- Welcome to The Huberman Lab Podcast, where we discuss science
and science-based tools for everyday life. [bright music] I'm Andrew Huberman and I'm a professor of
neurobiology and ophthalmology at Stanford School of Medicine. Today we're talking all about sleep and how to optimize your sleep. This is a topic we've covered
previously on this podcast in the episode called "Master Your Sleep." However, since the airing of that episode, there's been some terrific
new science to come out. I've also received thousands, yes, literally thousands of questions related to the specific
protocols covered in that episode as well as in the episode
on jet lag and shift work. And while today's episode is not specifically about
jet lag and shift work, we are going to cover tools that will allow you to shift your schedule if you need to for work or travel, and we will also cover tools that will allow you to fall back asleep if you happen to wake up
in the middle of the night or if you get a poor night's sleep, how to actually recover from that poor night's sleep more quickly, and yes, indeed, even replace
sleep that you've lost. So today's episode is going to be filled with practical tools. We will touch on some of
the underlying science, but it's really designed
to be a practical toolkit for optimizing your sleep depending on your specific sleep needs. Various times throughout today's episode, I will refer to studies that
form the backbone of the tools that I'll be describing. But whereas most of the
podcast episodes here tend to be deep scientific
mechanism and then tools, scientific mechanism, then tools, today I'm mainly going to
focus on the practical tools that anyone, indeed, all
people, I believe, should use in order to optimize their sleep. Why should everybody want
to optimize their sleep and put considerable effort
into optimizing their sleep? Well, put simply, sleep is the foundation of mental health, physical health, and performance of all kinds, cognitive performance, physical
performance, et cetera. It also controls things
like our immune system, wound healing, our skin
health and our appearance, whether or not we can
think clearly or not, whether or not we will live as long as we possibly can or not, whether or not we suffer from dramatic age-related
cognitive decline or not. In other words, whether or not
we keep our memory as we age. I could go on and on about all the terrible things
that can happen to somebody if they don't sleep well. Thanks to the great work
of Professor Matt Walker at University of California, Berkeley, and the wonderful book that
he wrote, "Why We Sleep," I think the world is largely onboard now that sleep is critical to our health, our mental health, our physical
health, and our performance, but what's not often discussed
is how great life is, that is, how much more
focused and energetic and how positive our mood gets, when we are sleeping for the
appropriate amount of time at the appropriate depth and when we are doing that regularly. Basically everything in life gets better when we're sleeping well. So today I'm going to teach you the tools that will allow you to
optimize your sleep. That is, get to sleep and stay asleep, fall back asleep if you wake
up in the middle of the night, and adjust your sleep given the various life demands
you may be experiencing. I'm pleased to announce that
The Huberman Lab Podcast is now partnered with
Momentous supplements. We partnered with Momentous
for several important reasons. First of all, they ship internationally, because we know that
many of you are located outside of the United States. That's valuable. Second of all, and perhaps most important, the quality of their
supplements is second to none, both in terms of purity and precision of the
amounts of the ingredients. Third, we've really emphasized supplements that are single-ingredient supplements and that are supplied in dosages that allow you to build a
supplementation protocol that's optimized for cost, that's optimized for effectiveness, and that you can add things and remove things from your protocol in a way that's really
systematic and scientific. This is really hard to do if you're taking blends
of different supplements or if the dosages are such
that you can't titrate, or that is, adjust the
dosages of a given supplement. So by using single-ingredient supplements, you can really build
out the supplement kit that's ideal for you
and your specific needs. If you'd like to see the supplements that we partner with Momentous on, you can go to livemomentous.com/huberman. There you'll see those supplements. And just keep in mind that
we are constantly expanding the library of supplements
available through Momentous on a regular basis. Again, that's livemomentous.com/huberman. Before we begin, 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 InsideTracker. InsideTracker is a
personalized nutrition platform that analyzes data from your blood and DNA to help you better meet your health goals. I've long been a 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 analyzed from
a quality blood test. And nowadays, with the
advent of modern DNA test, you can also get insight into, for instance, what
your biological age is and compare that to
your chronological age. And, of course, your biological age is really the age that counts. The problem with a lot of blood tests and DNA tests out there, however, is that you get information back about the levels of metabolic factors, lipids, hormones, et cetera, but you don't know what to
do with that information. InsideTracker makes that
all very easy to navigate. They have a personalized platform. So this is a web portal where you can go, you'll see the numbers from
your blood tests and DNA tests, and then it will tell you, for instance, how you could adjust various
aspects of your nutrition or your exercise or supplementation in order to bring those numbers into the ranges that are best for you. If you'd like to try InsideTracker, you can go to insidetracker.com/huberman to get 20% off any of
InsideTracker's plans. That's insidetracker.com/huberman
to get 20% off. Today's episode is also
brought to us by Eight Sleep. Eight Sleep makes smart mattress covers with cooling, heating, and
sleep tracking capabilities. It turns out that your body temperature and your ability to fall and stay asleep are very closely related. If your body does not drop
by one to three degrees, you are simply not going
to get into deep sleep or stay in deep sleep. And waking up, it also turns out, is related to body temperature. Every time you wake up in the morning, your body is warming up
in order to wake you up, and this has an enormous number
of hormonal and metabolic and other cascades that
are vitally important, not just to what happens while you sleep, but your health and your energy and focus throughout the day. Eight Sleep is an incredible device. It's one that I've been
using for six months or so, and it's completely transformed my sleep. And I already thought I
was sleeping pretty well. The way it works is that you
can cool or heat your mattress according to different
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can cool your mattress if you tend to run warm and that will help you
fall and stay deeply asleep and then toward morning, you can have the mattress programmed or, I should say, the
mattress cover programmed, so that you warm up your
sleeping environment and you wake up when you want to wake up. If you've been sleeping pretty well but waking up in the middle of the night, you might also find that by cooling your mattress even further toward the middle of your sleep about, well, you'll stay in
deep sleep much longer. If you'd like to try Eight Sleep, you can go to eightsleep.com/huberman to check out the Pod Pro Cover and save $150 at checkout. Eight Sleep currently ships within the US, Canada,
and the United Kingdom. Again, that's eightsleep.com/huberman to save $150 at checkout. Today's episode is also
brought to us by LMNT. LMNT is an electrolyte drink
that has everything you need in order to get your brain and
body to function at its best, but none of the things you don't, in particular, sugar. Electrolytes are vitally important to the way that your neurons,
your nerve cells, work and, indeed, to the way that all the cells of your body work. But your nervous system and your neurons particularly depend on electrolytes because you need the electrolytes, sodium, magnesium, and potassium, in the proper ratios, in order for those nerve cells to fire what are called action potentials, which are the electrical signals that allow your neurons to work and to allow you to do everything from remembering information to moving your muscles deliberately. When you exercise, or even if you don't, you can get quite low on electrolytes, especially on a hot day. You can get dehydrated. There are lot of different ways to replenish your fluids and electrolytes and there are a lot of different electrolyte drinks out there, but many of them contain a lot of sugar. And some of those that
don't contain a lot of sugar don't have the proper ratios of sodium, magnesium, and potassium. If you'd like to try LMNT, you can go to drinklmnt,
that's L-M-N-T, .com/huberman to claim a free LMNT Sample Pack with your first purchase. Again, that's drinklmnt.com/huberman to claim a free sample pack. Let's talk about sleep and
tools to optimize your sleep. I want you to conceptualize yourself as contained within a room that has only very few windows
or very few entry points. What do I mean by this? Well, your brain and your
nervous system control whether or not you move or don't move. They control whether or
not you're digesting food or you're not digesting food. They control whether or not
you're stressed or not stressed, happy or sad, et cetera. All of that stuff that
controls all that stuff is housed inside your
skin and skull, et cetera. That might seem pretty obvious, but what that means is that
for your brain and body to feel alert and focused, ready to move and
exercise or do some work, or if your brain body are going
to lie down and go to sleep, well, that brain and body
needs cues, it needs inputs, to determine when to do
those different things. And those cues and inputs arrive through a defined set of
what I'll call stimuli, but you can also think of
these as levers or tools. The main levers and tools
that are going to allow you to control when you are
awake and when you are asleep and to get better sleep every single night are light, literally
photons, light energy, could be from sunlight, could
be from artificial light, we will discuss those
particulars in a moment, as well as darkness. That is the absence of light. So we've got light and dark. Those are two very powerful tools to encourage your nervous system to be in one state or another, meaning awake or asleep. Temperature is another tool or lever. Turns out that when your
body is cooling down, you have a greater tendency
to fall and stay asleep. In fact, every night
when you actually sleep, your body is dropping
by one to three degrees and that drop in temperature is required. It's like a gate that your
body has to go through in order for you to get into sleep. And in fact, the converse is also true. If your body heats up by
one to three degrees or so, you will wake up. So you've got light,
dark, temperature, food. And when we say food, we mean what we eat, when we eat, and the amount that we eat. Okay, so light, dark,
temperature, food, exercise. And of course, exercise
comes in different forms. We can do cardiovascular exercise that can be low-intensity,
long-distance exercise. It can be high intensity, so-called high intensity
interval training. It could be weight
training. It could be yoga. It could be swimming, any
number of different activities. But exercise, in general, causes an increase in body temperature and tends to make us more alert, not just during the exercise, but in the immediate
hours after that exercise. Exercise does some other things that relate to our sleep as well and we'll talk about those today and how you can leverage them. Another potent lever for adjusting your sleepiness
and wakefulness is caffeine. This, of course, comes
as no surprise to people, but why and how caffeine works
might come as a surprise. Very briefly, we have a molecule in our body called adenosine and the longer we have been awake, the more adenosine builds
up in our brain and body and adenosine is part of the
reason why we get sleepy. Caffeine effectively operates
as a adenosine antagonist. It works by basically occupying
the receptor for adenosine. So it's a little bit of
a convoluted mechanism. But basically all you need to know is that caffeine prevents
the actions of adenosine. That's one of the reasons why
caffeine makes us feel alert. But how much caffeine we drink and when we drink caffeine turns
out to be vitally important for adjusting our wakefulness and for optimizing our sleep. So we'll talk about that as well. The other category of lever or tools which are immensely powerful
for optimizing sleep are supplements. There now exist as many as
eight different supplements that can powerfully modulate
sleep in healthy ways and that have huge margins for safety. So we're going to talk about
what those supplements are. In previous episodes of this podcast and as a guest on other podcasts, I've talked about three
particular supplements, magnesium threonate,
apigenin, and theanine, which together can really enhance the speed at which one falls asleep and people's ability to stay asleep and to really get into
those deep stages of sleep that are particularly restorative. Today we're going to
