is a very powerful one. This is why you take a big deep breath before you go under
water. [inhales heavily] All right, you're not going to exhale all your air and go under water. If you were to exhale all
your air and go under water, you would absolutely feel
the need to come up sooner for a breath of air than
had you a full tank, so to speak a full of lungs full of air. And this is also the way
that people teach themselves to feel comfortable under water. So when you learn how to swim, you learn how to swim both by having air in your lungs while you're
underwater and no air in your lungs while you're underwater. In any event the Hering
Breuer reflex is yet another dimension to the way that
mechanical pressure influences your brain's decision-making,
about what to do with your body, in this case,
whether or not to breathe. So now I want to shift away from breathing and diaphragm and lungs and
move toward another organ within our viscera, which is our gut. So this includes our stomach and our intestines, our
esophagus and so forth. It's been said before,
both by me and by others that we are, but a series of
tubes, and indeed that's true. Believe it or not, every
system in your body is a tube. Your brain is actually a tube
that connects your spinal cord, which has also a tube. You started off as a tube,
you were like a churro. You know, those churros I don't know if you're
not familiar with churros, they're like donuts that
are shaped like a tube. That's essentially what you
look like early in development, not long after conception
and the front end of that churro grew and grew and grew, but you always maintained
a hollow through that tube. That's why you have what are
called ventricles, gaps or a space in your brain and spinal
cord that run the length of your brain and spinal cord and fluid, cerebral spinal fluid, and other things move through that space. We're going to return
to the ventricles later, they are very important. They're just space filled
with fluid, but they do a lot. Similarly your digestive system starts with the tube at your mouth and of course goes down
through your throat. And then you've got all
the elements of the stomach and the intestines, and then
it comes out the other end. So you are, but a series
of different tubes, your vascular system, a
series of other tubes. So you're tubes. The way your digestive system works is to communicate to your brain about the status of the
mechanical pressures along this tube, so within your stomach and your intestines, et cetera, and the chemical status of
that tube at various portions within that tube to inform your brain about how your brain
should control that tube. So let's start with the
mechanical sensing of your gut. If you drink a lot of fluid,
or if you eat a lot of food, your gut will fill up, your
stomach will fill up with food. Now it gets digested there. It gets digested elsewhere
along your digestive track too, of course but it starts
getting digested there because along this tube, you have a series of what
are called sphincters, which basically are
like little draw pulls. Have you ever had a laundry bag, which has a drawstring on it? You pull it and then it cinches shut, and then you can open it
again, that's what those are. Those are sphincter
openings and you have them in your throat, you have them
along your digestive tract, all the way to the end. Food will enter your gut. And if there's a lot of that
food, pressure receptors, some of which are these
piezo receptors will communicate to the areas of
your brain that are involved in feeding, and we'll
say, don't eat anymore. You don't need to consume anymore, now, some people bypass that these, I guess they have these like
hotdog eating competitions. I'm always struck by how some
of those people are like, seem to be rail thin, but they actually train for
those competitions by ingesting large volumes of water, actually
a very dangerous practice. You can actually kill yourself
by drinking too much water, and you can kill yourself by
ingesting too much of anything, really to expand your
gut, not a good practice, not a big fan of those competitions. But even if you're one of those
people or you're the world heavyweight champion of them, they are informative
toward what I'm talking about now, which is that
as you expand the gut, a signal is sent by neurons, literally nerve cells that
are in the gut to the brain, stem up to the areas of
the brain that are involved in feeding, I did a
whole episode on feeding. You can find on "Feeding,
Metabolism And Hunger." You're welcome to listen to
that episode, if you like, and we'll shut down the
neurons that drive the desire to put more stuff in your mouth. That thing that people say sometimes on well in this country frequently
after Thanksgiving meal, I can't put another bite in my mouth. Literally they shut down
some of the basic movements of the musculature to
take another fork bite. I know it sounds crazy, but they can actually control your brain. So your gut is so full that
it's controlling your brains, such that this action of spooning food towards your mouth is actually inhibited. It's made more difficult
or less likely to occur. It's incredible. The converse is also true, when
these piezo receptors signal to the brain, that the
gut is empty independent of your need, your actual need for food. There's a signal that sent to
your brain that says gut is empty and neurons get stimulated
in areas like the arcuate nucleus and these areas
of the hypothalamus and et cetera, that drive the
desire to make this action, to open the mouth and to put
stuff in it in particular food. So when you find yourself
at the refrigerator or you find yourself almost, you know, manically trying to get
food of different cons, you're not even thinking
about what you're eating, because you're so hungry, in
part that's because the lack of food in your gut has sent
that information to your brain and is driving particular
fixed action patterns that are associated with eating, in fact, one of the first things
children learn how to do is open their mouth when something
is presented to it. And then they learn how
to move a spoon or a fork. They're not very good at
it, at first, they get all over the place, but
eventually they get good at, or at least most people get good at if you watch how people eat, you know, it's kind of very variable out there. In any event, this is a
purely mechanical phenomenon. And this purely mechanical
phenomenon is driving our brain to drive certain behavior. You can get better at registering sense of fullness or lack of fullness
in a very particular way. Some people have a very
keen sense of how full or empty their stomach is,
so if you've eaten anything, even if it's a small volume
of food in the last hour to three hours, it's actually a worthwhile
practice to take a few moments, maybe 10, 20 seconds, and actually just try and
concentrate on sensing the neurons in your gut and how full
you are, like for instance, I ate a few hours ago and
then I had a little snack about 30 minutes ago or so. And my gut feels neither
terribly full nor terribly empty. It's kind of, I would put it
kind of like 30, 40% okay. So by just taking conscious awareness of how full or empty our gut is at various times between
meals, after a meal, before a meal, you can very
quickly develop a sense of how full or empty you are. Now, what's the consequence of that? The consequence of that is
actually rather interesting. It's been shown that the consequence of that is actually that you can
better override the signals of these piezo receptors and
gut fullness or emptiness. So for those of you that
find that you eat kind of compulsively or non-consciously, or subconsciously, I should say, probably have to be conscious
enough to be awake to eat, but subconsciously you
just find yourself eating and here I'm describing myself, I'm like, I'm a drive by blueberry eater. If there's a bowl of blueberries,
every time I walk past it, I sort of have to grab a handful of them and pop them in my mouth,
but if you develop this sense of how much mecho-pressure,
it's not really word, but how much mechano-sensation
is in your gut, very quickly, you can learn to override that. You might ask, why would I
want to be able to override whether or not my stomach is
empty or my stomach is full? Well, there are many
reasons to want to do that. Many people right now are interested in so-called intermittent fasting. They're doing fast of
anywhere from 12 to 16 hours, every 24 hour cycle, that's
actually what my practice is. I do that on a regular
basis, sometimes the, I eat breakfast, but normally I pushed breakfast
out to about 11 or noon, or sometimes a little later, some people are doing longer fast, and there are really wonderful data publishing excellent
journals from my colleagues Satchin Panda at the Salk
Institute Of Biological Studies. And of course from other
