“Office Hours” — In this episode, I answer your most commonly asked
questions about science-supported tools for accessing more alertness,
better learning, and quality sleep. I also cover when to exercise,
time meals, and how to systematically vary your temperature to achieve
specific effects on your nervous system.
[upbeat music] -- Welcome to the Huberman Lab Podcast where we
discuss science and science-based tools for everyday life. I'm Andrew
Huberman, and I'm a Professor of Neurobiology and Ophthalmology at
Stanford School of Medicine. 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. Along those lines, I want
to thank the sponsors of today's podcast. Our first sponsor is
Athletic Greens, which is an all-in-one vitamin mineral probiotic
liquid supplement. I've been using Athletic Greens since 2012 because
I really like getting my total vitamin mineral base covered in one
easy to consume product. It also tastes really good. I mix mine with a
little bit of lemon juice. I've been doing that well over a decade
now. And the inclusion of probiotics is important to me because
there's a lot of data out there right now about the importance of gut
health for the immune system for, mood. And so by combining all these
things in one product you get all those things at once. If you want to
try Athletic Greens, you can go to athleticgreens.com/huberman and
that will give you a special offer where you will get a year supply of
liquid vitamin D3 and K2 vitamin D3 has been shown to be important for
various aspects of immune function as well as other biological
functions. And so once more, if you want to try athletic greens and
get the year supply of vitamin D3 K2 just go to
athletigreens.com/huberman. The other sponsor of today's podcast is
InsideTracker. InsideTracker is a way to measure metabolic factors,
hormones, and DNA related factors by way of blood tests and saliva in
order to assess one's health. I'm a big believer in blood tests and
saliva tests for assessing one's health markers, because I like data.
And there's really no other way to measure what's going on in one's
body without taking the occasional blood test or saliva test. You can
guess what's going on but if you really want to know what's going on
under the hood InsideTracker can be of great help. One of the problems
with a lot of products out there or just regular blood testing is that
you get a lot of data back about the levels of various hormones,
metabolic factors, et cetera, but you don't know what to do with those
data. Great thing about InsideTracker is provided in a format. They
have an online dashboard that given your particular levels of various
things directs you toward potential lifestyle related changes like
changes in exercise, or changes in sleep patterns, or changes in
nutritional patterns, that can really help move those markers and
those numbers on those metabolic factors, hormones, et cetera in the
direction that you want. If you'd like to try InsideTracker you can go
to insidetracker.com/huberman. And if you do that, you'll 25% off
their program at checkout. Okay, let's get started. Today is episode
three of the podcast and it is office hours. Office hours as many of
you know, it's where students come to the office of the professor, sit
down and ask questions, requesting clarification about things that
were confusing, or to simply go down the route of exploring a topic
with more depth and detail. I asked for your questions to be listed in
the comment section of the previous two episodes of the podcast on
YouTube, as well as on Instagram. And I first of all just want to
thank you for the many questions, they are excellent. We read them
all. We distilled from that large batch of questions to two types of
questions. Questions that were asked very often and were light very
often with a little thumbs up like tab as well as questions that we
thought could really expand on the topics that we've covered
previously. And today we're going to cover both of those. If we did
not get to your question, please don't despair. We will keep track of
those. And we have several more episodes devoted to this topic of
sleep and wakefulness and learning during the month of January, maybe
even, leaking over a little bit into the month of February. So, we
have time that's one of the unique formats of this podcast is that we
have time for dialogue, we have time for your questions and we have
time to really go deep into these topics. It's official Costello is
sleeping in the background. So if you hear snoring, Costello is going
to be keeping time with his deep and melodic snoring. There he goes.
So the questions that we received, I batched crudely into a couple of
different categories, light, exercise, supplementation, temperature,
learning, plasticity, and mood, and sort of mood related disorders.
There were a lot of questions about those. Before we begin any of this
I want to point out something that I, I always say it sounds like
boiler plate but it's important not just to protect me but to protect
you, which is that I am not a physician. I'm not a medical doctor. I
don't prescribe anything, including behavioral protocols. I'm a
professor. So I profess a lot of things based on quality peer reviewed
studies. You should take that information. You should filter it
through whatever it is that you currently happen to be dealing with,
whether or not that's health or illness, you should consult with a
licensed healthcare professional before you add or remove anything
from your daily life protocol. I'm not responsible for your health.
You are, so be smart with this information and be a stringent filter,
as we say. Okay, very well let's get started on the actual material.
Somebody asked, what is the role of moonlight and fire, I'm presuming
they mean fireplace or candle or things of that sort, in circadian
rhythms.
Is it okay to view moonlight at night or will that wake me up? Will a
fire in my fireplace or using candle light be too much light. Great
question, also offers me the opportunity to share with you what I
think is a quite beautiful definition of what light is in a
quantitative sense. So I've mentioned a few times the use of apps and
light meters and things to measure things like locks, which sometimes
are also described in terms of Kendals. So those are the two units for
measuring light intensity. Typically lux, L-U-X is the, is the unit.