talk a little bit more about each of those three and how they can best
be used in combination, but we are also going to touch
on some other supplements that I have not talked about
much before, if at all. Things like glycine and
GABA, as well as inositol. Many people are going to
find inositol interesting and of particular use to them, especially if they're following
a low-carbohydrate diet or if they are fasting before sleep or just trying to avoid
eating too close to bedtime and yet they're having a
hard time falling asleep. Inositol also turns out
to be especially useful for people who have a tendency to wake up in the middle of the night and have a hard time falling back asleep. It also has some interesting
and potent effects on anxiety throughout the day. So we're going to talk about
inositol as a tool as well. And then last in our list
of general categories of levers and tools for optimizing sleep are digital tools. Now, when we say digital tools, I don't necessarily mean devices. What I mean are things like
non-sleep deep rest scripts. These are zero-cost
scripts that you listen to that take your body through
some deep relaxation and that can help people both
fall asleep, stay asleep, fall back asleep, and
get better at sleeping. And also going to talk about digital tools related to self-hypnosis. This is distinctly different
from stage hypnosis. So I know some of you hear
hypnosis and you think, oh, you know, people
clucking like chickens and doing things that are
outside their control. That's not at all what
I'm referring to here. I'm talking about clinically
and research-supported tools that have been shown to
enhance people's ability to fall and stay asleep and that can get you
far better at sleeping. So again, to recap the
list of levers and tools, we've got light and dark, and that includes the intensity of light, the timing of light, et cetera. We've got temperature. We have food. We have exercise, caffeine,
supplements, and digital tools, not just limited to devices, but zero-cost tools that
you can access on YouTube and elsewhere in various apps that can really help
you optimize your sleep. So today we're going to
talk about all of these. I really want to provide you
as many tools as possible, give you the logic behind
each of those tools and when and how best to apply them so that you can develop the sleep toolkit that's ideal for your sleep needs. As we head into our description of tools for optimizing sleep, let's consider what the
perfect 24-hour cycle would look like. Let's start this 24-hour cycle with when you wake up in the morning. So for some of you, that will be 5:00 a.m. For others of you, that will be 10:00 a.m. Most people, I believe, wake up sometime between 6:30 a.m. and 8:30 a.m. But regardless of when you
wake up in the morning, one of the first things that happens is that your body
temperature is increasing and that's just going to happen naturally. Some of it is going to be the consequence of your moving around a bit, but really the increase
in body temperature is one of the main triggers for why you woke up in the first place. That increase in body temperature
in turn causes an increase in the release of a
hormone called cortisol. Cortisol is often discussed
as a stress hormone, but it's not just associated with stress. It also enhances your immune system provided cortisol is
elevated at the right times, and the right time for
cortisol to be elevated is when you first wake up in the morning. That increase in cortisol is also going to increase metabolism. It's also going to increase
your ability to focus mentally and for you to move your body. So again, cortisol is often demonized and consider this bad thing. And indeed, you don't want cortisol to be chronically or consistently elevated throughout the day or night. But you do want cortisol to
reach its peak early in the day right about the time you wake up. One way that you can ensure that that cortisol peak
occurs early in the day right about the time that you wake up is to view bright light,
ideally from sunlight, within the first 30 to
60 minutes after waking. That's right, view bright sunlight within the first 30 to
60 minutes after waking. I'll get into all the caveats about what happens if you
wake up before the sun is out, what if you live in the
UK where there is no sun, or people claim there is no sun. Hate to tell you this, folks,
but there is sun in the UK. We'll talk about all that. But everybody, whether or not
you live in a cloudy place or a sunny place, whether or not there's
cloud cover or not that day, should really strive to get
bright light in your eyes, ideally from sunlight, within the first 30 to
60 minutes after waking. The reason for that is very simple. You want to trigger that cortisol increase to occur very early in your day, and you don't want that
cortisol peak to happen later, which is what will happen if you wait to get
outside and see sunlight. The reason for this is that you have a set of
neurons, nerve cells, in your eye. They're called
intrinsically photosensitive melanopsin cells, but you do not need to know that name. Those neurons respond
best to bright light, and especially right after
waking early in the day, they are best able to
signal to a set of neurons that reside over the roof of your mouth called the suprachiasmatic nucleus, which is a cluster of neurons that then sends a huge
number of other signals, electrical and chemical, out to your entire body that triggers that cortisol increase, provides a wake-up signal
for your brain and body, and sets in motion a timer for you to fall asleep later that night. So again, we're not trying to go into too much mechanism today. We are trying to really hammer on tools and I'll substantiate those tools just a bit with some mechanism. But here's what you do, or
at least here's what I do. I wake up in the morning and
I want to reach for my phone, but I know that even if I were
to crank up the brightness on that phone screen, it's not bright enough to
trigger that cortisol spike and for me to be at my
most alert and focused throughout the day and to optimize my sleep at night. So what I do is I get out
of bed and I go outside. And if it's a bright, clear day and the sun is low in the sky or the sun is, you know,
starting to get overhead, what we call low solar angle, then I know I'm getting
outside at the right time. If there's cloud cover
and I can't see the sun, I also know I'm doing a good thing because it turns out,
especially on cloudy days, you want to get outside and get as much light energy
or photons in your eyes. But let's say it's a very clear day and I can see where the sun is. I do not need to stare
directly into the sun. If it's very low in the
sky, I might do that because it's not going to
be very painful to my eyes. However, if the sun is
a little bit brighter and a little bit higher in the sky, sometimes it could be painful to look at. So the way to get this sunlight
viewing early in the day is to look toward the sun. If it's too bright to look at directly, well, then don't do that. You just look toward it,
but not directly at it. It's absolutely fine to blink. In fact, I encourage you to blink whenever you feel the impulse to blink. Never look at any light,
sunlight or otherwise, that's so bright that
it's painful to look at 'cause you can damage your eyes. But for this morning sunlight viewing, it's best to not wear sunglasses, that's right, to not wear sunglasses, at least for this
morning sunlight viewing. It is absolutely fine to wear
eyeglasses or contact lenses, so-called corrective lenses. In fact, those will serve you well in this practice or this tool because they will focus the
light onto your neural retina and onto those melanopsin intrinsically photosensitive
ganglion cells. If your eyeglasses or contact lenses have UV protection, that's okay. There's so many different
wavelengths of light coming from the sun and they are bright enough that they will trigger the mechanisms that you want triggered
at this early time of day. So try and get outside, ideally within the first
five minutes of waking or maybe it's 15 minutes, but certainly within the
first hour after waking. I want to share with you
three critical things about this tool of
morning sunlight viewing. First of all, this is not
some woo biology thing. This is grounded in the
core of our physiology. There are literally
hundreds, if not thousands, of quality peer-reviewed papers showing that light
viewing early in the day is the most powerful stimulus for wakefulness throughout the day and it has a powerful, positive impact on your ability to fall
and stay asleep at night. So this is really the
foundational power tool for ensuring a great night's sleep and for feeling more awake during the day. Second of all, if you wake
up before the sun is out, you can, and probably should,
flip on artificial lights in your internal home
environment or apartment or wherever you happen to live if your goal is to be awake, right? If you wake up at four in the morning and you need to be awake, well, then turn on artificial lights. Once the sun is out, however, once the sun has risen, then you still want to get
outside and view sunlight. Some of you will wake up
before the sun comes out. And if you're asking whether or not turning on artificial lights can replace sunlight at those hours, unfortunately, the answer is no. Unless you have a very special light, and we'll talk about what kind of light, the bright artificial lights
in your home environment are not, I repeat, are not
going to be sufficiently bright to turn on the cortisol mechanism and the other wake-up mechanisms that you need early in the day. The diabolical twist, however, is that those lights in
your home or apartment or even on your phone are bright enough to disrupt your sleep if you look at them too late at night or in the middle of the night. So there's this asymmetry in
our retinal, our eye biology, and in our brain's biology, whereby early in the
day, right around waking, you need a lot of light, a lot of photons, a lot of light energy, and artificial lights
generally just won't accomplish what you need them to accomplish. But at night, even a little
bit of artificial light can really mess up your
so-called circadian, your 24-hour clocks, and all these mechanisms
that we're talking about. So if you wake up before the
sun is out and it's still dark, please turn on as many
bright artificial lights as you possibly can or need, but then get outside once the sun is out. On cloudy days, you especially
need to get outside. I repeat, on cloudy days, overcast days, you especially need to get
outside and get sunlight. You just need to get more of it. Now, how much light and how
much light viewing do you need? This is going to vary
depending on person and place, literally where you live on earth, whether or not there's
a lot of tree cover, whether or not you're somebody
who has sensitive eyes or less sensitive eyes. It's really impossible for me to give an absolute prescriptive, but we can give some general guidelines. In general, on a clear day, meaning no cloud cover
or minimal cloud cover, you want to get this sunlight
exposure to your eyes for about five minutes or so. Could be three minutes one day, could be seven minutes the next day, about five minutes. On a day where there's cloud cover, so the sun is just
peeking through the clouds or it's more dense cloud cover, you want to get about 10
minutes of sunlight exposure to your eyes early in the day. And on days that are
really densely overcast or maybe even are rainy, you're going to want to get
as much as 20 or 30 minutes of sunlight exposure. Another key thing is do not, forget about, just don't try and get
this sunlight exposure through a windshield of a car or a window, whether or not it's tinted or otherwise. It takes far too long. It's simply not going to
trigger the relevant mechanisms. You would be standing there all day trying to get enough light into your eyes from the morning sunlight and by then the sun
will have already moved from low solar angle to overhead and it simply won't work
for all sorts of mechanisms related to your circadian
rhythm functions. So just don't try and do it through a windshield,
sunglasses, or a window. It's just not going to work. Get outside. If the weather is really bad or for whatever reason, safety reasons, you cannot get outside, well, then I suppose try
and get near a window. That would be the last, last resort. But you really want to get outside to get this sunlight exposure. Now, if you live in a part of the world where it's extremely dark and overcast or the weather won't let you outside or you live in a cave
or some other small box that does not allow any
natural light into it for whatever reason, well, then you're going
to need a replacement for that sunlight. And there are sunlight
simulators or daylight simulators that you can purchase. Those are quite expensive in general and therefore I suggest cheaper options that work just as well because they get just as bright. Things like ring lights that are sold in order for people to take
selfies and this kind of thing. A drawing LED tablet
will work pretty well. I actually have one of those and I put it on my desk all morning even though I still get
outside and look at sunlight first thing in the morning, again, also, especially, I
should say, on cloudy days. We do not have any affiliation to any ring lights or LED
lights or these panels. So we will provide a link to
a couple of different options if you want to explore
the various options. I don't know what people's
different budgets are. I don't know where people live. I just know that many