laboratories showing that intermittent fasting can and
will have some positive health effects on things like liver health and brain health and
other aspects of health. Whether or not it's the
best form of dieting for the sake of losing weight,
that's very controversial, but it's clear that having
a period of fasting every 24 hours or perhaps even longer
from time to time can be beneficial because it stimulates
what's called autophagy, the clearing away, or the body's ability to
eat certain dead cells, so called senescent cells,
and for many people, they struggle with fasting
because they feel they have a very keen sense of their
stomach being empty. And they feel as if they have to eat. And in a kind of counter-intuitive way, there's some data that
indicate that being able to sense whether or not
your gut is full or empty, and just the knowledge that
that's communicating information to your brain about whether to not to eat or not just that awareness, that understanding allows
them to override the signal. They think, oh, you know, I'm not actually in need
of nutrients right now. It's just that my stomach is empty. And these piezo receptors, and some other ones that I'll
tell you about in a moment are signaling to my brain that it's empty. I don't actually need food, it's just, it's just that my brain is reacting to the fact that my gut is deflated, so to speak or a smaller,
doesn't have food in it. So there are other ways that
our guts communicate with our brain, it's not just our
stomach talking to our brain. It's also our intestines
talk to our brain. The Liberles Lab the guy's
name is Steven Liberles, he runs a lab at Harvard Medical School, it's a terrific lab, does excellent work on gut, brain communication and other aspects of
viscera brain communication. They discovered a category of neurons called the GLP1R neurons, these are neurons that are basically in your neck, I mean, they're
part of the nervous system, but they're, you can, they
can be found near your neck. And those neurons send little wires down into the intestines and
deep into the stomach, but mostly into the intestines
and they sense stretch of your intestines. So this is pretty wild. These neurons sense how
stretched out your intestines are and how fast things are moving
through your intestines, slow or fast, or if there's nothing there. And then those neurons
send another branch, they have a branch in one direction, senses what's going on in your intestines. And they have another branch that goes up from your neck in your brain
to either trigger the desire to eat more or just stop eating. So these are really cool neurons and they're basically stretch receptors. They look a lot like the piezo receptors that we talked about before,
so these GLP1R neurons are sensing stretch, so
purely mechanical sensing. And in addition to that, the Liberles Lab discovered neurons that detect nutrients themselves. Now, the main reason why we need to eat is to bring
nutrients into our body. And there is another set of neurons, those are called GPR65 neurons, if you want to know, but you
don't have to remember that, do the same thing in terms
of their connections. They send connections down into
the intestines and into the gut, into the stomach, but
mostly into the intestines. And then send that information back up to the brain as to whether or
not there are certain kinds of nutrients in our digestive track. Now, these neurons are the
ones to pay attention to if we're talking about chemical signaling and then in the next couple of minutes, I'm going to tell you about
how you can understand hunger and had a modulate your
hunger for the right foods, in fact, for healthy foods. The way this is done is
by leveraging the activity of these GPR65 neurons, these neurons that sense nutrients, okay. They're telling your brain what's in your gut and intestines, and you have another set of
neurons that were discovered by another guy he's
out at Duke University, his name is Diego, excuse me, Diego Borges he's a wonderful scientist. He has a degree in nutrition,
but also in neuroscience. And he found that there are
neurons that line the gut, and those neurons in
collaboration with these GPR65 neurons are sensing
for three things, okay? So we say nutrients, which
nutrients are they looking for? What are these neurons
paying attention to? While these neurons are
activated by the presence of fatty acids in particular,
omega-3 fatty acids, sorts of things that come
from fatty fish, oil, krill, certain kinds of animal protein, animal, and plant substances. You can look up what has a
lot of omega-3s and those omega-3s make these neurons
fire electrically like crazy up to the brain and make you
want to eat more of those things, but it turns out in
pretty appropriate levels. These neurons also respond to amino acids. So when you eat a food,
it's broken down in the gut, actually the way it's
broken down in the gut is kind of interesting. Your gut basically cinches
off a sphincter up top, cinches off a sphincter below
it when there's food there. And then you have a
series of smooth muscles that tumble the food and literally
physically break it down. And then of course, enzymes come in and
start digesting the food. And we're going to talk about digestion and how that's communicated
to the brain in a moment. And for those of you with any
autoimmune issues or digestive issues, this is going to be
very important conversation. But meanwhile there are these neurons in the gut and as these fatty acids float out of the digested food, so literally fat molecules,
and as amino acids are coming from the proteins as
they're digested in the gut. And as a third food item, sugars are coming from
the foods that we eat. These neurons will fire a lot
to the brain that says, Hey, whatever you're doing up
there, do more of it, okay? Now the sugars are a
little bit cryptic because when I say sugars or I say amino acids, or I say fatty acids, this
has nothing to do with taste. In fact, beautiful
experiments have been done by the Borges Lab and
by other labs showing that even if you numb the mouth, even if you gavavge,
which is a really, just a, it's a fancy word for
basically tube feeding, you put a tube down into the gut, you just deliver the food to the gut. So you get no opportunity to
taste, it sounds pretty awful. If you force feed by gavage,
or you numb the mouth, these neurons don't care about the mouth. They only care about the
nutrients coming from these foods. And then they signal to the
brain, hey, do that thing, do that thing where you lift
that object, we call a fork or a spoon, do that thing
where you drink the milkshake, do that thing where you
move your mouth like this, not talking, but do that
thing where you swallow. So that's how the nutrients
in our gut control us. And this is why for people
that experience extreme sugar cravings, or even mild sugar cravings, replacing those foods with
foods that have high levels of omega-3 or amino acids
can produce sugar cravings. And I've talked about this
on a previous episode, but if you didn't catch it, no big deal. I'll tell you right now
that for many people, the solution to sugar cravings
is to ingest a small amount, maybe a teaspoon or so of an
amino acid called glutamine. And if you have really
extreme sugar cravings, you can even mix that glutamine
with a full-fat cream, which actually makes it
taste pretty darn good. And you drink that anytime
you have a sugar craving or just a sip or two of that. And we find is that the
sugar cravings disappear, because you're basically
giving fat and amino acids to those neurons in the
gut and in the intestine, that signal to the brain
that you want more. Now, this doesn't give you a kind of runaway hunger for full fat cream. Although it will say when I
was in high school for various reasons, but mostly because
I liked the way it tastes. I was using half and half in my cereal. And I was waking up in the
middle of night and drinking half and half, and that stuff
tastes pretty darn good once you get used to the high fat content. Not something I do now. But the point is these neurons
don't really know taste, they only know nutrients. And so you can work with that
system if you crave sugar, and I do believe that most if
not all of us should be trying to limit, if not eliminate simple sugars, as much as possible most of the time, then things like glutamine,
things like high omega-3 foods, et cetera, maybe even want to supplement with fish oil or something
similar to get omega-3s, there are other reasons for wanting to do that too,
can be very beneficial. And here's what we're talking
about is interoception, it's your ability to sense
your inner real estate, but in this case, by way of chemical signaling, not by
way of mechanical signaling. So now I'd like to talk
about another aspect of gut chemistry that has profound effects on the brain, as well
as on the immune system. And for those of you with