And so before we go forward and discuss this many lux or that many
lux, I want to just tell you what a lux is because it relates to this
question. One lux equals the illumination of one square meter surface
at one meter away from a single candle. Think about that. So somebody
actually decided at some point that the amount of illumination at one
square meter surface, one meter away from a single candle, that equals
one lux. So when we talk about 6,000 lux of light intensity or 10,000
lux of light intensity, now you have a kind of a reference or a
framework that would be the equivalent of, you could think of it as
6,000 candles all with their light intensity shown on one square meter
from one meters distance away. Or of course, if it was a different
number of lux it would be a different number of candles. So you get
the idea. Here's the great thing. It turns out that moonlight, candle
light, and even a fireplace, if you have one of these roaring fires
going in the fireplace, do not reset your circadian clock at night and
trick your brain into thinking that it's morning even though if you've
ever sat close to a fireplace or even a candle, that light seems very
bright. And there are two reasons for that that are very important.
The first one is that these neurons in your eye that I discussed in
the previous episode these melanopsin ganglion cells also called
intrinsically photosensitive ganglion cells. Those cells adjust their
sensitivity across the day, and those cells respond best to the blue-
yellow contrast present in the rising and setting sun, so-called low
solar angle sun, also discussed in the previous episode, but those
cells adjust their sensitivity such that they will not activate the
triggers in the brain that conveyed daytime signals when they view
moonlight, even a full moon a really bright moon or fire. Now this
does raise an interesting kind of thought point, which is, you know, a
lot of people talked about lunacy and the fact that when there's a
full moon out people act differently and behave differently. There's a
lot of lore around that. There's actually a little bit of quality
science around that that maybe we can address in the future. But,
moonlight is typically not going to wake us up too much, except maybe
the moon is really full and really bright, there's possibility for
that. So, providing you're not going to burn down the structure you're
in, you're not going to burn down the forest, enjoy your, your
fireplaces, enjoy your lights from candles. And those are perfectly
safe without disrupting your circadian rhythm. Because we talked about
just how crucial it is to avoid bright lights between the hours of
about 10:00 PM and 4:00 AM. Except when you need to view things for
sake of safety or work or so and so forth. I also received a lot of
questions about red light.
Now, I think I was asked those questions because red light is used in
a number of different commercial products where these products tend to
include a sheet, of very bright red lights. That one is supposed to
view early in the day. And there are various claims attached to these
red light devices that they improve mitochondrial function, that they
improve metabolism there- I'm going to be really honest and I can't
name brands, and I'm not going to name particular studies. 'Cause what
I'm about to say about these studies is not particularly unkind but
let's just say that none of the studies that I've seen except for one
that I'll talk about in a moment, pointing to the positive effects of
red light on the visual system are published in blue ribbon journals.
They tend to be published in journals that I had to work hard to find.
I'm not sure what the peer review and stringency level is. Now, that's
not to say red light isn't beneficial because there is one study in
particular that came from Glen Jeffrey's Lab at the University of
College, London it was published last year. Glen is somebody I happen
to know is an excellent reputation, excellent vision scientist, what
this study essentially showed. And again, this is a study that I very
much liked the data and think it was done with very high standards.
What this study shows is that, viewing red light for a few minutes
each morning can have positive effects on mitochondria in a particular
retinal cell type, that tends to degenerate or decline in function
with age in humans. And that cell type is the photoreceptor. The
photoreceptor is a type of cell in your eye that sits at the back of
the eye. It's kind of some distance away from the ganglion cells. And
it's the cell that converts light information into electrical signals
that the rest of the retina and brain can understand. These are
vitally important cells without them, people are blind. And many
people's vision gets worse with age. In particular, age related
macular degeneration but also related to some other factors including
photo receptor functionality just getting worse with time. And what
Glen showed was that red light flashes delivered in particular early
in the day but not late in the day can help repair the mitochondria.
Now this study needs more support from additional studies of course.
They are doing a clinical trial. They did report on what I think it
was 12 patients. And so the work is ongoing, but that was very
interesting. And it points to some potentially really useful things
about red light. However, most of the questions I got about red light
for sake of office hours were about the use of red light later in the
day. So here's the deal, in principle red light will not stimulate the
melanopsin retinal neurons that wake up the brain and circadian clock
and signal daytime. However, most of the red lights in particular the
red lights that come on these sheets of these products that people are
supposed to view them in order to access a number of proclaimed health
effects, those are way too bright and would definitely wake up your
body and brain. So if you're going to use those products and I'm not
suggesting you do, or you don't, but if that's your thing, you would
want to use those early in the day. Who knows you might even derive
some benefit on mitochondria function in these photo receptors. But if
you're thinking about red light for sake of avoiding the negative
effects of light later in the day and at night, then you want that red
light to be very, very dim, certainly much dimmer than is on most of
those commercial products. Now, do you need red lights? No. Although
red lights are rather convenient because you can see pretty well with
them on, but if they're dim, they won't wake up the circadian clock.