of our listeners live in locations throughout the world where, for instance, during the winter, it gets very, very dark, so they can't get sufficient sunlight. But get that morning light,
ideally from sunlight, and take into account
all the specific points that I've given you here. And, I should say, enjoy this practice. It's really nice to get outside
first thing in the morning and get this sunlight. In fact, when you start doing this, you'll notice that your body will start to feel more energized and it will feel more
energized more quickly. You'll actually start to notice this mechanism
kicking in each day, especially if you're paying
attention to your physiology. So enjoy this practice of getting outside. Yes, you can take your
morning beverage outside. Yes, you can take your dog with you. In fact, animals intuitively know to get this morning sunlight. They actually seek it out
at the right times of days. We human beings need to be told by podcasters and other people about the science that supports
these kinds of practices. Our pets apparently do not. But get outside alone or with somebody, with your kids, with your dog. However you go about this practice, make sure you do this practice at least 80% of the days of your life. That's right. If you miss a day, for instance, you're bedridden for a day, try and get next to a window. Let's say you are traveling, or for whatever reason, you are not able to get outside
first thing in the morning, well, then try to get twice
as much sunlight in your eyes, or I should say extend the duration of sunlight viewing in the morning for twice as long the following day. This is a slow, integrative mechanism that underlies this whole thing of wakefulness during the day and sleep at night due to sunlight viewing and if you miss a day, you can
make up for it the next day, but you have to get twice as much light or twice as much duration of light. If you really want to get technical and you really want to measure how much light is in your environment, you can download a free app,
something like Light Meter, and that will allow your phone to act as a bit of a light meter. It'll give you a pretty
accurate measurement of how many lux, which is
a measure of brightness, are in your environment in the morning. And in general, that's just
going to be a good tool for evaluating your environments. Here's what I suggest you do. Wake up in the morning, take Light Meter, point it at the brightest
light in your home, and take a measurement, and what you'll probably find
is it's about a thousand lux. Now go outside and if
there's some sunlight out and there's cloud cover, point it at the sky and press that button. You can actually hold it down and it'll give you a dynamically
updated lux measurement. And what you'll find
is like 5,000, 10,000, sometimes even 90,000 lux, even though you don't experience
it as so much brighter, and that's because an
indoor artificial light is very concentrated
over a small spatial area whereas the sunlight is very diffuse. But it's that diffuse,
very bright sunlight, that photon energy, that you really want that's going to set all the
rhythms of your brain and body in the proper way. Not just that cortisol peak, but it's going to trigger
proper metabolism, it's going to set a timer for you to be able to fall asleep
about 16 hours later, and on and on and on. And I should mention within
the on and on and on, it's also going to suppress any melatonin, a hormone that makes you sleepy that happens to be swimming
around in your bloodstream at the time you wake up. It does a number of other things too, including interact with
the adenosine system and kind of wash out some of the adenosine that might still be residual
if you didn't sleep enough. Fundamentally speaking, get
that morning sunlight viewing. I promise you will be
grateful that you did. It makes everybody feel
better, feel more alert, and it will greatly
assist with your ability to fall and stay asleep later that night. Before we continue with
today's discussion, we're going to take a brief pause to acknowledge our sponsor, Athletic Greens, also called AG1. I started taking Athletic
Greens way back in 2012. So I'm delighted that they've been a
sponsor of this podcast. Athletic Greens contains
vitamins, minerals, probiotics, digestive enzymes, and adaptogens. So it's got a lot of things in there. That's actually the
reason I started taking it and the reason I still take
it once or twice a day. It essentially covers all
of my nutritional bases. And the probiotics in
particular are important to me because of the critical importance of what's called the gut-brain axis, that is neurons and other
cell types in the gut, in the digestive tract, that communicate with the brain and the brain back to the digestive tract in order to control things like mood, immune function, hormone
function, and on and on. Whenever somebody has asked me what's the one supplement
they should take, I always answer Athletic Greens. I gave that answer long
before I ever had this podcast and it's the answer I still give now for all the reasons that I
detailed just a moment ago. If you'd like to try Athletic Greens, you can go to athleticgreens.com/huberman to claim a special offer. They'll give you five free travel packs that make it really easy
to mix up Athletic Greens while you're on the road, plus a year's supply of vitamin D3K2, which are also very important for a huge number of bodily
factors and brain factors that impact your immediate
and long-term health. Again, that's athleticgreens.com/huberman to claim that special offer. Okay, so now we're still focusing on this early part of the
day when you've woken up, the first hour or so after waking. And we can go to our list of
other levers and tools, right? We have light and dark. We already talked about light
and sunlight in particular. We've got temperature, food, exercise, caffeine, supplements, and digital tools. Now, once you've woken up and
you want to be awake, okay? So this is likely to be early in the day if you're following a
more standard schedule. You will also want to
leverage not just light, but temperature as a tool. If you are inclined, it would be wise to try and increase your
core body temperature a bit more quickly than it would otherwise if you were to just, you
know, shuffle around outside, get your sunlight, maybe read a little bit, et cetera, and there are two main
ways you can do that. The first way is to get into
cold water of some sort. So this could be a cold shower of anywhere from one to three minutes. This could be an ice bath
if that's your thing. It could be a cold tub, or if you own a cold tub that's specifically designed
for deliberate cold exposure. Get under some cold water. That will certainly wake you up. And if you've ever jumped into cold water or had a cold shower, you know it really wakes you up because you release
adrenaline, epinephrine, from both your brain and body, the body from your adrenals and your brain from a
little cluster of neurons called locus coeruleus. Again, the names don't matter. One to three minutes of cold
water exposure will wake you up because of that adrenaline release and, and I want to highlight the and, it will serve to increase
your core body temperature. That's right, your body and brain interact as a bit of a thermostat system where if you put something cold
on the surface of your body, your brain, a little cluster of neurons in the so-called medial preoptic area, act as a thermostat and say, "Ah, the external of my body is cold and therefore I'm going to heat up my core body temperature." So it's a little bit paradoxical. People think, oh, if you get
into cold water or an ice bath, your body temperature is going to drop. And indeed, that's true if
you stay in for a while, but if you just get in for
about one to three minutes, or under the cold shower
for one to three minutes, your core body temperature will increase. So then when you get
out of that cold water, your body temperature is
increasing at a rate, at a slope, that's steeper than it would otherwise and you're going to feel more alert. It also has the advantage of increasing not just adrenaline, but dopamine, which is a molecule involved in motivation, focus, et cetera. So this is great for waking up. So we've got sunlight, we've got temperature
triggered by cold water, and we have exercise. One of the best ways to increase your core body
temperature early in the day is to do exercise. Now, some of you might choose to do your full-blown workout for the day first thing when you
wake up in the morning, I would say the best time to exercise, at least what the research points to, is immediately when you
wake up in the morning or three hours after waking
or 11 hours after waking. But that's really getting
down into optimization for sake of muscular
strength and grip strength and it's very hard to give
a strict prescriptive. Here's what I suggest. If you want to be alert early in the day and you want to sleep great at night, get that bright sunlight,
get into some cold water, and if you don't want to
get into some cold water, try and get some movement. It could be a walk. So you can get your sunlight exposure while you're taking a walk
first thing in the morning. It could be a light jog. It could be skipping rope. These days, I skip rope for
about 10 minutes or 20 minutes while looking at the sun. So I'm trying to layer
in these different things for waking up. And then I take a cold shower afterwards. This is what I've been doing as of lately, but I don't do that all
year long necessarily. Or some of you are going to
be working out mid-morning. I sometimes do that. But try and get your core
body temperature increased first thing in the morning, and a great way to do that
is with the cold water and/or with exercise. And again, it doesn't have
to be your full-blown workout for the day if you're doing workouts consistently, which I hope everybody is because everybody really should exercise at least, I believe, five or six, or maybe even seven days a week. For me, it's six days
a week, sometimes five, rarely is it seven. So get that exercise or even just a modest amount of movement, walking, jogging, skipping rope, some light calisthenics. That will further increase
your core body temperature and help you feel more awake. Then we have the category of caffeine. And again, we're just talking about this early part of the day, and you might be saying, "Wait a second, I thought this was an episode
about tools for sleep." Well, everything that
we're talking about doing in these first 60 to 90 minutes of the day really set in motion a
wave of biological cascades that carry through the entire day and into the evening and into the night and really do serve to optimize sleep. So just hang in there with me. And for those of you that are interested in focus and attention,
your ability to learn, all of these tools and practices are going to greatly
enhance those as well. So the next category of tool for use early in the day is caffeine. Caffeine is a very important
compound to think about. I do realize that some people
who are prone to anxiety, especially panic attacks, anxiety attacks, might avoid caffeine entirely. That's absolutely fine. You do not have to drink caffeine. So what I'm about to describe are ways to leverage caffeine use to optimize sleep and wakefulness if you are comfortable with
caffeine, if you like caffeine, I happen to love caffeine. I like it in the form
of coffee or espresso or yerba mate tea, in particular non-smoked
varieties of yerba mate tea. Non-smoked because the smoked
varieties seem to carry some carcinogenics, some
cancer causing risk. There's increasing data on that. So non-smoked varieties of yerba mate. So caffeine is something that a lot of people
consume early in the day. How much depends on your tolerance, and there's a lot of
individual variability here. Again, caffeine is an
adenosine antagonist, or effectively works as
an adenosine antagonist and limits sleepiness. I highly recommend that everybody delay their caffeine intake for 90 to 120 minutes after waking. However painful it may
be to eventually arrive at that 90 to 120 minutes after waking, you want, and I encourage you, to clear out whatever residual adenosine is circulating in your system in that first 90 to
120 minutes of the day. Get that sunlight exposure, get some movement to wake up, and then, and only then,
start to ingest caffeine because what you'll do if
you delay caffeine intake until 90 to 120 minutes after waking is you will avoid the
so-called afternoon crash. And you may still get a
little bit of dip in energy in the afternoon, but it's not going to
be that massive crash. I've talked about the
reasons for that crash on previous episodes. But if you delay your caffeine intake 90 to 120 minutes after waking, you are doing yourself a great
service towards wakefulness and to avoid the crash. And the afternoon crash has
another liability to it, which is typically people will emerge from that afternoon crash
either grumpy or groggy and then they'll lean into
drinking more caffeine, which can then disrupt their sleep. So wait 90 to 120 minutes
after waking in the morning to drink caffeine. And if you drink caffeine at
any point throughout the day, really try and avoid any caffeine, certainly avoid drinking more than a hundred milligrams
of caffeine after 4:00 p.m. and probably even better to
limit your last caffeine intake to 3:00 p.m. or even 2:00 p.m. And for many people,
shifting that caffeine intake from immediately after
waking in the morning to 90 to 120 minutes gives them a much longer arc
of energy throughout the day and they don't feel the need to drink more caffeine