auto-immune conditions, or for those of you that
know people with auto-immune conditions, this is going to
be a very important discussion. Your gut needs to maintain
a certain level of acidity or alkalinity, for those of
you without any chemistry background, basically the
low numbers on the pH scale, that means more acidic,
the higher, the numbers, more alkaline, so more
alkaline means more basic and acidic means acidic. And it has to do with whom
hydrogen atoms and all this other stuff, but you don't need to
worry about that right now. We're not going to pH your gut right now, but we are going to talk
about the pH of your gut. Your gut needs to be more acidic
than essentially all other tissues of your body in
order to function properly, bacteria thrive in alkaline conditions. I think this is important
for people to understand. People are always thinking, oh, you should be more alkaline being acidic, that almost sounds like being
inflamed at well, you know, it's a complicated discussion, but I think the semantics
can be confusing, sometimes you want your gut to be acidic. You may ask, well, why are
people taking antacids? Well, those antacids are
there for a particular purpose to essentially combat acid reflux, which is the sending up of stuff in the gut towards the esophagus. And it can cause heartburn
and things of that sort. And the way the antacids
work is they essentially cause the sphincters above the gut to sinch shut, but they
really are only dealing with a symptom, not the cause. So rewind, and about 10, 20 years ago, the discussion about gut acidity
was quite a bit different than it is now in the scientific
and medical literature. In fact, for many years long before, I'm going to say it here,
people have been saying that it's important to
maintain proper acidity of the gut, but the science
and medical professions sort of looked at that as kind
of a scance like, you know, what's going on there, I don't, I don't know that there's any
evidence that that's actually true, there are communities of
people that were prescribing, or I should say recommending
that people take hydrochloric acid HCL and adjusting
gut acidity that way. And it was kind of frowned upon, now in looking over the
peer reviewed literature, it's clear that this business
of trying to make the gut a little more acidic is actually one way in which people treat or try
and ameliorate acid reflux. So it's kind of counterintuitive
increasing acidity in the gut to try and reduce acid
reflux, thought you're supposed to take antacids, well, the
field has shifted quite a bit. And so we're going to review
what it is to maintain the chemistry of the gut at a
slightly more acidic level or a more aesthetic level, I should say, because it turns out
that there are a number of things that are in gut
are just call it what it is, it's gastric juice, sounds kind of gross. But gastric juices are actually powerful modulators of brain state. Put differently, one of the best things that you can do to have a healthy brain, a well-functioning brain and a healthy and well-functioning body is to maintain proper gut chemistry. And that's basically accomplished
by getting the right level of acidity and alkalinity in your gut. Now this is not quack pseudoscience. This is not based on cleanses
or anything of that sort. Well, we're going to talk about
now are peer reviewed data in very high quality journals,
like the Journal Cell, which is one of the three
apex science nature, so, and journals of that sort, that point to the gut
microbiome and its relationship to acidity of the gut and how
the gut microbiome can help enhance auto-immune function and various other aspects
of brain and body health. So within all the mucosal
lining tissues of our body, we have what are called
microbiota, little micro organisms that we didn't make that actually come from our environment or our
food and live inside us. And there are good microbiota
and there are bad microbiota whether or not we have good microbiota or bad microbiota depends on one thing. And that one thing is how acid or alkaline the given mucosal tissue is. So we actually have a
microbiome in our nose. And just as a very brief aside, because I'd be remiss
if I didn't say this, if you emphasize nasal breathing most of the time, except
when speaking or eating. And if you downplay mouth breathing, meaning you refrain from mouth breathing, especially in sleep, you
improve the nasal microbiome. It gets better at fighting off infections. This was shown in a beautiful paper, published in Cell Reports last year. And that paper I should mention
was performed in humans. So you've got a microbiome in your nose and my nasal breathing most
of the time, not all the time. Cause there going to be times when you need to breathe
through your mouth for whatever reason, hard exercise or eating or speaking, but by
breathing through your nose, most of the time you are
creating an additional layer of immune defense against particles
that could get you sick. Whereas when you mouth breathe, you are taking down a layer of defense and you are putting yourself
more at risk of infection. This is what this paper shows. You also have a gut microbiome that is in your throat, in your
stomach and in your intestines. And that gut microbiome
is extremely powerful in regulating your mood
and your immune function. Now, this is not something
that you can sense directly. You don't know when you have a
bunch of good microbiota or a bunch of bad microbiota because
you can feel them moving around in there, actually
that would be pretty awful, that would be pretty creepy feeling. Rather that according to whether
or not your gut is alkaline or acidic in the appropriate ways, you will populate your gut with
the appropriate microbiota. So you want your stomach
to be pretty acidic, but other elements of your digestive tract are going to be more pH. And basically there's a gradient, meaning there's a low to high
pH gradient along the gut. You don't have to know what the pH should be at any one given point, because you're not going
to go and put microbiota at one location and not another. What you essentially want to
do is create an environment where the proper can thrive,
because when you do that, you greatly decrease what are
called inflammatory cytokines. So these are things that
are secreted both by cells, within the body and cells
within the brain to impact brain health and brain function
and bodily health. They go by particular name,
so there's something called TNF alpha, Tumor Necrosis Factor Alpha. It is inflammatory. It's not a good thing to
have at elevated levels. You have something called
Interleukin Six, IL-6 also causes inflammation, causes damage to tissues,
not a good thing to have elevated for long periods of time. And then you have
anti-inflammatory cytokines, things like Interleukin 10,
which reduce inflammation. And there are hundreds of these, if not thousands of these
different cytokines, some of which promote inflammation, some of which reduce inflammation. The simple way to adjust these
things in the proper ratios is to adjust your gut microbiome. The best way to adjust your microbiome is to ingest certain types of foods. So there is a beautiful literature on this now, but the most
important literature is the one that I referred to at the
beginning of this episode, which is what to ingest
and what not to ingest in terms of foods in order
to create the best conditions in your gut so that you can
create the best conditions in your brain and body. There was a study done by my colleague, Justin Sonnenberg at
Stanford School of Medicine. Justin's actually my upstairs neighbor in the building at Stanford where I work and they explored how different foods or different diets, I should say, impact the gut microbiome
and inflammatory markers. And this is a beautiful
study because it was done in hundreds of human patients. These actually weren't
patients that were sick, I should say human subjects
that were otherwise healthy from a huge variety of
backgrounds, so you had men, you had women, you had people of different races, different ethnicities. You had a huge range of backgrounds and they tracked all of that. And what they did is they
explored two types of diets. One is a high fiber diet. So dietary fibers are
non-digestible are only partially digestible carbohydrates typically. And they compared that to diets that were unchanged, except
for the inclusion of a few, to a few more servings of
fermented foods, each day, things like sauerkraut,
things like kimchi, they even explored, it
sounds pretty disgusting to me, but who knows, I've never tried it, which is fermented cottage cheese. And what they found was
that after initial period of a few weeks, where they
had people either eat a lot of fiber or eat one or two
servings of fermented foods, they had those people ramp
up their ingestion of either fiber or fermented foods, so