They won't have this dopamine disrupting thing that we talked about in
the previous podcast. So there's a role for red light potentially
early in the day and for mitochondrial repair in the photoreceptors,
there's a role for dim red light later in the day and at night. So
you're starting to notice a theme here which is that, there's no
immediate prescription of look at these light, it's look at these
lights potentially if that's what you want to do at particular times
of day and we're particular intensities. It brings us back to the blue
light issue which is so many people are obsessed with avoiding blue
light, but you actually want a ton of blue light early in the day and
throughout the day. So don't wear your blue blockers then or maybe
even don't wear them at all. And at night, it doesn't matter if you
have blue blockers on if the lights are bright enough, then you're
still going to be activating these cells and mechanisms. I just want
to add something about the science behind the blue blocker confusion.
So these melanopsin retinal cells do react to blue light. That that is
the best stimulus for one of these melanopsin cells, which led to the
belief that blue blockers would be a good thing for preventing
resetting of the circadian clock at night and deleterious effects of
screens, et cetera. However, the people that made these products fail
to actually read the papers from start to finish or if they did, they
didn't comprehend a critical element which is that most of those
papers early on took those neurons out and put them in a dish. And
when they did that, they divorced those neurons from their natural
connections in the eye. It turns out in your IMI right now, because
that's what we care about, these cells exist and the cells respond to
blue light but also to other wavelengths of light because they not
only respond directly to light as they do in a dish, they also respond
to input from photo receptors. So if you talk to anyone in the
circadian biology field, they'll tell you, "Oh, yeah this blue light
thing, has really gotten out of control." Because people assume that
blue light is the culprit because blue light is the best stimulus.
That doesn't mean that blue light is the only stimulus that will
trigger these cells, okay? So like many things a scientific paper can
be accurate without being exhaustive. And a lot of claims about
products can be accurate, but not exhaustive. So blue light during the
day is great. Get that screen light, get that sunlight especially
getting overhead lights. I'll talk about all this in the previous
podcast, but at night you really want to avoid those bright lights.
And it doesn't matter if it's blue light or something else. And so
there was a real confusion about the papers and the data when most of
those product recommendations were made. Okay. While we're on that
topic, let's talk about light in other orifices of the body.
I made a kind of a joke about this, the last podcast episode but a
couple of people wrote to me and said, well, I've seen some claims
that light delivered to the ears into the ears or the roof of the
mouth or up the nose can be beneficial for some setting circadian
rhythms, no. Not directly anyway. And this is a great opportunity for
us to distinguish between what is commonly called the placebo effect
but a more important way to think about any manipulation behavioral or
otherwise that you might do is the difference between modulation and
mediation. There are a lot of things that will modulate your biology.
Putting a couple of lights up your nose, please don't do this. Might
modulate your biology by way of the stress hormone that's released
when you stuffed those things up your nose. Remember earlier a
previous podcast, I said that virtually anything we'll face shifts
your circadian rhythm if it's different and dramatic enough. So the
question is, is it the light delivered up the nose or through the ears
or some other orifice that's mediating the process? Is it actually
tapping into the natural biology of the system that you're trying to
manipulate? And this is where I like to distinguish between real
biology and hacks. I don't like the word hack or frankly neuro hacking
or bio hacking. I just don't like the term because a hack is is using
something for a purpose for which it was not intended, right? But
where you can kind of, it's kind of a cheat and that's not how biology
works well. So I try and distinguish between things that really
mediate biological processes and things that Modulate them. There are
a number of commercial products out there with some studies attached
to them, claiming that light delivered to the ears or wherever can
adjust your wakefulness or adjust your sleep. I've looked at those
papers again, I'm probably going to lose some friends by saying this
but maybe I'll gain a few as well. Not blue ribbon journals, frankly,
oftentimes read the small print. There was a conflict of interest
clause there related to commercial interests. If somebody disagrees
with me outright on this and can send to me a peer reviewed paper,
published in a quality journal about light delivered anywhere, but the
eyes of humans that can mediate circadian, rhythms, wakefulness et
cetera, I'm more than happy to take a look at that and change my words
and stance on this and do it publicly, of course. But until then I'm
guessing that the proper controls were not done of adjusting for heat
that could be delivered which can definitely shift circadian rhythms.
We're going to talk about temperature and other things like that. So
light to the eyes folks is where these light effects work in humans,
in other animals, they have extra ocular photo reception in humans,
no. And just be mindful, I mean, I'm not trying to encourage people to
avoid certain products in particular but just be mindful of this
difference between modulation and mediation. A mediating, a process
through a hard wired or long-standing biological mechanism is really
where you're going to see the powerful effects over time. I also, as
you've probably noticed, I really tend to favor behavioral tools and
zero cost tools first, and getting those dialed in before you start,
plugging in and swallowing and putting things in various places just
to really figure out how your biology works and explore that, unless
there's of course a clinical need to take a prescribed drug in which
case, by all means, listen to your doctor. Okay, a huge number of
people asked me about what about light through windows?
And I actually did an Instagram post about this look, setting your
circadian clock with sunlight coming through a window is going to take
50 to 100 times longer. If you want the date on that, I'd be happy to
send you to the various papers that were described in the previous
podcast that Jamie Zeitzer from Stanford. And I have discussed also
elsewhere but here's really the key thing with us. Do the experiment.