later in the afternoon. If you do drink caffeine
later in the afternoon, really try and limit the
total amount or drink decaf. Certainly keep the total amount to less than a hundred milligrams if you are interested in getting into the best possible sleep. And I say this knowing that
many people, including myself, can drink a double espresso with 200 milligrams of caffeine or more at 5:00 p.m. or even
6:00 p.m. or after dinner and still, quote,
unquote, fall asleep fine or still sleep fine. However, there are terrific data, Matt Walker and I talked about this, and there are more and
more papers all the time that point to the fact that
caffeine intake late in the day, after 4:00 p.m. that is, can really disrupt the
architecture of your sleep. So you might think you're sleeping well, but you're not sleeping
nearly as well as you could if you avoided caffeine
in those afternoon hours. Now, some of you might be doing
your main about of exercise first thing in the morning and you want your caffeine
before that about of exercise. In that case, I say, go for it. Drink your caffeine, do your workout right after waking up. I don't have a problem with that. You will find, however, that you're going to get an
early afternoon dip in energy and that dip in energy is
going to be substantial because it's going to be a dip in energy that naturally follows that
workout from the morning. So it's dependent on temperature, and it's going to be related to the elimination of that
adenosine blockade by caffeine. So you're getting a
kind of a one-two punch on your energy levels by taking a lot of caffeine and
exercising early in the day. You can sort of expect that you're going to get a drop in energy in the early afternoon. That's okay if that works for you, but just know that delaying that caffeine 90 to 120 minutes after waking would be the ideal scenario
most days and most scenarios. All that said, I
absolutely respect the fact that people have different work schedules, kid schedules, et cetera. So if you want to do some
or none or all these tools, that's really up to you. I'm just providing them to you in the simplest form that I
can possibly provide them. Now, the other lever or tool that you have available to you is food. Not just what you eat, but when you eat. And it turns out that if
you eat early in the day, you support a biological clock mechanism that will make you more
alert early in the day. That said, many people choose to fast in the early morning hours of the day or in the first part of the day. I'm one such person. I generally don't ingest any food until about 11:00 a.m. or 12 noon. Sometimes I'll have a protein shake. Sometimes I'll have some almonds. Sometimes I'll have breakfast. If people are meeting
for brunch or breakfast, I will have breakfast for social reasons every once in a while. But most of the time I don't
eat until about lunch time. However, some people are really hungry when they wake up in the morning. Just know that if you
eat early in the day, you are further triggering
an increase in metabolism and in temperature that
will make you more alert. So you don't have to eat early in the day, but you can start to see how these different tools layer together. Sunlight viewing, exercise,
cold water, eating. Many of them are converging
on the same mechanisms. In fact, when you drink caffeine, there's also a small
increase in body temperature due to the adrenaline
increase that it stimulates. So all of these things can be
layered on top of one another or you can use them individually or think about them individually. Now, food is an interesting lever or tool because it's not just about when you eat, but it's also about what you eat. And I've talked a lot
about eating for energy and what that means in
terms of caloric energy versus neural energy, et cetera, in previous podcast episodes. We're not going to focus on that now because, frankly, to
get into a description of whether or not somebody
should eat fruits or vegetables or animal proteins or dairy,
et cetera, early in the day, that's very nuanced. What you eat for your breakfast, or if you choose to not eat breakfast, is really up to you. All that said, if you
eat a very large meal, it doesn't matter if you
slept terrifically well 10 hours the night before or if you are about to go to sleep or if it's the middle of the afternoon, if your gut is full of food, there's just a large
volume of food in your gut, it's going to divert a lot of blood and other critical resources away from other organs of your body, in particular, your brain, and you're going to be sleepy
after eating a big meal. So this is sort of a duh, but I think oftentimes in the discussions about what to eat for energy, people neglect to consider food volume as a strong parameter or
variable in that discussion. So if you eat a huge breakfast, it's likely that you are going to be tired immediately after eating that breakfast unless of course you exercise
very hard prior to that and you metabolize all
that food very quickly. So it's up to you whether or not to eat first thing in the morning or not. But if you do eat in the first
few hours of the morning, just understand that you are setting or you are helping to set a food entrained, as it's
called, circadian clock. Light, temperature, timing of food intake, movement and exercise, all of these things literally
funnel in in a neural sense, they funnel into this thing
that we call the circadian clock and they let that clock,
that set of neurons, predict when you are likely
to be eating and active and viewing sunlight the next day and the next
day and the next day. I say all this because there
are some beautiful studies, and I'll highlight one, again,
in the show note captions, that show that if people
are having a hard time waking up in the morning, one of the things they can do is maximize sunlight viewing,
exercise in the morning, drink caffeine. Although, again, I support the idea that that would best be done about 90 to 120 minutes after waking. Eating some food in those
early morning hours, et cetera, et cetera. You can layer in multiple levers or tools in order to be more alert. And that's what these levers
and tools are really there for in this sense of what
we're talking about today, which is optimizing sleep. Yes, they will make you more alert. Yes, they will provide some
adrenaline and dopamine, for instance, the cold
water, et cetera, et cetera. But the reason we're
talking about these things in the context of sleep is that they start to give your body some predictable autonomic timing. What is predictable autonomic timing? Well, your autonomic nervous system is the components of your brain and body that cause wakefulness and sleepiness and you can start to
create some predictability in that autonomic timing. You can start to do things
that really make it such that you naturally wake
up at six in the morning or five in the morning. That's right, if you're somebody who naturally is a night owl, who likes to stay up
until two in the morning and sleep until 10:00 a.m., and you now have a job or
you have to go to school or you have a partner
that likes to get up early and go to sleep early, well, you can make that happen and you can make that
happen pretty painlessly if you take a week or so and go to sleep 30 minutes or
an hour earlier each night, set an alarm and wake up 30 minutes or
an hour earlier each morning until, of course, you're waking up at the time you want to wake up, and then even in that groggy state, get some exercise, get
some sunlight viewing. If the sun's not out, turn on those bright artificial lights. Have some breakfast, even
if you're not hungry. In fact, for those of you
that engage in shift work because you have to, or travel and you're jet lagged, one of the quickest ways to
shift your circadian clock and get onto the local schedule is to eat on the local schedule. So what all these tools do is
they really set up a cascade. Think of it as kind of a
wavefront of wakefulness and focus throughout the day. It'll take you through
the middle of the day and the afternoon stage we'll
talk about in a few minutes, but really they take you to this period that is about 5:00 p.m.
until your bedtime. I realize some people are
going to bed very early, like 8:00 p.m. or 9:00 p.m.,
which to me seems very early, but very few people go to
sleep at 5:00 p.m. right? Unless you're doing that for
shift work or other reasons. But from 5:00 p.m. until bedtime
is really a critical period in which you need to
leverage particular tools in order to get and stay asleep optimally and to be able to sleep through the night. So really there are three critical periods throughout each 24-hour cycle. And during each of those critical periods, you're going to want to do as many specific things as you can to optimize your wakefulness and focus and mood throughout the day and your sleep at night. The first critical period is the one that we've been
talking about up until now. Things like morning sunlight viewing, caffeine 90 to 120 minutes after waking, exercise, and so on. We can call that critical period one and it really encompasses the
time from which you wake up until about three hours after waking. Although, I should just mention 'cause there are always
those people that say, "Wait, I wake up at 4:00 a.m. and the sun isn't out until 8:00 a.m.," okay, so it might be four hours. But really it's those early
morning hours of your day once you're awake. The second critical period is the time throughout
the day and afternoon leading into evening. So you may ask what are
the things that you can do throughout the day, the middle of your day and into the afternoon and evening hours, that are really going to set you up for the best possible
sleep later that night. Well, there are a few dos
and there are a few don'ts. First of all, be careful about ingesting
too much caffeine throughout the middle of the day. That's kind of an obvious one for the reasons that we
talked about earlier. Second of all, if you are a napper, and I raise my hand now, for those of you listening, I'm raising my right
hand because I love naps. I've always loved naps. Nowadays I do NSDR or
a Reveri sleep hypnosis almost every day. And I tend to do that, as I mentioned, in the early afternoon hours if I'm feeling kind of sleepy, because even though I optimize my caffeine intake timing, et cetera, I tend to get a little
sleepy in the afternoon. Most people get a little
sleepy in the afternoon. Some of that is related to hitting that peak of body temperature. And you might think, wait, I
thought high body temperature is associated with alertness, and it is, but right as you crest
that high body temperature and your body temperature starts to drop, there's a tendency to
be a little bit sleepy. So some of you might opt to
take a nap in the afternoon. Should you nap, should you not nap? That's a question that I get asked a lot and that I asked Dr. Matthew Walker when he was a guest on this podcast. Here was his answer and
here's what the data support. It is fine to nap in the afternoon, but don't nap so late in
the day or for so long that it disrupts your ability to fall and stay asleep at night for your major sleep about, okay? So naps are fine, but don't sleep so long during the day or too late in the day that it disrupts your ability
to fall and stay asleep. I should also say you do not have to nap. It's kind of an interesting phenomenon that happens on these
podcasts and on social media where we'll talk about naps and the fact that naps are great, but don't make them
longer than 90 minutes, but then all the non-nappers
get really worried. Like, wait, am I supposed to nap? I don't like naps. I wake up groggy. You do not have to nap. In fact, if you can make it through your whole day without napping, great, more power to you. But if you do nap and you
find that naps serve you well, keep those naps shorter than 90 minutes for reasons related to
ultradian cycles and so forth, and make sure that you don't
nap too late in the day that you are then staying
up too late at night and having a hard time
waking up the next morning. I will say that for a lot of
people who do not like naps or that find they wake up
really grumpy from naps or groggy from naps, I encourage you to try the Reveri app, try an NSDR script, try yoga nidra. Try something of that sort for anywhere from 10 to 20 to 30 minutes. I tend to do this every day now. I'll just lie down, and I love yoga nidra, I love NSDR scripts, I love using the Reveri app. In particular, the
portion of the Reveri app that gets you better at sleeping. It really is beneficial for me because it serves as very replenishing while I'm doing that hypnosis, but it's also gotten me much better at falling and staying asleep and falling back asleep in
the middle of the night. So this critical period throughout the day is one in which most people
are doing a lot of stuff. They're emailing and picking up kids and they're exercising
and they're commuting and doing all sorts of things, taking phone calls and Zooms, et cetera. But if you can get that
period of deep relaxation through a nap or NSDR, that's going to serve you well. Try not to drink too much caffeine, certainly no more than a
hundred milligrams of caffeine, after 4:00 p.m if your goal is to fall asleep
at a reasonably normal time. And for those of you that
exercise in the afternoon, understand that if you
exercise very intensely, so this might be weight
training or running or some other very intense exercise, typically that's going to further increase your body temperature. Makes sense, right? Based on everything we know about metabolism and body temperature. And it's going to so-called