they kind of ease them into it. As they went baseline then ramp up to the point where they
were ingesting, you know, four or five servings of fiber or of fermented foods per day,
which sounds like a lot. But for fermented foods,
that would be, you know, four or five tablespoons
of sauerkraut or kimchi. It's not quite, it's not like huge platefuls
of fermented foods. And then they looked
at a number of things. They looked at the proteome, which is a kind of like
looking at the genome, but a bunch of proteins
that are made in the body. And they did this by fecal
samples, by stool samples, and they did this by blood
draw, which is great, it's a real power of this study. In fact, the most comprehensive
study that I'm aware of. By looking at these different
tissues across long periods of time, so many weeks, and
then returning people to their, to the diet that they were
on before they went into the study, they will were able
to establish in a causal way, how ingesting fibers or fibrous
foods versus ingesting these fermented foods on a daily
basis could impact the gut microbiome and many inflammatory markers and many markers of immune function and auto immune function. And the takeaway message
from this study is that the fermented foods far out
performed the high fiber diet. In fact, the high fiber diet
in some people was beneficial and in other people caused
issues with inflammation. This is very different than
what I was taught growing up and what many of us were taught. Interestingly they also
observed that people that ate the high fiber diet had increases in certain enzymes that lend themselves to better
digestion of carbohydrates. And I think there's an important
insight to come from this. Nowadays we kind of live
in the age of extremes where people seem to
either want to be carnivore or like never ingest a vegetable, I hear they don't even like allow pepper, but they're not even allowed, you know, sauerkraut or something like very extreme or pure plant based, pure vegan or pure. So essentially pure carbohydrate or pure animal protein, very extreme. I'm an omnivore, I like to eat a mixture of different things at
different times of days, but very extreme, but this is
interesting because what this, what these data show is that
perhaps ingesting a high carbohydrate high fiber diet,
which is really what these, the high-fiber condition really was actually makes people better
at digesting carbohydrates. This may explain why people who are used to
a, kind of a more paleo type or carnivore type diet
might eat carbohydrates and say, oh, that doesn't work
for me, I don't feel good. It might also explain why
people who predominantly eat plant-based foods and carbohydrate foods will try eating meat as an experiment, or because they lost a
bet or whatever it is and they'll do or desperation,
or they'll do that. And then they'll say, oh, I
don't feel good when I eat meat. How good you feel, it seems how well you
can utilize that food, and how much of that food
you crave may be determined in fact, it appears is determined by your food eating history,
the types of food you eat. And I think this might
explain some of the divide and hopefully might bridge
some of the chasm between these different groups that are
saying it should be one way, or it should be another. But at the core of the study
was the bigger message. The bigger message is that
all of us should be ingesting on a regular basis, daily basis, two to four servings of fermented
foods of different kinds. And why I say that is because the inflammatory markers went down, the markers of auto-immune
disruption went down, and the chemistry of the
gut therefore was adjusted in the appropriate ways. Now it's not to say that high fiber is bad or that fiber is bad, I don't want people to confuse this, but even
though this is a discussion about interoception,
about sensing the self. This is a subconscious
mechanism by which the gut communicates to many
organs, including the brain. And it's been shown in other
studies also in quality peer review journals that when
the correct gut microbiota are present and these
inflammatory markers are reduced, cognition improves so ability to focus, ability to sleep ability
to ward off infection and wound healing all enhanced, in fact, even in autism spectrum disorder, in people that struggle with
various mental conditions or disorders of the mind
improving the gut microbiome seems to have powerful effects on
improving brain symptoms. Along the lines of auto-immunity, there are a number of conditions that we call auto-immune conditions, and we will do entire episodes
about these going forward. But for people with so-called
irritable bowel syndrome, for people with Crohn's disease, for people with leaky gut, Hashimoto's, which is a kind of an
immune system self-attack on one's thyroid gland
and things like eczema, skin conditions, adjusting the
gut microbiome has been shown to be useful in positively
adjusting the symptoms of all of those, will it fix
those conditions entirely? Probably not. But can it have a significant
positive impact on them? Probably, yes. There is one thing that's worth mentioning in that list, which is leaky
gut, what is leaky gut. Here, we're talking about the guts, what is it to have a leaky
gut, it sounds awful. It sounds like something sort
of like leaking out the end of the tube, and it maybe
that too, I don't know. But leaky gut is actually
because, your gut is not a tube that's continuous, one
cell it's actually made up of many cells and those
cells form a barrier and they form what are
called tight junctions. If you have two cells and you
want to create a fence out of those cells, you bind them together. The way that the body does
this is to bind them together with what are called tight
junctions, these are, they go by names like
claudins and things like that, if you want to look them up. These tight junctions form a nice barrier, like a cyclone fence, that
things can't get past, but like a cyclone fence only
molecules of a certain size can go through those holes. So you're not going to pass a soccer ball through an intact cyclone
fence, but you could pass for instance, a feather
through that fence. So leaky gut is when the
conditions in the gut are too alkaline or the gut
microbiota are off in the gut, meaning microbiota that like
alkaline guts are living there. And those tight junctions can't
function at that particular pH and you create little
holes in that fence. And then what happens is
when you ingest foods, some of those foods
literally leak out of the gut and into the extracellular
space and into the bloodstream. And because foods include proteins and antibodies react to proteins, what ends up happening in leaky gut, and the reason we talk about
in auto-immune conditions is that you start developing antibodies to particular food proteins. And then people start feeling
like they have food allergies and they do, they actually
create particular food allergies. Now, one way to prevent
leaky gut is to get the rest of the gut situation happy
by ingesting the proper foods that we talked about before, ingesting fermented
foods on a regular basis. The other is our old
friend glutamine, again. There are some data and I
should say it's a limited number of studies showing that
ingesting glutamine anywhere from one to three, excuse
me, teaspoons per day, can help alleviate leaky gut. Now, the mechanism for that
still isn't clear whether or not it's adjusting pH or
whether or not it's creating more favorable environment
for the microbiota, but it is clear that
supplementing with glutamine can, in some people enhance where I
should say improve conditions of leaky gut, so that
might be useful as well. And then the final thing about this, I want to talk about is we're
talking about chemical sensing in the gut and how that
impacts wellbeing is about gut acidity, and this I confess
is a little bit controversial. Some people are on board,
this other people are not. And so I'd love your feedback
on this, if you, if you agree, please tell me if you
disagree, please tell me, but please tell me why you
disagree in particular, experience or data,
although it's always better if you can point me towards
peer reviewed studies. There is a practice that
some people embrace. I'm not recommending
people necessarily do this. And you would definitely
want to talk to your doctor, but where people have food
allergies or they're having mood or auto-immune issues,
and they treat this, some people recommend treating this through the ingestion of HCL,
hydrochloric acid tablets. Now hydrochloric acid can burn you, right? Acids can burn you, they
literally can melt away skin. You want to be very careful
with acids of all kinds, truly, but hydrochloric acid is sold as in supplement form
in capsule or pill form. And there is a practice
of starting to ingest one or two hydrochloric acid
tablets midway through a meal and then what people will