You can download the free app Light Meter. You can have a bright day
outside or some sunlight hold up that app, take a picture. It'll tell
you how many lux now, you know what lux are. It will tell you how many
lux are in that environment. Now close the window. And if you want
close the screen or don't open the screen you can do all sorts of
experiments. You'll see that it will at least half the amount of lux.
And it doesn't scale linearly. Meaning let's say I get a 10,000 lux
outside, 5,000 looking out through an open window and then I closed
the window and it's 2,500 lux. It does not mean that you just need to
view that sunlight for twice as long if it's half as many lux, okay?
It's not like 2,500 lux means you need to look for 10 minutes and
5,000 lux means you look for five minutes. It doesn't scale that way
just because the biology doesn't work that way. Best thing to do is to
get outside, if you can, if you can't next best thing to do is to keep
that window open. It is perfectly fine to wear prescription lenses and
contacts. Why is it okay to wear prescription lenses and contacts,
when those are glass also, but looking through a window, diminishes
the effect. Well, we should think about this. The lenses that you wear
in front of your eyes by prescription or on your eyes are designed to
focus the light on to your neural retina. In fact, that's what near-
sightedness is, is when the image because your lens doesn't work quite
right. The image falls in front of the neural retina, wearing a
particular lens in front of that focuses the lens onto your retina
onto these very neurons. So they can communicate that to the brain.
It's Costello is loving this light. He's deep in sleep. And if we,
maybe we could play him some tones and he'll remember it later, based
on the studies, we're going to talk about in a little bit. I don't
know how we'd know if he remembered it or not, but prescription lenses
are fine. In fact, they're great for this reason they're actually
focusing the light onto the retina. So think about this logically and
all of a sudden it makes perfect sense your glass window or your
windshield or the side window of your car, it isn't optically perfect
to bring the image and the light onto your retina. In fact, what it's
doing is it's scattering and filtering light in particular the
wavelengths of light that you want. So, if you live in a low light
environment lots of questions about this. We talked about this, the
previous podcast but just get outside for longer or, and/or use really
bright lights inside.
Okay, so let's think about why I'm making some of these
recommendations because I think it can really empower you with the
ability to change your behavior in terms of light viewing and other
things, depending on time of year, depending on other lifestyle
factors. The important point to understand is that early in the day,
your central circadian clocks and all these mechanisms are looking for
a lot of light. I mean, they don't have a mind of their own, but it
needs a lot of light to trigger this daytime signal, alertness et
cetera. And early in the day, but not in the middle of the day, you
can sum or add photons. So there's this brief period of time early in
the day, when the sun is low in the sky when your brain and body are
expecting a morning wake up signal where let's say, it's not that
bright outside. Someone sent me a picture or a little movie of their
walk in England, and it was pretty overcast and they were using light
meter and they said it's only about 700 lux or maybe even less. And I
said, well, stay outside longer. But when you get inside, turn on the
lights really bright and overhead lights in particular, because those
will be best for stimulating these mechanisms. And that's because at
least for the first few hours of the day, you can continue to some or
add photon activation of the cells in the eye and the brain. In the
middle of the day, once the sun is overhead, or even if you stay
inside all morning, and then you're in the circadian dead zone, which
sounds terrible and it is terrible. You doesn't matter if you get a
ton of artificial light or even sunlight, you're not going to shift
your circadian clock. You're not going to get that wake up signal. And
then in the evening, you want to think about this whole system as
being vulnerable to even a few photons of light because of their
sensitivity to light really goes up at night. And I talked last time
about how you can protect against that sensitivity by looking at the
setting sun and watching the evening sun, even if it's not crossing
the horizon around the time of sunset. And that's because it adjusts
your retinal sensitivity and your melatonin pathway so that light is
not as detrimental to melatonin at night. Think about the afternoon
sunlight viewing as kind of a, I think of it as kind of a Netflix
inoculation. It allows me to watch a little bit of Netflix in the
evening, although it's very hard to watch a little bit of anything on
Netflix.
It seems like there's some other neuro-biological process that going
on there where I have to watch episode after episode after episode.
But in any case, you can protect yourself against some of that bad
effect of light at night by looking at light in the evening. It really
does adjust down the sensitivity of the system. Okay. I want to talk
about seasonal changes in all these things as they relate to mood and
metabolism. So depending on where you are in the world, Northern
hemisphere, Southern hemisphere at the equator or closer to the poles,
the days and nights are going to be different lengths. That just makes
sense. But that translates to real biological signals that impact
everything from wakefulness and sleep times but also mood and
metabolism. So here's how this works. Now, after seeing the previous
episode of the podcast and paying attention here, you are armed with
the knowledge to really understand how it is that believe it or not,
every cell in your body is tuned to the movement of the planet
relative to the sun.
So as all of you know, the earth spins once every 24 hours on its
axis. So part of that day were bathed in sunlight depending on where
we are the other half of the day or part of the day we're in darkness.