delay your circadian clock. It's going to make it such that you want to fall
asleep a little bit later, maybe even a lot later. So if you're exercising in
the afternoon or evening and that's the only time you can exercise or that's the time that
you prefer to exercise, great, but be careful about
ingesting too much caffeine in order to get the
energy to do that exercise 'cause that caffeine
will disrupt your sleep and just know that you are
delaying your circadian clock. You are making it such that you will naturally
want to go to sleep later and wake up later. Contrast that with if you
exercise early in the day, say, immediately after waking up or in the first zero to
four hours after waking, in most cases, that's not going to shift your circadian clock much. And toward the end of the episode, we'll talk a little bit
about forced exercise prior to wake-up times. That doesn't mean doing
exercise in your sleep. That means deliberately setting an alarm and getting out of bed much earlier than you naturally would. That turns out to be a very potent tool to so-called advance your circadian clock. So we can talk about that a
little bit later in the episode. But this critical period,
too, in the middle of the day is when you're going to want
to leverage specific tools, and we've talked about those: limiting caffeine intake; being mindful of the
clock-delaying effects of exercise; the fact that, also,
if you're going to nap, you don't want to nap too
long or too late into the day otherwise you'll disrupt
your nighttime sleep. So this critical period two, or second critical period, I should say, during the middle of the day is a time in which you should
be doing certain things and avoiding doing certain things. So that raises the
question of whether or not you should also be getting a lot of light, in particular, sunlight,
throughout the day. Now, that's something that
hasn't been explored too much in the literature until recently when Dr. Samer Hattar who's the director of
the chronobiology unit at the National Institutes
of Mental Health, decided to do a number of experiments exploring the effects of light on mood and other aspects of brain
function and body function when that light is delivered
not just in the morning, which is great for us, but also throughout the day. So should you be looking at sunlight or bright artificial
lights throughout the day? Now, on the face of it, you might just think, yes,
you know, sunlight's great. Provided we're not getting a sunburn and we're not staring at the
sun and damaging our eyes, we should get as much
sunlight as we possibly can. In fact, we talked about this
in the episode on hormones about how getting light
onto as much of our skin as we can throughout the day can really help in the production of testosterone and estrogen
in both men and women in healthy ways that
improves mood and libido and all sorts of things that
are associated with wellbeing. However, because light is
such a powerful stimulus for controlling the timing of your sleepfulness, or
sleepiness, I should say, and wakefulness, we might want to be cautious about how much light we are
viewing in the afternoon, in particular, in the
early evening hours, right? Well, turns out it's
not so straightforward. Viewing, so sunlight to the eyes, sunlight in the late afternoon and evening hours, so again, depends on time of year, depends on location that
you happen to be in, but getting some sunlight in your eyes for, again, maybe five
or 10, maybe 30 minutes, depending on how much
cloud cover there is, doing that in the afternoon serves an additional beneficial purpose, which is you protect or you
inoculate your nervous system against some of the negative effects of bright artificial light or even dim artificial
light in the nighttime hours between 10:00 p.m. and 4:00 a.m., which is really critical period three. And we'll talk about what
to do and what to not do during critical period three
of every 24-hour cycle. But to make it very clear
what I'm saying here, get that morning sunlight in your eyes, but also get some sunlight in your eyes in the late afternoon and evening hours when the sun is at
so-called low solar angle, when it starts to descend in the sky. Again, you don't have to
stare directly at the sun, although if you can catch
a nice, beautiful sunset, go for it. But as the sun starts to descend, it triggers those same neurons in your eye that communicate with
your circadian clock, but it communicates with
a different component or different compartment
within the circadian clock. That circadian clock
is not just one thing. It's multiple things. And you have what are
called morning oscillators and evening oscillators. And to make a long story short, the tool that I'm describing
of looking at the sun in the late afternoon and evening, again, blinking is fine, don't stare at the sun, but getting that sunlight in your eyes in the late afternoon and evening signals to that clock
that it's evening time and that sleep is coming. It also serves as a second
anchor or reference point for your body and your brain
to know where it is in time. Remember back to the
beginning of the episode when I said your brain and
your body and all your organs are locked inside this skin and this skull and they don't know what's
going on in the outside world. Well, that morning sunlight viewing and the other things you do
during critical period one, those provide one strong set of signals that it's wake-up time
and time to be alert and time to be focused. And then in the evening, by getting sunlight in your eyes again, in particular, sunlight that comes from low solar angle sunlight, well, that provides a second stimulus or a second reference point that tells your brain and
body, "Hey, it's evening. The sun is descending." Now, you might say, "Wait, how does the brain
and these neurons know the difference between morning
light and evening light?" It turns out has to do with the particular wavelengths of light that are present in
morning versus evening. It's an incredible mechanism. And you are probably
familiar with the fact that when the sun is directly overhead, it's really bright white and yellow and the sky's often blue, and if there's cloud cover, it just comes through as
a bunch of bright light, well, next time you're out in the morning, take a look at what a sunrise looks like. There's a lot of yellow-blue contrast, and those yellow blues signal important specific sets of
cells in your eye and brain that it's morning. In the evening, you're also
going to see yellow and blue, but the ratio of yellows
and blues has now changed and you also see some oranges, and in a really brilliant
sunset, you'll see some reds. If you haven't noticed this already, you'll really want to look for this. It's really kind of fun
and cool to look at. Well, those yellows and blues and oranges that you see in the evening sunsets, those signal to your brain
and body that evening is there and that nighttime is coming and they're really establishing a second reference point or
wavefront of biological signals that are going to optimize
your nighttime hours and your transition into
really terrific sleep. So now let's talk about what I'm calling
critical period three of each 24-hour cycle. So this would be the period
of time of late evening, So it might be 6:00 p.m. for some, depending on when you go to sleep, or 7:00 p.m. extending into the hours in which you decide to get
into bed and go to sleep and then throughout the night. There are a number of things that you're going to want to do and there are a number of things that you are going to want to avoid doing in order to optimize your sleep. First of all, you're
going to want to avoid bright artificial lights of any color. Yes, of any color. We haven't talked a lot
about blue blockers, you know, lenses that
block blue wavelengths or short wavelengths of light. I don't have anything
against blue blockers. In fact, many people find that
blue blockers provide them some relief from headache
and some eye strain if they wear blue blockers throughout the day and certainly at night. But you don't need them, and even if you do wear them, you will find that if
lights are very bright, doesn't matter if it's a blue light, a yellow light, or a red light, those bright lights will
wake up your brain and body. They will activate the same mechanisms that were activated early
in the day by sunlight. However, and here's the
really diabolical twist, I mentioned this earlier, but the diabolical twist in the way that your brain
and body respond to light is that early in the day, in the morning hours, you
need a lot of bright light, ideally from sunlight, to be very alert and to wake up, but in the evening hours
and nighttime hours, it takes very little
light, very few photons, in order to wake up your brain and body and to disrupt your circadian
clock and disrupt your sleep. So what that means is that
once the sun goes down, which, of course, is going to happen at different times of year
in different places on earth, but once the sun goes down, you would be wise to
try and dim the lights in your indoor environment
most days, right? I realize some nights you're
going to throw a party and have people over. You might not want to dim the lights. Some nights you're going to go out, you might view a lot of bright lights. But most nights of your life, you're going to want to dim the lights in your internal environment. And ideally, the lights that you do use you would place low in
that physical environment. So you would try and
not use overhead lights, but rather rely on desk lamps or lights even placed low to the
floor, even on the floor. If you are going to use light at night, and most people do, I would encourage you to use
as little artificial light as is required to carry
out the activities you need to require safely. That could be studying, in which case you might
need a little bit more light in order to read or study. If you're watching a television show or you're watching
something on your computer, dim that screen way, way down, as dim as possible while
still, of course, being able to view what you need to view. Even better, I should say, ideally, you would use candlelight
and/or moonlight. Now, some nights the moon is really bright and you actually can use moonlight to go about your usual activities. Moonlight might seem very, very bright, but, actually, moonlight is
fairly low light intensity, and candlelight, which
can also seem very bright, actually is very low light intensity. If you're sitting across a table with some candlelight there and it's a really bright candle, chances are it's only
about three to 10 lux, which is very, very little light energy compared to, say, an artificial desk lamp or an overhead light, which is going to be in the area of anywhere from a
hundred to a thousand lux. So candlelight is fine. Of course, be cautious with open flame, but candlelight is fine. Moonlight is fine. Dimming artificial lights is fine provided they're dimmed way, way down. And again, try and avoid using
overhead artificial lights. The absolute worst lights are going to be overhead
fluorescent lights of the sort that you would
have in the supermarket or that you would see at a gas station or something of that sort. And I confess, there are times
in which I'm driving home and it's late at night and I
want to be able to get to sleep and I'll need to stop at the grocery store or a gas station or something like that, I've actually put on sunglasses at night in order to avoid getting that bright light exposure at night. Although that's a little bit extreme, I have done that from time to time because that bright light exposure will absolutely quash, it will eliminate, any melatonin that
happens to be circulating in your brain and body. Now, melatonin, a lot of people
think of it as a supplement, but melatonin is naturally released as the evening comes about
and into the nighttime hours. It's the hormone that
makes you feel sleepy and allows you to fall asleep. So viewing bright light in the late evening
hours and nighttime hours is really not good for your sleep quality and your ability to fall and stay asleep. So for most people, a simple rule of thumb is going to be avoid bright
artificial lights of all colors, and in particular, overhead
bright artificial lights, between the hours of
10:00 p.m. and 4:00 a.m. That's right, between
10:00 p.m. and 4:00 a.m., avoid those bright artificial
lights as much as possible. Use only as much light as
is absolutely necessary in order to carry out the
routines and activities you need to carry out safely. I should mention that the reason overhead
lights are problematic is the same reason why
sunlight is so great early in the day, which is that the cells,
that is, the neurons, that can wake up your brain and body through activation of the circadian clock reside mainly in the bottom half or 2/3 of your neural retina and the way the optics of your eyes work is that the cells on the
bottom half of your eye view the upper visual field. So this is a beautiful adaptive mechanism that allows these cells to respond to overhead light from sunlight in the early part of the
day and throughout the day. But in the evening, if you have
bright artificial lights on and those bright artificial
lights are overhead lights, it's going to more closely mimic what sunlight does in the evening time, and that turns out to be a bad thing if your goal is to eventually go to sleep. So again, do like the Scandinavians do. Use lights that are set
low in the room at night, and if you really want to
optimize your sleep-wake cycles, I suppose you could also do the