generally do is examine to see whether or not that improves
their symptoms of indigestion, how it relates to mood, how
it relates to well-being, how it relates to their
sensation of their gut viscera. By changing the acidity,
you also changed the way that the gut communicates with the brain through the mechanisms
we talked about before. And there are a growing number
of people embracing these practices of taking HCL. It's often combined with other
things, it's usually combined with an enzyme and that enzyme is pepsin. So most of these
supplements come in the form betaine HCL pepsin and while
they're not a cure-all, and certainly don't want to
suggest that they're a cure-all, many people that have a hard
time adjusting the pH of their gut and have a hard time
adjusting the microbiota of their gut in the appropriate
ways have benefited from taking these betaine HCL pepsin tablets
or capsules during meals. And the general instruction is to start slow, to start with one or two, and then to find a level
that you're comfortable with that doesn't create an
excessive feeling of warmth in the stomach, it doesn't
throw off your digestion. So it takes a little bit
of experimentation, again, definitely talk to your
healthcare provider before exploring this, but this has become a very
common practice for people with auto-immune disorders and
accessing the gut because it is accessible by taking things
has also become way in which people with various mental
conditions are trying to adjust their mood and adjust their wellbeing. Along these lines, I do want to mention that
there are studies that show that people that supplement
with a lot of probiotics or even prebiotics can
sometimes experience brain fog. This isn't discussed a lot and the data are a little
all over the place, but it is that we're thinking about. The goal here is not to
create as many microbiota as possible, what you want
is microbiota diversity. And I should mention this again in reference to the Sonnenberg study, which was what the high fiber diet does is it increases certain microbiota, but it limits their diversity and what the fermented food diet does, or I should say the diet that
includes regular ingestion of fermented foods a few servings a day is it increases microbiota diversity. Now, lack of microbiota diversity has a name in the medical profession. It's called dysbiosis
and dysbiosis is bad. Dysbiosis is what you see
when people are spending long periods of time on bedrest or when they've been chronically
ill, and so here again, we're talking about creating
a positive environment in the gut, either by adjusting acidity, maybe you explore the
betaine HCL pepsin thing. I think if you have healthy digestion, if you feel like you
have a good relationship to your gut, and it has a
good relationship to you, sort of a silly phrase, because
it is you and you are it, then I don't think there's
any need to pursue this, but if you don't, that might
be one avenue to pursue. However I think primary in all of this is the fermented food findings, and it's not just one study,
it's many many findings that now bring us to a place where a huge center of massive data are
pointing us in the direction of saying ingest fermented
foods on a regular basis. I should also mention that
conditions like sarcopenia, which is the loss of
muscle tissue as we age, has been shown to be offset by
improving the gut microbiota. So while today is about interoception, we're
talking about sensing, we're also talking about
subconscious sensing. What are we talking about,
subconscious sensing, we're talking about subconscious sensing of the milieu of the body. When the milieu of the
gut and the body is right, than the brain and the immune
system function very well. And so this isn't something
where you can sit back and say, oh, you know, I feel
all those good microbiota in my gut, or, oh, no,
those are bad microbiota. You can't do that unless you're
going to take fecal samples and blood samples and analyze them in the, with the extreme exhaustive nature that the Sonnenberg and other labs do, you're not going to get
that kind of information. I know there are companies out there that do this, and I don't
want to knock on any of them, but I do want to
emphasize that to do this right, to really analyze which
cytokines you're making, which ones you're not, you really need to look
at a huge number of them. And that requires large-scale proteomic and genomic and inflammatory
markers screens. It's just not the kind of
thing that most commercial enterprises can really provide to people in a way that
they can interpret, rather, this is a case where you can
simply go to the effector, to the thing that can
actually move the needle in the right direction for you. It's very clear that's fermented
foods and that's keeping the stomach slightly more acid than one might think you would want to. So let's talk about barfing first. Barfing, AKA vomiting, is when
the contents of your guts run in reverse, meaning when
they go up from your stomach. Sometimes even up from the intestines, even though that sounds horrible, it sometimes happens up,
out the esophagus and mouth and onto whatever surface
happens to be in front of you. It's a terrible thing,
nobody likes to do it, but it's a very interesting
aspect of our biology because it reveals a beautiful and absolutely
fundamental relationship between our chemistry and our brain. So your brain is actually
locked behind a gate and that gate is not your skull. That gate is the so-called
blood-brain barrier. So just like your gut has these
epithelial tight junctions, the things I talked about
before that provide a fence, so things can't get through
and get through in leaky gut, your brain has tight
junctions that are very tight. It's absolutely fundamental
that only certain molecules get across the blood brain
barrier and that others don't. And the reason for that is
that most all 99.99999% of your neurons do not regenerate, I
don't care what you've read, especially in the news recently
about how psychedelics cause neurogenesis, because they
don't, it's absolutely wrong. Psychedelics have effects on brain plasticity, but they have nothing to do with neurogenesis, at least no data to support it, but because
you can't make new neurons, you also can't damage the ones you've got, or you shouldn't as much as possible. And that's why you have a
blood brain barrier or a BBB. So the BBB as it's called
prevents substances from getting to the brain,
however, like any fence, it is not always uniform along its length. And there are little spots
within that fence where chemicals can sneak across to the
brain and through a beautiful design, I don't know
anything about the design. As I always say, I wasn't
consulted the design phase. I'm not talking about any
kind of intelligent design or anything that is not
the topic of this podcast. This is not a philosophy podcast, nor is it a religion podcast,
it's a science podcast, but through a beautiful design of some sort, there are
little holes in that fence. And they're little neurons that
sit right behind those holes and those neurons sense what
the chemistry of the blood is. So I'm guessing you probably
didn't imagine that today's discussion about sensing the self would be sensing your
own blood, but you do. There's a little area of your
brain, that's little indeed, but is very important called area postrema P-O-S-T-R-E-M-A. And area postrema is an
area of the brainstem that sits right next to another brain area called the chemo receptor trigger zone. And when the contents in your bloodstream are of a particular kind, meaning when there are
pathogens or it's too acidic, the neurons and area postrema the neurons in the chemo receptor trigger
zone, the CTZ as it's called, trigger a bunch of motor
reflexes in the abdominal wall that make you barf. Okay, the feeling that you
need to throw up is triggered by these neurons in the brain stem. And those neurons in the
brainstem are triggered by the presence of certain chemicals. And the reason why you don't
have any blood brain barrier at that location is because
post-trauma has to be there like a crossing guard, making sure that everything
that's coming through the blood is okay, and if it even
senses just the tiniest bit, that things are off, it's
going to trigger that reflex. Now, the really interesting thing is that the neurons and area
postrema respond to the chemistry of the blood, but they also will respond to our consciousness,
to things that we think and things that we believe
and even particular memories. This is why when certain people see vomit or see someone else vomit, or
even somebody else heaving, as if they're going to vomit, they themselves feel as
if they're going to vomit. I'm guessing they're probably
even a few of you right now that feel like you might vomit. You might feel salivation in your throat, which is always a precursor to vomiting. Some people, the memory of, or the thought of something