The earth also travels around the sun 365 days is the time that it
takes, one year, to travel around that sun. The earth is tilted. It's
not perfectly upright. So the earth is tilted on its axis. So
depending on where we are in that 365 day journey and depending on
where we are in terms of hemisphere, Northern hemisphere, Southern
hemisphere, some days of the year are longer than others. Some are
very short, some are very long. If you're at the, at the equator you
experience less variation in day length and therefore nightlife. And
if you're closer to the poles, you're going to experience some very
long days. And you're also going to experience some very short days
depending on which poll you're at and what time of year it is. The
simple way to put this as depending on time of year the days are
either getting shorter or getting longer. Now, every cell in your body
adjusts its biology according to day length, except your brain, body
and cells don't actually know anything about day length. It only knows
night length. And here's how it works. Light inhibits melatonin
powerfully.
If days are long and getting longer, that means melatonin is reduced.
The total amount of melatonin is less because light is more, therefore
melatonin is less. If days are getting shorter, light can't inhibit
melatonin as much, through the summing of photon mechanisms that we
talked about before, and that melatonin signal is getting longer. So
every cell in your body actually knows external day length and
therefore time of year by way of the duration of the melatonin signal.
And in general, it's fair to say that in diurnal animals, meaning
animals like us that tend to be awake during the daytime and not
nocturnal animals, which tend to be awake at night. The longer the
melatonin signal, the more depressed not necessarily clinically
depressed, although that can happen but the more depressed our systems
tend to be. Reproduction, metabolism, mood, turnover rates of skin
cells and hair cells all tend to be diminished compared to the spring
and summer months for some Northern hemisphere, spring and summer
months, or the times in which days are very long. And there's less
melatonin that tends to, in almost all animals, including humans, more
breeding, more hormone elevation of the hormones that stimulate
breeding reproduction and fertility metabolism is up, lipid metabolism
fat-burning is up, protein synthesis is up. These things tend to
correlate with the seasons. Now, some people are very, very strongly
tied to the seasons. They get depressed, clinically depressed in
winter and light therapies are very useful for those people. Some
people love the winter and they're happiest in winter and they feel
kind of depressed in summer. Although that is far more rare. That
doesn't mean depression cannot exist in the summer, but when we're
talking about seasonal depression that tends to be true. It's more
depression in winter. Now there's other things that correlate with
seasonality. Suicide rates tend to be highest in the spring not in the
winter, but that has to do with some of the more complicated and
unfortunately tragic aspects of suicide which is that oftentimes
people will commit suicide not at the very depths of their energy
levels, but as they're emerging from those depths of low energy. So
we'll talk about suicidality and mood disorders in a later podcast
season, meaning a month later. But for now, just understand that
everybody is going through these natural fluctuations depending on the
duration of the melatonin signal. Now this might lead you to say,
"Well, then I should just really get as much light as I can all the
time and reduce melatonin feel great all the time." Unfortunately,
doesn't work that way because melatonin also has important effects on
the immune system. It has important effects on transmitter systems in
the brain, et cetera. So everybody needs to figure out for themselves
how much light they need early in the day and how much light they need
to avoid late in the day, in order to optimize their mood and
metabolism. There is no one size fits all prescription because there's
a range of melatonin receptors, there are a range of everything from
metabolic types to genetic histories, family histories, et cetera.
There is no one size fits all prescription but by understanding that
light and extended day length inhibit melatonin and melatonin tends to
be associated with a more depressed or reduced functioning of these
kinds of activity driving and mood elevating signals, and
understanding that you have some control over melatonin by way of
light, including sunlight but also artificial light, and that should
empower you I believe, to make the adjustments that if you're feeling
low you might ask, how much light am I getting? What am I getting that
light? Because sleep is also important for restoring mood, right? So
you need sleep. You can't just, just crush melatonin across the board
and expect to feel good because then you're not going to fall asleep
and stay asleep. Melatonin, not incidentally comes from, is
synthesized from serotonin.
Serotonin is a neurotransmitter that is associated with feelings of
well-being provided to proper levels, but well-being of a particular
kind. Well-being associated with quiescence and calm and the feeling
that we have enough resources in our immediate kind of conditions. Is
the kind of thing that comes from a good meal or sitting down with
friends or holding a loved one, or conversing with somebody that you
really bond with. Serotonin does not stimulate action. It tends to
stimulate stillness. Very different than the neuromodulator dopamine
which is a reward feel good neuromodulator that stimulates action. And
actually dopamine is the cursor to epinephrin, to adrenaline which
actually puts us into action. There it's actually made from dopamine,
right? So, you can start to think how about light as a signal that is
very powerful for modulating things like sleep and wakefulness but
also serotonin levels, melatonin levels. And I talked about this
previously but I'll mention once more, that light in the middle of the
night reduces dopamine levels to the point where it can start causing
problems with learning and memory and mood. That's one powerful reason
to void bright light in the middle of the night. Okay. Seasonal
rhythms have a number of effects but humans are not purely seasonal
breeders. Unlike a lot of animals, we breed all year long. In fact,
there's a preponderance of September babies in my life, not actual
babies, because they're born in September which means that they were
conceived in December, without knowing the details we can fairly
assume that. And December, at least in the Northern hemisphere at days
tend to be shorter and nights tend to be longer. So clearly humans
aren't seasonal breeders but there are shifts in breeding and
fertility that exist in humans, but also much more strongly in other
animals. So seasonal effects vary. Some of you will experience very
strong seasonal effects others of you will not. I think everybody
should be taking care to get adequate sunlight and to avoid bright
light at night throughout the year if possible. Throughout this
podcast and in previous episodes, I've been mentioning
neuromodulators, things like serotonin and dopamine which tend to buy
a certain brain circuits and things in our body to happen in certain
brain circuits and things in our body not to happen. One of the ones
I've mentioned numerous times is epinephrin which is a neuromodulator
that tends to put us into action, make us want to move.