opposite throughout the day. You could really emphasize the use of bright artificial lights and sunlight that comes from above. And of course, sunlight
always comes from above. But if you're working in
a given office environment and, you know, it's 2:00 p.m. or 3:00 p.m. and you want to be as awake as possible, really crank up the overhead lights. And then in the evening, which is this critical period
three that we're referring to, really try and dim those
lights or have them off or just rely on candlelight or moonlight from the hours of about
10:00 p.m. until 4:00 a.m. Our good friend Samer Hattar, who's been on this podcast before, Samer is director of
the chronobiology unit at the National Institutes
of Mental Health, well, he's absolutely obsessive
about this light stuff and avoiding light at night. In fact, he lives in what I sort of joke is like a cave at night. From 9:00 p.m. until 5:00 a.m., which is really his kind of sleep cycle, he has his house so dark that you'd be lucky to be able to find a spoon in the kitchen. In fact, you'd be lucky to find your way down
the hallway if you're me. But in any case, dim the lights. Turn them way, way down. It will serve you well. It will make it much easier for you to get sleepy and stay
sleepy and fall asleep and stay asleep throughout the night. Now, not to depart from
this critical period three, but if you recall, viewing
that afternoon light, the low solar angle light as the sun is heading down in the sky, so it could be sunset or what I call circa
sunset, around sunset, well, doing that is going to slightly, but not completely, offset
any of the negative effects of viewing artificial light at night. So I don't want to give
people a pass here, but let's say you know that you're going to watch
some Netflix at night or you're going to be up late studying and yet you still want to be
able to fall and stay asleep. Definitely make sure you
see that evening light. There's a great study. We'll provide a link to this study, which showed that if people
view evening sunset light or evening sunsets or sunlight right around
the time of sunset, it really serves to
inoculate or offset some, again, some, not all,
of the negative effects of artificial light between the hours of
10:00 p.m. and 4:00 a.m. Now, that's light. But as you recall, we also have this tool
related to temperature, and you're probably not
going to be surprised that the way to leverage
temperature in the evening is the exact opposite of the way that you want
to leverage temperature early in the day. Early in the day, temperature increases from cold showers or exercise,
et cetera, wake you up. What that means is that taking
a cold shower late at night is probably a bad idea. Rather, taking a nice hot bath or a sauna, you might think would heat up your body, and indeed, that's what happens if you stay in a very long time, but if you do hot tub or a hot bath or a sauna in the evening, and you don't stay in for
more than 20 or 30 minutes and you get out, you take maybe a cool-ish
shower or a warm shower, then what happens is there's
a compensatory cooling off of your core body temperature for the reasons we discussed earlier, and your body temperature will
drop by one to three degrees and it will make it much
easier to get into sleep. So if you're somebody that enjoys hot baths,
hot showers, or hot tubs, evening and nighttime is going to be the best time to do that if your goal is to facilitate sleep. Similarly, you should try and make your sleeping environment
pretty cool, if not cold. Now, that doesn't mean you need to be cold while you're asleep. You can get under as many
blankets as you need, but it's a good idea to make
your sleeping environment cool. In fact, drop the temperature
in that sleeping environment by at least three degrees and you'll be happy that you did. Now, some people rely on
things like Eight Sleep. I use that. One of these controllable
temperature mattress covers. Other people would simply do this by putting a fan in the
room or opening a window. Again, depends on time of year, depends on technology,
depends on budgets, et cetera. But you're going to want to sleep in a relatively cool or
cold sleeping environment and then layer on the blankets
as needed to stay asleep. And I say as needed
because one of the things that you're going to do in your sleep, or if you happen to wake up, is if you're too warm, you're
going to put a foot or a hand out from under those blankets. And the reason for doing
that is very logical once you understand the mechanism. You have special portals, you essentially have ways of passing heat, excuse me, in and out of your body primarily through the palms of your hands, the upper half of your face, and the bottoms of your feet through so-called glabrous skin. This was covered in the
episode with Dr. Craig Heller from the biology department at Stanford. If you lower the temperature
in your sleeping environment, so lower the temperature in that room or use a controllable mattress
cover that can cool down like Eight Sleep or
something of that sort, it's naturally going to make
your sleep environment cooler, and if you're too warm under the blankets, all you have to do is
extend a hand or a foot out from under those blankets. Whereas if the sleeping
environment that you're in is too warm, there's very little you can do to cool off besides push off those blankets. So for instance, if you're too warm and you're waking up in
the middle of the night, which is what happens if you get too warm, you'll push off those blankets. But if the room is too warm, well, what are you going to do? You'd probably have to put
your hands into some cool water or take a coolish shower or something for a couple of seconds. That's not very practical. Better to just keep the
sleeping environment cool. I'm not a big fan of
people putting socks on while they sleep, or I should say, I'm not
a fan of putting socks on while I sleep, because that eliminates
this glabrous skin portal on the bottoms of one's feet. So for those of you that have heard, you know, wear socks while you sleep, that works great for people that tend to run too cold while they sleep and wake up because their feet get cold, but if you're somebody who wakes up in the middle of the night, chances are you're waking up because you're getting too warm and the best thing that you could do is to cool or lower the temperature in the room that you're sleeping and not wear socks, get under as many blankets
as you need to fall asleep, and then across the night, you'll naturally just
move a hand or a foot or all hands and feet out
from under those blankets to cool off because of the relationship
between temperature and sleep. That is, dropping your
core body temperature one to three degrees gets you into sleep and
helps you stay asleep. So let's say you do
exercise late in the day and you're finding yourself
very alert in the evening and you need to fall asleep, or let's say you've exercised and you needed four cups of espresso in order to do that exercise. Well, there are a few
things that you can do to try and bring your nervous system down into more state of calmness, and you can do that also by lowering your
core body temperature. One of those I already
talked about before, taking a nice hot shower or a hot bath and then getting out and cooling off will decrease your body temperature. Maybe not enough to get you into sleep if you have a ton of
caffeine in your system. But again, you can use this
mechanism of temperature shifts to wake up or temperature shifts to fall asleep in ways that really can help you overcome some of the irregularities
in your sleep-wake cycle and exercise cycle, et cetera. Because, of course, nobody's perfect. Some days we end up having
to workout in the afternoon or we'll miss the workout entirely. Other days, we end up
having that cup of coffee in the afternoon with a friend and then we have a hard
time falling asleep. So you can use these tools not just in their optimized form, you know, being absolutely
obsessive and compulsive about exactly when you
do each of those tools. That would be wonderful,
but life happens as they say and some days you're going
to feel too alert at night and you want to fall asleep, or you've got to get up
especially early the next morning and you're not somebody who normally goes to bed at 10:00 p.m. Well, that's when a something
like a hot bath or a sauna can really benefit you because it can adjust your
temperature rhythm accordingly. I would be remiss if I
didn't touch on alcohol and CBD and THC. I always get questions about these. And I should say, of course, many places, but not all, THC is illegal. Although, there are medical uses and in some places, it's decriminalized, other places it's legal. Alcohol, of course, is consumed almost as frequently as
caffeine is consumed. I personally don't drink alcohol. I don't have anything against it per se. I just don't tend to enjoy it. One of the reasons I don't enjoy it is if I drink alcohol,
I simply fall asleep. So that doesn't really accomplish any of the things that I
really want to accomplish because the sleep that one
gets after drinking alcohol is greatly disrupted sleep. Hate to break it to you,
but that's the truth. And when Dr. Matt Walker
came on this podcast, he said exactly the same thing. While THC and alcohol do
help some people fall asleep and maybe even stay asleep, the architecture of
that sleep is suboptimal compared to the sleep they would get without alcohol or THC in their system. So I'm not here to tell you
what to do or not to do. I'm certainly not the substance police. That's not my role. I'm just reporting to you the biology. If your sleep is not restoring you to the extent that you feel it should, or if you are regularly
relying on a drink or two in order to fall asleep, or THC in order to fall asleep, that is disrupting your
total pattern of sleep. However, I do realize that nowadays a lot of people
are relying on THC and/or CBD, especially edible forms, in order to fall and stay asleep. And, you know, we can
just acknowledge the data. It does seem that there's
an anxiety lowering effect of some of those compounds that do help people who have a hard time
falling and staying asleep because of reasons related to anxiety. Although, in a moment, we'll talk about some supplements
and supplement protocols that can also assist in the
ability to fall and stay asleep and that can adjust anxiety and that do not seem to
disrupt sleep architecture in negative ways and, in fact, can enhance
the depth and quality of sleep architecture. Okay, so you've done everything
correctly up until now. You got your morning routine
from critical period one. You've got your afternoon routine. You saw some sunlight in the afternoon. You avoided caffeine in the eight hours or 10 hours before bedtime. You're not drinking alcohol. You've cooled down the room. You're doing all these things right. You've dimmed the lights,
et cetera, et cetera. What else can we do in
order to optimize our sleep? Well, I always say behavioral tools first, then look to nutrition, then, if necessary,
look to supplementation, and then, if still necessary,
look to prescription drugs obviously prescribed by a
board certified physician. Well, we've talked a lot
about the behavioral tools for critical period three. We have not talked a lot about the supplementation-based tools. There are supplements that for most people will greatly improve their
ability to fall and stay asleep and the three main
supplements in that category or that kit of sleep supplements, and I've talked about these before, are magnesium threonate,
so T-H-R-E-O-N-A-T-E, apigenin, A-P-I-G-E-N-I-N, apigenin, and theanine, T-H-E-A-N-I-N-E, theanine. Now, some important things to point out about mag threonate, as it's
called, apigenin, and theanine. First of all, you don't necessarily
need to take all three, although, many people
get a synergistic effect from taking all three. In fact, you may not even
need to take even one. What I recommend is that
if you're already doing all the behavioral tools regularly and you're still having
trouble falling asleep and staying asleep, well, then you might try
one of the supplements within this sleep stack. They do have fairly
wide margins for safety. Although, I should also say, anytime you're going to
add or remove something from your supplement protocol
or your nutritional program, you definitely want to
talk to your physician. I don't just say that to protect us. I say that to protect you. But for most people, the margins
of safety on these things are going to be pretty broad. A couple of notes about dosages. For some people, the dosages
of any one or several of the supplements I
mentioned will be zero. That is, you won't need them in order to get and stay asleep
most nights of your life. That's terrific if you don't need them. For many people, however, taking 145 milligrams
of magnesium threonate can be very beneficial. That's the dosage that most
people will benefit from. Some people need to go a little higher. Some people need to go a little bit lower. One of the reasons that
we've been pointing people towards single-ingredient
formulations these days is because it allows people to adjust the dosage of one component of a so-called sleep stack without having to disrupt the
dosage of another component, and so on. It also allows people to try just one element within the sleep stack without having to purchase
and try the others, which is a problem if
you're buying a blend of a lot of different ingredients. So 145 milligrams of magnesium threonate. 50, 5-0, milligrams of apigenin. And again, you could just
take the apigenin on its own. And 100 to 400 milligrams of theanine taken, again, alone or in combination with the other supplements