like blood or vomit or, use your imagination, can
actually trigger the vomit reflex. And that's because these neurons
in area are very sensitive to prior experience of
interactions with negative things. So and actually, as I'm saying this, I feel my gut kind of
cramping up again, I'm not, I don't vomit very easily, I'm not one of those, nor am I somebody
who's never vomited. And here we are talking
about my vomit history, but I think it's appropriate in this, in this context,
the neurons of area, or they're basically to keep
your whole system safe and thank goodness they are, because
for instance, some people, unfortunately, they drink so much alcohol that they throw up. Have you ever wondered why that is? Well it's because alcohol
fundamentally is a poison. I'm not saying for, you know, age appropriate folks that
ingesting alcohol is bad. This isn't a judgment call, but alcohol itself at excessive levels in the bloodstream triggers
post-trauma to cause vomiting. So this is an example,
whereby memories, context, but also just the chemistry
of our internal state is triggering behaviors
that are very hardwired. They're very reflux driven. And why would it be that
some people get more nauseous than others at a given level, well, they'll have to do with alcohol tolerance. Some people have what's
called a, you know, we refer to as a stronger
stomach or a stomach of steel. Other people they throw out very easily if they don't feel well,
or if they ingest anything that's just a little bit off. From a purely adaptive standpoint, it's probably better to vomit up things that aren't good for you rather than to have them
pass through your system. Especially if those things
are contained in lipids. For instance if you ingest something that's in liquid form because cells, literally every cell in
your body is surrounded by a little thin layer
of fatty tissue, we call the bilayer membrane,
it's a little membrane. Fat can move through fat very easily. And so any bad stuff you ingest can get stuck in your system. So let's talk for a second about how to reduce nausea, because
nausea is that salivation, that feeling that you're
going to vomit, can be very beneficial in an, in an
adaptive circumstance. Like you've ingested something bad, but some people experience
nausea, for other reasons, there are good ways to regulate nausea and the ways they regulate
nausea, very interesting. They actually adjust the activity of these neurons in area postrema or they change the chemistry
of the blood directly. And many of you have heard
this before, perhaps, but it turns out that there are good data, 11 research studies where the
ones that I could find peer reviewed research studies with no bias, so independent studies showing that ginger can cause a notable reduction in nausea, how much ginger, one to three grams, what's one to three grams where
you have to measure it out on a scale, unless you're taking
it in pill or capsule form. It doesn't seem to matter if you take it in pill or capsule form, so
this thing that you've heard before that ginger can reduce
nausea, indeed is true. Peppermint, apparently can also do that. And some of you will not be
surprised to learn that cannabis can reduce nausea, not
surprise because cannabis, which has different legality
in different places, and I understand that, so please take that into consideration. But cannabis, THC and, or it turns out CBD can reduce nausea, that's been shown in at least one study. And it probably does that,
not by changing the chemistry of your blood, but by
changing the threshold for firing of these neurons
in area post-trauma. And there are conditions
such as in chemotherapy and radiation therapy and others
where people are feeling very nauseous, I'm not recommending
people go use cannabis, unless they've decided with their selves and their family and their
doctor that they should. But what's interesting
is this thing about CBD and we'll do a whole episode
on THC and CBD doesn't have, or isn't supposed to have
these psychoactive properties that THC does. Although CBD can have a
mild to major anxiolytic anxiety-reducing effect, but it does appear that the
data are what the data support. I should say, the anecdotal reports, which are that cannabis can reduce nausea. So to barf less, ginger, peppermint, and if appropriate and legal
for you, possibly cannabis. Now let's talk about fever. In previous episodes,
and in future episodes, we deal with thermal regulation, which is the body's ability
to regulate its temperature. Talk about cold and heat and saunas and ice baths
and physical performance. We're not going to deal
with all that right now, but I promise we will going forward. Today, I only want to talk about fever because fever directly
relates to interoception. What do I mean by that? Well, a fever is simply an
increase in body temperature, that increase in body
temperature is triggered by neurons in the brain. And those neurons in
the brain are triggered by the presence of particular
things in the bloodstream. What sorts of things? Well, toxins, bacteria, viruses, when something bad gets in our system, the body doesn't know it's bad,
it just knows it's foreign, and it hasn't seen it before. Or that it's in the wrong
compartment of the body. So earlier we were talking about proteins that leak out of the gut
and get elsewhere, you know, you don't want a piece of
steak sitting in your bicep. That would be bad, you would
actually develop antibodies, you would have a horrible infection. But your body has this intelligence, and that intelligence is to know, Hmm, these proteins are normally
not seen in this region and then your body or the
cells there, I should say, we'll release something that
then will travel to the brain and will trigger an increase
in body temperature so that your body cooks the bad thing
or the cause of the bad thing. It's really a beautiful
adaptive mechanism. We always think fever is so terrible, but fever is there to cook the
bad thing that's inside you, or that has left the correct
compartment inside you and is in the wrong
compartment inside you. So what's beautiful about
the fever mechanism is that it looks a lot like
the barfing mechanism. Basically you have a set of
neurons that sit near the ventricles, remember the
ventrals is hole in the tube, that is you, the tube
that is, you are a tube, a series of tubes. And your brain has a hole down the middle. And it extends down to the
bottom of your spinal cord, at the front, it's called the ventricles, they start with what are
called the lateral ventricles and the excuse me, starts with the third and
the lateral ventricles, and then it goes to the fourth ventricle and then to what's
called the central canal. But basically is just a
big space in the middle of your nervous system in
the middle of your brain. And you have one ventricle that I already mentioned
called the third ventricle. And it's shaped kind of
like a thin oval up upright, if you're listening to
this, just think an I, the shape of an I, but it's
kind of rotated 90 degrees. So it's up and down as opposed to across. And along that third ventricle, there's there a little
neurons that can sense what's in the cerebral spinal fluid
that fills the ventricle. So in other words, you have neurons that
are sensing the chemistry of your cerebral spinal fluid, and that have access therefore to the chemistry of your body. Because that cerebral
spinal fluid is going up and down the brain and spinal cord. But into that cerebral
spinal fluid are signals about the various
chemicals within the body. So this is not a mechanical system. This is a chemical system. Remember we're talking
about mechanical information and chemical information
accessing the brain. So if you have something bad in your system, you've ingested a, you breathe in a virus or
you inhaled some bacteria, or you got a cut on your leg and some bacteria are growing there. Of course, locally, there will be effects, little things called the mast cell. This M-A-S-T little packets
of histamine literally will go there and explode
[poofs] and cause inflammation, which is actually a good inflammation. And we'll release little things called macrophages to
gobble up the infection. The other day, it was
in Texas, it was some mean little mosquitoes in
Texas, and a lot of them, and I would stand outside
and I'd get bitten, I didn't feel a thing,
but then later that night, they started swelling up and itching and then I'd itch them, and
then they'd swell even more. That was because of the release of mass cells, of histamines
inside those mass cells that would literally causing
inflammation of the tissue. It wasn't the poison
from the mosquito itself. It was the immune response to those. Well, you also have this systemic or body-wide attempt to kill
stuff, and that's the fever. So the neurons that these
ventricles with cerebral spinal fluid go by a particular