In fact, when it's released in high amounts in our brain and body, it
can lead to what we call stress or the feeling of being stressed.
Several people ask me, what's the difference between epinephrin and
adrenaline. Adrenaline is secreted from the adrenal glands which sit
right above our kidneys. Epinephrin is the exact same molecule except
that it's released within the brain. And so people use these phrases
or these words rather interchangeably, epi means near or on top of
sometimes and neph, neph Anytime you see nephron or ph it means
kidney. So it means near the kidney. So epinephrin actually means near
the kidney. So it was used originally to describe adrenaline, but
epinephrin and adrenaline are basically the same thing and they tend
to stimulate agitation and the desire to move. That's what that's
about. Which brings us to the topic of exercise. Got a lot of
questions about exercise. What forms of exercise are best for sleeping
well? When should I exercise et cetera. There's a lot of them
individual variability around this, but I can talk about what I know
from the science literature and what I happened to do myself.
There are basically two forms of exercise that we can talk about
although, of course I realize there are many different forms of
exercise. There's much more nuance to this, but we can talk about
cardiovascular exercise, where the idea is to repeat a movement over
and over and over continuously. So that'd be like running, biking,
rowing and cycling this kind of thing. Or there's a resistance
exercise where you're moving, lifting, presumably putting down also
things of progressively heavier and heavier weight that you couldn't
do continuously for 30 minutes. So cardiovascular exercise is
typically the more aerobic type exercise and resistance exercise of
course is the more anaerobic type exercise. And yes, there's variation
between the two. Most studies of exercise have looked at aerobic
exercise because that's basically the thing that you can get a rat or
a mouse to do. You know what's really weird about rats and mice, they
like to run on wheels so much, that someone actually did this study,
it was published in science they put a wheel, a running wheel in the
middle of a field and mice ran to that wheel and ran on the wheel.
They turns out that what they like is the passage of the visual image
of the bars in front of their face, which I find kind of remarkable
and troubling because it seems so like trivial, but anyway they love
aerobic exercise. And so most of the studies were done on these mice
that love running on wheels. Whereas so far as it's been challenging
to find conditions in which mice really liked to lift weights or we'll
do it in a laboratory. So any weight bearing exercise studies really
have to be done in humans. And since humans are what we're interested
in, there are some studies looking at these two things and when they
tend to work best. Now you will see some places aerobic exercise is
best done in the morning and weight training is best done in the
afternoon. I think there's far more individual variation than that. I
think there are however, a couple of windows that the exercise science
literature and the circadian literature points to as windows related
to body temperature in which performance, injury, in which performance
is optimized injury is reduced and so on. And those tend to be 30
minutes after waking. And that probably correlates with the inflection
in cortisol associated with waking whether or not you've gotten light
or not, three hours after waking, which probably correlates to the
rise in body temperature sometime right around waking. And the later
afternoon, usually 11 hours after waking which is when temperature
tends to peak. So some people like to exercise in the morning. Some
people like to exercise in the afternoon. It really depends. I think
for those of us with very busy schedules, it's advantageous to be able
to do your training whenever you have the opportunity to do it, unless
you can really control your schedule. And so I would never want these
recommendations to seem like recommendations, what I'm really
describing are some opportunities, 30 minutes after waking, three
hours after waking or 11 hours after waking has been shown at least in
some studies to optimize performance, reduce injury and that sort of
thing. But you really have to figure out what works for you. A note
about working out first thing in the morning. Last time we talked
about non-photo phase shifts. If you exercise first thing in the
morning, your body will start to develop an anticipatory circuit.
There's actually plasticity in these circadian circuits that will lead
you to want to wake up at the particular time that you exercised the
previous three or four days. So that can be a powerful tool but you
still want to get light exposure. Because it turns out that light and
exercise converged, so giving even bigger, wake up signal to the brain
and body. So you might want to think about that. Some people find if
they exercise late in the day they have trouble sleeping in general
intense exercise does that, whereas the kind of lower intensity
exercise doesn't. I found some interesting literature that talked
about sleep need and exercise. I found this fascinating that if one is
waking not feeling rested and recovered from and yet sleeping the same
amount that they typically have, it's quite possible that the
intensity of exercise in the proceeding two or three days is too high.