mentioned in the stack many people find allows
them to get really drowsy and fall asleep, sleep really deeply, and they feel much more
refreshed the next day and they don't have a grogginess to them. Now, a couple of notes about
these different supplements. About 5% of people report that magnesium threonate
really disrupts their gut. It gives them diarrhea
or gastric distress. In which case, don't take it. If magnesium threonate disrupts
your gut or your digestion to a point where it's
uncomfortable or at all and you don't like it,
don't take any of it. The proper dosage for you, in other words, would be zero milligrams. Now, in a slightly different way, many people who can
tolerate magnesium threonate or really thrive on magnesium threonate and like apigenin might find that theanine, even at the lowest dose
of a hundred milligrams, 'cause, again, the range is
a hundred to 400 milligrams, that theanine gives them such vivid dreams that they actually find it disruptive where they wake up in
the middle of the night or they find that the
sleep that they're getting is kind of anxiety ridden because of the intensity of those dreams. So some people might
choose to leave theanine out of the sleep stack and just take magnesium
threonate or apigenin And again, some people might
leave magnesium threonate out of the sleep stack. Again, all of this is really about finding the supplementation protocol
that's ideal for you. I should mention that whether or not you're taking one or two
or three of the components of the sleep stack, the ideal time to take those is 30 to 60 minutes before bedtime, especially if you haven't
had anything to eat for the three hours or so before bedtime. I confess that oftentimes I'll have a little bit of a
snack late in the evening, some berries or something. I try not to eat too close to bedtime, but some evenings just
because of work schedule, I'll get home late, be 9:00 p.m., and I'll eat a big meal and then I'll take the
sleep stack and fall asleep. Every once in a while,
that just so happens. Nobody's perfect. Certainly I'm not. But that sleep stack
can be very beneficial. And I do think that it's
preferable to melatonin. Here's the reason. First of all, melatonin is a hormone that you endogenously make. You now know a lot about melatonin and it's controlled by light, meaning light inhibits
it or eliminates it, darkness promotes it. And melatonin indeed
can help us fall asleep, but the dosages of melatonin that are contained in
most commercial products is far, far, far greater than what we would make endogenously. So it's really supraphysiological. So that's of concern because melatonin is not just responsible for making us sleepy and fall asleep. It also does things like interacts with other hormone systems, testosterone and estrogen, even in the puberty system, in kids. Is taking melatonin every
once in a while a problem for adjusting to jet lag, et cetera? Probably not. I would even say no. But taking it chronically over time, especially kids taking
it chronically over time, can potentially be problematic. So at least in my opinion,
these other supplements are going to be preferable to melatonin. Now, as I mentioned in the
beginning of today's episode, there are some other things that I certainly take
every once in a while and that other people
might consider taking in addition to the sleep
stack I talked about before or in place of that sleep stack if that sleep stack
doesn't work well for them. So every third or fourth night, I will take two grams of glycine and a hundred milligrams of GABA in addition to the standard sleep stack that I talked about before. So I'm taking mag threonate,
apigenin, and theanine, and then I will also take two
grams of glycine and GABA, which I find greatly enhances
my ability to get into sleep. But the reason I only add glycine and GABA every third or fourth night is that if I take it too often, I find that the entire sleep stack doesn't work quite as effectively. I don't know exactly why this is the case, but in any event, that's what I do. And more recently, I've
also started using inositol, in particular myo-inositol. Every other night, I'll take
900 milligrams of myo-inositol in addition to mag threonate,
apigenin, and theanine, and not on the nights when
I take glycine and GABA. So I'm adding 900 milligrams of inositol to the standard sleep stack of mag threonate, theanine, and apigenin. And what I find is not only
does it greatly enhance my ability to fall asleep quickly, but if I wake up in the
middle of the night, which I often do to use the bathroom, I find it very, very
easy to fall back asleep. Whereas when I don't take
inositol every other night or so, I find that if I wake up
in the middle of the night, it's a bit more of a
challenge to fall back asleep. So inositol has a number of different uses that have been discussed
in terms of mental health and in terms of adjusting
anxiety for its daytime use. What I'm talking about is taking 900 milligrams of myo-inositol also 30 to 60 minutes before sleep along with the standard sleep stack and I found that to be
immensely beneficial. I also noticed that it
has a pretty long tail of anxiety suppression throughout the day. And I'm not somebody who
suffers from anxiety, but I have to say it just has led me to feel a bit calmer throughout the day, and I don't really know how to say this except in subjective terms, to feel a bit more buffered against or resilient against stress events. And if you look at the
literature on inositol and its interactions with the serotonin
system and other systems, that all makes sense as to
why that would be the case. So we'll provide links to
our so-called sleep kit, which is part of our
Neural Network Newsletter. It's a zero-cost newsletter where you can access this
information about supplements and other behavioral tools
for sleep in list form. But that sleep kit doesn't include some of the newer information that I've provided this episode, in particular, the
information about inositol and what I'm finding to be the very beneficial use of inositol for the ability to fall back asleep after waking up in the
middle of the night, which is something that a
lot of people struggle with. Now, that's supplementation
for falling and staying asleep, but we can return to the behavioral tools also as powerful levers and tools for falling asleep and
getting back to sleep. And again, we look to
NSDR, non-sleep deep rest, or the Reveri app as a way to do that. As I mentioned earlier, the Reveri app has been
developed on the basis of really high-quality,
peer-reviewed research, both clinical and non-clinical, by my colleague, David Spiegel, who's our associate chair
of psychiatry at Stanford. It's a wonderful tool. It does carry a cost after
the initial seven-day trial. I can tell you what the cost on that is so you can get a sense because I do realize that
anything that carries a cost, for some people, it won't be accessible. Right now, Reveri, and I should just mention, they didn't pay us for an ad read. I'm just telling you what they told me so that I can accurately report
what it costs to use Reveri. They have a monthly subscription to use the Reveri app at 14.99. You do get the seven-day free trial. They have a yearly subscription of 99.99 with a seven-day free trial. And they have a lifetime
purchase, one-time purchase, of 249 with no trial. It right now is only available
for Apple, not for Android, but they are, yes, going
to have it available for Android soon. There's a signup list there. I should mention that while
the cost might seem high, if you compare that cost
to, say, supplements, or you compare that cost to a
poor night's sleep over time, the cost, at least to me,
seems somewhat modest, certainly within range
for a number of people. But I acknowledge not within
range for other people, which is why I also want
to point to zero-cost tools and the zero-cost tool for
getting asleep, staying asleep, and falling back asleep is going to be NSDR. We'll put a link to a
non-sleep deep rest protocol that's available on YouTube, so available to anybody zero cost provided you have a internet connection. Again, dim the screen if you're going to turn
that on late at night. And there are a number of
other yoga nidra scripts and apps and sources around the internet, in particular, on YouTube, that are zero cost that you could use if the Reveri app is
outside your price range or is not preferable to you, et cetera. When I wake up in the middle of the night, it's usually to use the restroom. I'll go use the restroom. I'll keep the lights as dim as possible. I'll get back into bed. And if I find that it's
easy to fall asleep, great, I'm asleep. And if not, then I will
generally plug in the Reveri app. They have a fall back asleep hypnosis, and 99 times out of a hundred, I'm back asleep within minutes and I don't wake up until morning. Now, very briefly, I just
want to touch on some tools that are very commonly used
by many people out there, and believe it or not, there is peer-reviewed science
on things like eye masks. Do eye masks improve your
ability to stay asleep? And indeed, they do, provided they are not too tight and provided that the room is cool enough. Why? Well, eye masks cover the
upper half of your face, which is where glabrous skin is localized. Remember, palms of the
hands, bottoms of the feet, glabrous skin on the face. So a lot of people who
wear eye masks will wake up because they're too warm
if the room is too warm. So if you're going to use an
eye mask to keep light out, definitely make sure the room and your sleeping environment
and your bed are cool enough in order for you to stay asleep. In addition, I get a lot of
questions about earplugs. Here's the deal with earplugs. Some people find that
earplugs are very beneficial because, of course, they
prevent the entrance of sound into the ear that could wake us up. But some people find that the sound of their own beating of their
own heart can be disruptive and they get a sort of
humming in their head when they have those earplugs in. I'm one such person. Although, I have family members that like using earplugs when they sleep. So it's really up to you. You have to see whether
or not those earplugs help or disrupt your sleep. For me, they're no good. For some people, they really enjoy them. I don't use an eye mask unless I'm sleeping in a
really bright environment or I need to sleep on a plane
and things of that sort. Other tools that I'll just mention that have peer-reviewed
research to support them. Elevating your feet either with a pillow or by elevating the end of your bed by about three to five degrees can be really beneficial for
increasing the depth of sleep because of the so-called
glymphatic washout. This is the movement of
and circulation of fluids in your brain at night that lead to more wakefulness and actually can improve
cognitive function and a number of other things
related to brain health. There's one caveat to that. For people that suffer from acid reflux, having your ankles
elevated above your chest or above your heart in
the middle of the night can actually exacerbate that acid reflux. You want to do the opposite. You want to actually elevate
the head side of your bed by about three to five degrees. Now, one of the common
causes of sleep disruption that has tremendously detrimental effects is so-called sleep apnea. So this is basically bouts of suffocation or lack of oxygenation during sleep. This is particularly the case for people that are very heavyset, and that heavyset could be from obesity, it could also be heavyset
from having too much muscle. A lot of people who are
carrying too much muscle will actually have sleep
apnea without realizing it. Sleep apnea is actually very dangerous. It's associated with a number
of cardiovascular issues. It's associated with sexual dysfunction. It's associated with
issues with cognition. Sleep apnea is bad. A lot of people will have to use the PAP, which is a, it's a device. It looks like a sort of like
a snorkel mask or a dive mask. It's a whole apparatus that
people will go to sleep with. However, many people can relieve
themselves of sleep apnea provided it's not too serious and can sleep much better, in fact, I think all people
can sleep much better, if they train themselves to be nose breathers while they sleep. There are a lot of reasons
to be a nose breather unless you are breathing
very hard due to exercise or talking or eating. That was all covered
in James Nestor's book, "Breath: The New Science of a Lost Art." It's been covered in a
number of different podcasts. We've talked about it
on this podcast as well. It's a good idea to be a nose breather unless you need to mouth breathe. And it's a great idea, it's a superb idea, to be a nose breather in sleep. And one way to really get good at that is to take a little bit of medical tape and to tape your mouth
shut before going to sleep. You heard me right. Put some medical tape over your mouth and force yourself to
nose breathe during sleep. It also prevents snoring in most cases. Really offsets sleep apnea. Sleep apnea, again, being a
very serious health concern. I should also mention as a tool that if you have a hard time
being a nose breather in sleep, you can try doing your
cardiovascular exercise, at least the lower-intensity
cardiovascular exercise, through purely nasal breathing. And one way to do that, again,
is to tape your mouth shut or put a gulp of water in your mouth, but don't actually swallow
that mouth full of water, or to use a mouthpiece or just deliberately