name, they're called circumventricular organs,
meaning near circum, ventricular near the ventricles. And you have these organs
and there are a set of neurons, has a really
cool name called the OVLT. I don't know why I like
that, but I just like it, it's the organum vasculosum
of the lateral terminalis organum vasculosum of the
lateral terminalis, OVLT are the neurons that respond to toxins and bad stuff in your bloodstream,
however minor or major. And they release things like ILK-1, which are inflammatory cytokines
inflammatory in this case is good, you want inflammation
at the site of an infection. It's a good thing. It's going to help with healing. And it's going to change
the conditions in your body, what's going to happen is when those OVLT neurons are activated, because you have
something bad in your body or something bad is
happening in your body, they communicate with an
area of the brain called the preoptic area of your
hypothalamus and the preoptic area cranks up your temperature and
tries to cook that bad thing. Now it's worth talking about fever for a moment and talking
about thermal regulation, because I think this actually
could save some lives. So if you are overheated
to a point where, you know, you're getting up past 102 or 103, it's going to vary depending on person to person and
certainly age, you know, kids, some people think can
tolerate higher levels of fever than adults, but look, you always want to be cautious
about heating up the brain too much, because once
those neurons are gone, they do not come back and
neurons do not do well in very high temperatures. Once your body temperature
starts getting up to 102, 103, certainly 104, you are starting to enter
serious danger zone. This can happen through
exercise in hot environments or an inability to escape heat because you don't have covering or adequate ventilation or cooling. It can also be because of excessive fever, for whatever reason. A lot of people think the way
to deal with this is to put a cool compress on the back of
the neck or to cool the torso. In discussing this with
my colleague, Craig Heller who's at Stanford School of Medicine, and he's on the undergraduate side of the campus as well, runs a biology lab. He's a world expert in thermal regulation. It's very clear that
that's the wrong response to try and cool off the body. If you put a cold towel
or you put an ice pack on the back of the neck, what
you effectively do is cool the blood that's going to the brain. And if you do that, then your brain will react
by turning up the crank in so to speak on the neurons
in the pre optic area, and will heat you up further
and can cook your brain and organs further. So what you want to do is, as I've talked about before, you want to
cool the bottoms of the feet, the palms of the hands and
the upper part of the face. And I'm not going to
go into all the details as to why you want to do that right now, but those are the
locations you want to cool. Now you can also cool
the rest of the body, but it's not okay to just
stay under the covers and just cool, you know, the
neck or something like that. You really want to try
and create a systemic or whole body cooling, if the
goal is to bring fever down, but in many cases, fever is adaptive. And so taking a non-steroid
anti-inflammatory drugs like Advil and Tylenol sometimes can be good,
if that's recommended, but other times, because
it reduces your fever, it's allowing that pathogen, that pyrogen, it's sometimes called, a pyrogen is a substance
that causes fever, think pyro, think fire, think
pyromaniacs, think pyro, those pyrogens can survive at
moderate to low temperatures, and they can't survive
at high temperatures. So the fever is an adaptive
mechanism and the OVLT, and the sensing of your
chemistry is how the OVLT, organum vasculosum of the
lateral terminalis does that. So we've talked about sensing lung volume, speed of our heartbeat, we talked about sensing the gut volume, the intestinal volume,
or the absence of volume. We talked about chemistry of
the gut and the gut microbiota and auto immune functions. And we've now talked about
vomiting, and we've talked about fever, lots of aspects
of sensing our internal self. Now I want to turn our attention to interoception as it
relates to feelings, the way that interoception
is most commonly described. And I want to highlight a term that many of you have probably heard,
which is the vagus nerve. We talked about vagus
a little bit earlier, but the vagus nerve, this
vagabonding wandering nerve is involved in everything I've
talked about up until now. And the reason I saved it till now, rather than mentioning all
along is to highlight a specific point, which is that whenever
we hear about the vagus in popular culture, it's like
the vagus calms you down, you want to stimulate the vagus by rubbing in front of the ear, and
it's a parasympathetic nerve, and it will calm you down,
he'll mellow you out. Actually, most of the time,
the vagus is stimulatory. When you ingest foods
with amino acids, sugars, or fatty acids, the vagus nerve gets activated and triggers the release of dopamine, it makes you more alert and go seek more of those foods or what
led to those conditions. When you feel nauseous
it's rarely calming, when you feel like you have
a fever, it's rarely calming. So you're starting to
get the picture that even though the vagus nerve is in
the parasympathetic branch of the autonomic nervous system. And if that doesn't mean anything to you, because you're not in
aficionado, don't worry about it. But it's not a calming system,
it's a communication system, and it's a motor system. It communicates brain to
body and body to brain, and it changes the function
of different organs, now, one thing that's important
to highlight is that stress itself will alter the
chemistry of your gut because of the ways that
it down the vagus nerve and quiets the neurons that
communicate from gut to brain. I want to say that again, stress will disrupt your gut and make you feel not
good, poor digestion, and just lousy, because
of the way that it shuts down the vagus nerve and
the neurons of your gut. So what stress does is it
blocks the communication between gut and brain, it
doesn't mess up your gut. It just doesn't let your
gut get the signals up to your brain, and it also
then throws off the chemistry. And then there's a whole
cascade of effects. If you want to learn more about stress, I did a whole episode
called "Master Stress," or I think maybe it was
called "Conquer Stress" and it was "Master Stress," either one. The whole point of that
episode is to give you tools and practices to deal with
short term, acute stress, moderate term stress, and
long-term chronic stress through behavioral mechanisms, nutrition, supplementation,
and many other things as well. It's chockablock full of
protocols and tools for stress. The vagus nerve, however, is responsible for emotion
and the way it does that is to pool, to aggregate the conditions of your gut, the conditions of your heart and the conditions of your breathing, which includes your diaphragm
and lungs and takes that kind of as a collection of
information and sends it to the brain and controls
what we call your emotions. Now that might seem
obvious to some people, but to other people that
might seem totally crazy. You thought your emotions were
because the market was down and you had invested, or because something that
you thought was going to happen is not going to happen, or because you thought
that school was open and then it's not, or
maybe thought it wasn't, and it is whatever it is that bothers you, you think of generally as
a purely cognitive event. But the brain doesn't really know what to do with that information. It doesn't act directly on that
information to create moods. Moods are created through
the heart's response to reading that headline, to
the change in your breathing, that's caused by someone
that you love telling you that actually they're not interested in spending time with you anymore, or that you screwed up or
that they're interested in spending a lot of time with
you and you like that, right? Emotions can be good or bad or neutral. So this thing that we call interoception, the sense of self I've been building up from very fundamental
layers, gut chemistry, spleens, immune systems,
auto-immune and you might've been thinking, wait, I thought this was going to be about a sense of self,
a noticing or a feeling. And indeed all of those things
are plugging in like a series of ingredients in a recipe that gives rise to your mood and how you feel, and that mood and how you feel is shown in one location in your body
that other people can see. And that's in your facial expressions. And indeed there are now
beautiful data showing that your face, including
the size of your pupils, the tonality of your
face, how flushed you are, or how pale you are, even the degree to which you're frowning or smiling relative to