Whereas if one can't recover no matter how much sleep they get,
they're just sleepy all the time, I realized these things are
correlated that the volume of training might be too high. Now I'm not
an exercise scientist. We should probably get Andy Galpin or somebody
else on here, who's really an expert in this kind of stuff. I do
realize as soon as anyone talks about exercise or nutrition publicly,
they're basically opening themselves up to all sorts of challenges
because you can basically find support for almost any protocol in the
literature. What I've looked at was two journals in particular,
International Journal Chronobiology and journal Biological Rhythms.
Excuse me, to assess these parameters that I I've mentioned just just
a moment ago because the studies tended to be done in humans. They
were fairly recent and they came from groups that I recognized as well
as knowing that those journals are peer reviewed. Many of your
questions were about neural plasticity which is the brain and nervous
system's ability to change in response to experience.
There was a question that asked whether or not these really deep
biological mechanisms around wakefulness, time of waking sleep, et
cetera were subject to neuroplasticity and indeed they are. Some of
that plasticity is short-term and some of it is more long-term.
There's a really good analogy here which is, if you happen to eat on a
very tight schedule where every day say it 8:00 AM, noon and 7:00 PM
is when you eat your food not suggesting you do this but let's say you
were to do that for a couple of days. After a few days, you would
start to anticipate those meal times where no matter where you were in
the world, no matter what was going on in your life about five to 10
minutes before those meal times, you would start to feel hungry and
even a little agitated, which is your body's way of trying to get you
to forage for food. And that's because of some peptide signals that
come from the periphery from your body, things like hypocretin norexin
that signal to the hypothalamus and brainstem to make you active and
alert and look for food and feel hungry. So there's kind of an
anticipatory circuit, that's a chemical circuit, but eventually over
time, the neurons, the neural circuits that control hypocretin orexin
would get tuned to the neural circuits that are involved in eating and
maybe even smell and taste to create a kind of eating circuit that's
unique to your pattern, to your rhythms. The same thing is true for
these waking and exercise and other schedules, including all trade-in
schedules. If you wake up in the morning and start getting your
sunlight, you start exercising in the morning or you exercise in the
afternoon, pretty soon, your body will start to anticipate that and
start to secrete hormones and other signals that prepare your body for
the ensuing activity of waking up or going to sleep. So if you get
onto a pattern or a rhythm, even if that rhythm isn't down to the
minute, you'll find that there's plasticity in these circuits and it
becomes easier to wake up early. If that's your thing or exercise at a
particular day if that's your thing. That's the beauty of
neuroplasticity. A number of people ask, "What can I do to increase
plasticity?" And that really comes in two forms. There's plasticity
that we can access in sleep to improve rates of learning and depth of
learning from the previous day or so. And there's this an SDR non-
sleep deep breaths that can be done without sleeping, to improve rates
of learning and depth of retention, et cetera. So let's consider those
both and you can incorporate these protocols if you like. Again, these
are based on quality peer reviewed studies. First, let's talk about
learning in sleep. This is based on some work that I'll provide the
reference for that was published in the journal Science. Excellent
journal, Matt Walker also talks about some of these studies done by
others in his book "Why We Sleep". The studies just to remind you are
structured in he following way an individual is brought into a
laboratory, Lowe does a spatial memory task. So there tends to be a
screen with a bunch of different objects popping up on the screen in
different locations. So it might be a Bulldog's face that might be a
cat, and it might be an Apple than it might be a pen in different
locations. And that sounds trivial easy but with time you can imagine
it gets pretty tough to come back a day later and remember, if
something presented in a given location was something you've seen
before and whether or not it was presented in that location or a
different location. If you had enough objects and changed locations
enough, this can actually be quite difficult.
In this study, the subjects either just went through the experiment or
a particular odor was released into the room while they were learning
or a tone was played in the room while they were learning. And then
during the sleep of those subjects the following night and the
following night, so this was done repeatedly for several nights, the
same odor or tone was played while the subjects were sleeping. They
did this in different stages of sleep non-REM sleep and rapid eye
movement, sleep REM sleep. They did this with just the tone in sleep.
If the subjects had the odor but not the tone, they did it with
putting the tone, if they had had the odor while learning. So
basically all the controls, all the things you'd want to see done to
make sure that it wasn't some indirect effects, a modulatory effect.
Okay. And what they found was that providing the same stimulus, the
odor, if they smelled an odor or a tone if the subjects heard a tone
while learning if they just delivered that odor or tone while the
subject slept, rates of learning and retention of information was
significantly greater. This is pretty cool. What this means that you
can cue the subconscious brain, and the asleep brain to learn
particular things better and faster. So how might you implement this?
Well, you could play with this if you want. I don't see any real
challenge to this provided the odor and is a safe one and then doesn't
wake you up and the tone is a safe one, and doesn't wake you up. You
could do this by having a metronome, for instance, while I'm learning
something, playing in the background or particular music and then have
that very faintly while you sleep. So you could apply this if you like
and try this. There are a number of groups I think now that are trying
this using tactile stimulation. So slight vibration on the wrist
during learning and then the same vibration on the wrist during sleep.