keep your mouth closed and insist on breathing through your nose. Most people find that when they start doing
cardiovascular exercise that way, it's really challenging at first, but over time, they
actually can feel quite calm and still can generate
a lot of physical effort purely using nose breathing. The reason that doing nose breathing during cardiovascular exercise translates to being a
nose breather during sleep is that your sinuses actually
can dilate, they're plastic, and over time, plastic meaning they're malleable that is, and they can become wider. You're not going to get giant
nostrils. Don't worry about it. Your airways within your skull, 'cause that's what the sinuses really are, these little passages within the skull, and, of course, within the nasal passages, will dilate and will allow you to breathe more easily through your nose. But for those of you that are waking up in
the middle of the night breathing on your back [breathing heavily] or your partner is telling you that or other people are telling you that or you're that person on the plane with your mouth hanging open and drooling and your mouth breathing, terrible, terrible,
terrible for health reasons and other reasons, put some a medical tape over your mouth, learn to be a nose breather during sleep. Your sleep will improve and your daytime feelings of wakefulness and focus will improve, your cardiovascular health will improve, and on and on and on. So now we've largely covered
the tools that one could use to get and stay asleep, and we talked about exercise, we talked about temperature, we talked about supplements, and we talked about, of course, keeping the sleeping environment both cool and as dark as possible. I do want to mention a
couple of broad contour tools that will impact your ability to sleep really well on a consistent basis and the one that impacts
the most number of people is weekends. Turns out that most
everybody feels the impulse to sleep in on the weekend, especially if they've been
out late the night before. However, the data show that keeping relatively
consistent sleep and wake times is really going to enhance the quality and depth of your sleep. So if you stay out late one night, sure, you might allow yourself to sleep in an extra hour or so, but you should really try
to avoid sleeping in longer than an hour beyond your
normal wake-up time. That's right. If you normally get eight hours of sleep and you wake up at 7:00 a.m., probably okay to wake up
at 8:00 a.m. on the weekend or after a night out the night before, but try not to sleep until 11 or noon thinking that you're going
to catch up on your sleep or that's better than waking
up at a consistent time. It would be better to wake
up at a consistent time plus or minus an hour and get a nap in the afternoon provided that nap, again, isn't too long. And the other tool that relates to nights that
you stayed out too late or that you feel like you
want to sleep in a bit more in the morning is if you are going to wake
up at your consistent time. So for example, normally
you go to bed at 10 and you wake up at six. Let's say that's your schedule. And you end up staying up late one night until midnight or one for whatever reason and the next morning you wake up at seven and you're still groggy. In that case, you absolutely want to wait to ingest caffeine 90 to
120 minutes after waking. You really do because there are good data to support the fact that
caffeine can disrupt sleep. Yes, that's obvious. Caffeine especially disrupts sleep if you take it too late in the day. That's very obvious as to
why that would be the case. But caffeine especially disrupts what's called compensatory sleep. So if you start changing your waking time and your to sleep time and you start using additional caffeine to offset the sleepiness
that you're experiencing because of those late nights out, well, that's when you
really start to disrupt not just your nighttime sleep, but your daytime compensatory
sleep, so those naps. You also are disrupting the
total architecture of sleep in the early morning hours. There's a lot of great science
that's been put to this, or that's emerged from this, I should say. So try and keep those sleep-wake
times relatively constant plus or minus an hour, and try as much as you can
to delay that caffeine intake 90 to 120 minutes after waking every day, but especially on days where you wake up and you feel you haven't
gotten enough sleep. In that case, I highly recommend you just use NSDR or the Reveri app or some other form of deep relaxation to try and compensate
for the lack of sleep, knowing, of course, that
there's no complete compensation for lack of sleep. There are just things that we can do to partially offset lack of sleep. Now, a couple of final
points and additional tools that I think are going to
be useful to everybody, in particular, people
who have young children or are following a shift work schedule or who are experiencing jet lag. Keep in mind, jet lag
can be due to travel, which is obvious, but jet lag can also be due to getting woken up in the
middle of the night, right? Your body doesn't know the difference between flying to a new time zone and getting woken up in
the middle of the night. The tool that I'd like to offer you is an understanding of something
called temperature minimum. And I'm going to make
this as simple as possible and I'm confident that
everyone can understand this even if you don't have
any science background. Here's the question you
need to ask yourself. What is your typical wake-up time, okay? What's your typical wake-up time? If for you, your typical
wake-up time is 7:00 a.m. plus or minus half an hour, and that could be 7:00 a.m. because you set an alarm clock or it could be 7:00 a.m. because you naturally wake up
at 7:00 a.m., doesn't matter, if your typical wake-up
time most days is 7:00 a.m., well, then your temperature
minimum is 5:00 a.m. That's right, your temperature
minimum is not a temperature. It's a time within your 24-hour cycle. Approximately two hours before
your typical wake-up time, your body is at its lowest temperature that it will ever be in the 24-hour cycle. That's why it's called
your temperature minimum. Here's what you need to know
about your temperature minimum. If you view bright light,
exercise, or drink caffeine or all of the above in the two to four hours before
your temperature minimum, that will delay your clock. What that means when
I say delay your clock is it will make you want
to go to sleep later and wake up later the next night, okay? So let's run this exercise for you, the person waking up at 7:00
a.m. on a regular basis, I can predict with almost certainty that your body is going to
be at its lowest temperature at 5:00 a.m.. So what that means is that if you get up at
3:00 a.m. or at 4:00 a.m. and you flip on bright
lights in your house or in your bathroom or you have a cup of coffee or you do any kind of exercise or you get up and head to the airport, the mechanisms in your brain and body that control timing of sleep and timing of waking will shift. They will delay. It's as if you put your clock
on hold for a little while and then let it start again, okay? That's the simplest way I can describe it. And you will tend to
want to go to sleep later and wake up later the following night. Now, the opposite is true if you view bright light, drink caffeine, or exercise or socialize, I should say, in the hours immediately after
your temperature minimum. So for you in this example, the person who's waking up at 7:00 a.m., your temperature minimum is 5:00 a.m., if you view bright light, exercise, maybe have a snack, maybe
not, or socialize, move about, at 5:30 or 6:00 a.m. or 7:00 a.m. That will tend to phase
advance your clock. It will tend to basically make you want to go to bed earlier
and wake up earlier the following night. Now, I used this example of a person who wakes up
typically at 7:00 a.m. whose temperature minimum is 5:00 a.m., but, of course, you need
to adjust that for yourself if you're somebody who
wakes up at 9:00 a.m. or at 5:00 a.m. et cetera. Why do I offer this as a tool? Well, this is an immensely powerful tool if, for instance, you
are headed to a time zone where you need to go to bed earlier and wake up earlier once you
arrive in that time zone. What it means is in the day
or two before you leave, you can force yourself to
exercise, drink caffeine, maybe even to eat a meal
early in the morning, or maybe you still fast
early in the morning and that's really up to you, but you force yourself
to do the activities that are going to phase
advance your clock. Whereas if you're traveling to a time zone where you are going to need
to go to sleep much later and you're going to need
to wake up much later or even a little bit later, you can do those things in the hours prior to
your temperature minimum. Now, for those of you
that work shift work, this can be especially useful, but I want to say a couple
of things about shift work. There are a lot of details
about shift work and jet lag in an episode that I did specifically about jet lag and shift work. So for the deep dive, go there, but suffice to say this for now, if you are going to do shift work, try to stay on the same shift
for two weeks at a time. It's very detrimental to brain and body, it can even be horrifically challenging for your brain and body
in a number of ways, if you are switching on
the so-called swing shift, you know, you're working
three days the night shift, three days the day shift, three days the night
shift, three days the... Try and stay on the same
schedule as much as possible. And I should say for everybody, people who are jet lagged and
engaged in shift work or not, but just for everybody, if you need to be awake in
the middle of your sleep cycle and it's not just a quick
departure to the bathroom and back to bed, but you really need to be awake, you know, you're feeding a baby or you're taking care of a loved one or you need to do
something that's critical or you need to work, if possible, use red light, okay? Now, for shift workers
who really are trying to stay awake all night and sleep all day, this is not going to be ideal, but for people that, for instance, need to stay up really late one night or wake up especially
early, like 3:00 a.m., to prepare for an exam that
you're just not ready for or to head to the airport, et cetera, using red light has been shown to allow people to be awake enough and obviously see what they need to see in order to perform
their activities safely but it does not seem to
disrupt the cortisol rhythm that is the healthy,
normal cortisol rhythm. Now, I realize this is
kind of an advanced tool and many people won't have access to this. There are a number of different
sources for red lights now. Companies like Joovv or KOZE light. These are different brands. I don't have any affiliation to any of these brands, I should say. There are a number of different red light bulb sources out
there and commercial sources that you can explore if you want. But understanding this temperature minimum is really powerful because it allows you
to adjust your schedule depending on travel, depending on changing work
schedules or school schedules. And if you're not a morning person, you can use the tools related
to temperature minimum to really become a
morning person over time, and it actually is pretty easy. And I talked about this
in a previous episode but I'll just mention
that there have been shown to be important, positive
effects on cognition, on even grip strength
and physical performance, for people that are early morning risers, and that's especially true for night owls that deliberately shift
themselves to become early risers. Okay, so that's a lot of
information and a lot of tools and I suppose the one set of tools that I really didn't
drill into too deeply, the ones related to
jet lag and shift work. And again, please check out the episode on jet lag and shift work
if that's relevant to you. But I think for most people
who are going to sleep at night and are trying their best
to sleep well at night and are trying their best to wake up in the morning at whatever hour and stay alert and focused
throughout the day, maybe with a brief nap, the tools that I talked about today related to light,
temperature, food, exercise, caffeine, supplements, and digital tools, I'm hoping will prove to
be very useful for you. They certainly are all supported by excellent peer-reviewed research. And I should just emphasize again that most of the tools we talked about are completely zero cost. So while the supplements and
some of the digital tools do carry some cost to them, I really want to encourage everybody to get your behaviors right. Get all of the things related
to your timing of exercise and type of exercise in the best possible
order and time of day. We talked about this critical
period early in the day and then another critical
period in the middle of the day and the late afternoon and then this third critical period in the middle of the night. Different tools for the
different three critical periods. I promise that if you
start to implement some, or ideally, all of these tools, the quality of your sleep
will increase tremendously. And of course, in doing so, the quality of your daytime alertness and your ability to focus
will improve tremendously. Again, sleep is the absolute foundation of your mental health,
your physical health, and your performance in all endeavors. So if there's one area of your life to really focus on and try and optimize, if your goal is to be
happier and more productive and just to have a better life overall, I can confidently say that sleep is really
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