other periods of time, that is all an aggregate
of, or a reflection rather of your gut, your heart and your breathing and the chemistry of your body. And so this is why I sort of
backed into this conversation about interoception I kind
of Trojan horse this on you on purpose which is that when we talk about the
vagus and you hear, oh, you know, you can get vagal
tone by breathing or rubbing on the front of the or
short that's probably true, but another fundamental layer
is the acidity of your gut, how fast your breathing
are you inhale-emphasized, or exhale-emphasized breathing. When we are relaxed our
pupils tend to constrict. When we are very alert, our pupils tend to be
dilated, whether or not that alertness has to do with
being happy or being sad. And what's remarkable, and
this is where interoception really takes a leap into the incredible is that there are
beautiful studies that show that for instance, when we
know somebody pretty well and they are going through
some sort of experience of any kind, our heart rate actually starts to mimic their heart rate. Our breathing starts to
mimic their breathing, even if we aren't conscious
of their breathing. It's not like we see their chest heaving, and we think, oh my goodness,
and then we breathe that way. There's a mirroring and no it's not carried
out through mirror neurons. Mirror neurons are more
of a myth and a reality, sorry to burst people's bubbles. But that bubble around mirror
neurons is definitely made of myths and a topic for another
time, but we start to mirror. Somehow human beings are able
to register the internal state of other beings, and I think
probably for animals too, but certainly for other
humans, even at a distance. And these studies are many now, and they're really wonderful studies. And so your sense of
your internal landscape is linked to others. Now you can enhance this
interoceptive capacity for how you feel and how
others feel, in other words, you can start getting a better
readout of your internal state by doing a simple
exercise, what is really a tool. And that is to learn to
sense your heartbeats. So some people are very good
at this, other people are not, some people can do this more
easily when they have all their air exhaled and some
people can do it better when they are holding a breath hold. But one thing that's kind of cool about this whole interoceptive capacity is that you can enhance it very quickly. You can learn or teach yourself
to have heightened levels of interoception in a way that
you can't really just give yourself heightened levels of vision by snapping your fingers, in
one of one tool or exercise, there are things you can
do to improve vision. That's the topic of a previous episode. I encourage you to look it up. There are things you can
do to improve your hearing and your taste and your smell,
we talked about all those, but with interoception you can get very good at this very fast. And I think this is one of the reasons why meditation is powerful. Think there are a lot of reasons
why meditation is powerful, but one of the reasons
is when you stop taking in exteroceptive information
from the outside world, by closing your eyes and
focusing inward, as they say, you start paying attention
to your breathing cadence, you start directing your mind's attention to your heart rate, and if you can start to
perceive your heart beating. You actually are very quickly strengthen the vagal connections between
the body and the brain. And so there's no real practice here. There's no breathe this
way or do this thing except to direct your awareness
toward your heartbeat. And some people can get
very good at this very fast. Most people find that just by doing this for a minute or so, every once in a while, they start to tap into this sixth sense. They start to notice when
they don't feel quite right about something or
somebody or some situation, or they start to notice
when they feel quite right about somebody or something
or some situation. So this interoceptive
awareness can be tuned up. It used to be called vagal tone, but I think that term doesn't
take into account all the other things that are
going on with the vagus. So I don't really like that term. It's more of an interoceptive awareness. And again, there are
many studies now showing that for sake of bettering
one's mood overall, for sake of moving through
a challenging phase in life, for sake of just
enhancing one's experience of life overall, whether or
not it's the taste of foods, interactions with other people,
enjoyment, focus, pleasure, tuning up one's interoceptive awareness is both easy again by just
taking a minute or two and trying to count heartbeats. And then this works best, of course, if you have some independent
readout of heartbeats and you can compare, you can see
how accurate you are, but even if you don't use
a device or have a device to do that, without taking your pulse, using your thumb on your wrist
or something, or your fingers on your neck, as you typically
would for taking your pulse, trying to sit still for a
minute or two every once in a while, maybe once a
week, maybe twice a week, maybe while you're meditating,
maybe while breathwork, maybe during the breath
holds of breathwork, you don't really have to do this in any kind of extended way, you can very quickly increase
your interoceptive tone. And that has a huge and outsized effect on the brain, body relationship and your brain's ability to tap into both the subconscious
and the conscious aspects of this chemical and mechanical signaling that's happening all the time. And it can have real and
out-sized positive effects on your ability to engage with other people and your
ability to focus at work and your ability to notice, ah, I'm finding myself kind of
feeling like I'm losing focus, but really it was my heart
rate was just increasing. Maybe I just exhale a little bit and bring my heart rate down. So whatever effectually tried to do today is to give you a window into
this incredible relationship between your viscera and
your brain and your brain and your viscera, all
these organs of your body, and what I hope is that you'll appreciate that it's a system, that you
aren't just a system of tubes. I said that in a sort of in jest, I mean, you have a lot of tubes and
you are a system of tubes, but that system of tubes is
linked through the nervous system, and those links
work in very specific ways. So whether or not you remember
about pesos and all the GLPRs and all that stuff, it
doesn't really matter. What I encourage you to do
is start sort of pushing and pulling on the various leavers
within this beautiful system that we call the interoceptive
system, this sense of self. If you're learning from this
podcast and or if you're enjoying it, please subscribe
to our YouTube channel. That really helps us. Also on the YouTube channel, please leave us comments and feedback, including feedback of topics
you'd like to see in future episodes or guests, you'd like
to see on future episodes. We do read all the comments. In addition, please subscribe
on Apple and Spotify and follow us on Instagram @hubermanlab. If you want to leave us a
five-star review on Apple, you also have the opportunity to leave us a five-star review. You can also leave us comments and feedback on Apple. During the course of today's episode, and on previous episodes,
I mentioned supplements. I realized supplements
aren't for everybody, but for those of you that are
interested in supplements, it is important that the
supplements that you take have a high level of stringency
with respect to the amounts of the contents that are
listed on the bottle matching what's actually in the bottle,
in the capsules and tablets, and that the quality of those
ingredients be extremely high. For that reason we partnered
with Thorne, that's T-H-O-R-N-E because Thorne supplements
have the highest levels of stringency for both
the content and the amount of content in those
bottles and supplements. If you want to try Thorne supplements, and you want to see the
supplements that I take, you can go to thorne.com/U/Huberman. And you can see all the
supplements that I take. You can get 20% off any of those. And if you enter the Thorne
site through that portal, you can get 20% off any of the supplements that Thorne makes. In addition we have a Patreon account, it's patreon.com/andrewhuberman. There you can support the podcast at any level that you like. Please also visit us at hubermanlab.com and sign up for our free
newsletter, our newsletter starts in August 2021, and you'll
be receiving protocols and excerpts from podcasts, some condensed information
that we think will really be a value to you,
it's totally zero cost. Again, just go to
hubermanlab.com and sign up for what we call our
Neural Network Newsletter. And most of all, thank you
for your time and attention. And thank you for your
interest in science. [upbeat music]