It does not appear that the sensory modality, whether or not it's odor
or auditory tone or tactile stimulation, some as a sensory
stimulation, whether or not it matters. It's remarkable because it
really shows that sleep is an extension of the waking state. We've
known that for a long time but this really tethers those two in a very
meaningful and actionable way. So I think I'll report back to you as I
learned more about these studies, but that's what I know about them at
this point. As long as we're there we might as well talk about
dreaming 'cause I got so many questions about dreams. A couple of you,
we want to ask me what their dreams meant.
Look, I don't even know what my dreams mean half the time. I
occasionally will wake up from a dream and remember it. If you want to
remember your dreams better, if you're somebody who has challenges
remembering your dreams, you can set your alarms that you wake up in
the middle of this one of these 90 minute cycles which toward morning
tend to be occupied almost exclusively by REM sleep. Remember early in
the night, you have less REM sleep than later in the night. But you
want to get as much sleep as you can 'cause that's healthy. So I don't
know that you want to wake yourself up. Some people find that writing
down their thoughts immediately first thing in the morning allows them
to relater spontaneously remember their dream they had. There's some
literature on that. The meaning of dreams is a little bit
controversial. Some people believe they have strong meaning other
people believe that they can be just spontaneous firing of neurons
that were active in the waking state and don't have any meaning. There
are good data to show that when you learn spatial, new spatial
environments that there's a replay of those environments, so-called
place cells that fire in your brain only when you enter a particular
environment, that those are replayed in sleep in almost direct fashion
to the way that things were activated when you were learning that
spatial task. Dreams are fascinating, they're were paralyzed during
dreams which brings us to another question. Somebody asked about sleep
paralysis. We are paralyzed for much of our sleep, so-called atonia so
presumably so we don't act out our dreams.
Some people wake up and they're still paralyzed. I've actually had
this happen to me not very many times, but a few times. And then they
jolt themselves awake and it actually is quite terrifying. I can say
from personal experience to wake up be wide awake and you cannot move
your body at all. It's really quite frightening. There are a couple of
things that will increase the intrusion of atonia into the wakeful
state which is essentially means you're waking up but you can't, you
can't move. One is marijuana, THC, a I'm not a marijuana smoker. I'm
not a copper. I don't know the legality where you live. So I'm not
saying one thing or another about marijuana. I'm just, the fact that I
had that experience without marijuana means that it can happen
regardless, but marijuana smokers, for whatever reason maybe it has
something to do with the cannabinoid receptors or the serotonin
receptors downstream of the motor pathways. I don't know. I couldn't
find any literature on this but marijuana smokers report, higher
frequency of this kind of paralysis and wakefulness as you transition
from sleep to wakefulness. I suppose probably one could learn to get
comfortable with it. For me, it was terrifying, 'cause I'm just used
to being able to move my limbs fortunately and I wasn't able to, and
it's a quite a thing, let me tell you, okay. some other questions
about neuroplasticity. So the other form of neuroplasticity is not the
neuroplasticity that you're amplifying by listening to tones or
smelling odors in sleep, but the neuroplasticity that you can access
with non sleep deep rest.
So NSDR, non sleep deep rest as well as short 20 minute naps, which
are very close to non sleep deep rest because people rarely drop into
deep States of sleep during short naps, unless they're very sleep
deprived. NSDR has been shown to increase rates of learning when done
for 20 minute bouts for a proxy- to match an approximately 90 minute
about of learning. So what am I talking about? 90 minute cycles are
these ultradian cycles that I've talked about previously. And we tend
to learn very well by taking a 90 minute cycle transitioning into some
focus mode early in the cycle, and it's hard to focus and then deep
focus and learning feels almost like agitation and strain and then by
the end of that 90 minute cycle, it becomes very hard to maintain
focus and learn more information. There's a study published in Cell
Reports last year. Great journal, excellent paper showing that 20
minute naps or light sleep of a sort of non sleep deep rest taken
immediately after or close to it, doesn't have to be immediately after
you finished the last sentence of learning or whatever it is, or bar
of music. But you know, a couple of minutes after transitioning to a
period of non sleep deep rest, where you're turning off the analysis
of duration path and outcome has been shown to accelerate learning to
a significant degree. Both the amount of information and the retention
of that information. So that's pretty cool, because this is a cost-
free, drug-free way of accelerating learning without having to get
more sleep. But simply by introducing these 20 minute bouts. I would
encourage people if they want to try this to consider the 20 minutes
per every 90 minutes of ultradian learning cycle, there you're
incorporating a number of different neuroscience backed tools 90
minute cycles for focused learning. It could be motor, it could be
cognitive, it could be musical, whatever, and then transitioned to a
20 minute non sleep deep rest protocol. I just want to cue you the
fact that in last` episode in the caption on YouTube, we provided
links to two different yoga nidra, non sleep deep rest protocols as
well as hypnosis protocols that are clinically backed from my
colleague David Spiegel at Stanford Psychiatry Department. All those
resources are free. There are also a lot of other hypnosis scripts out
there. I like the ones from Michael Sealey S-E-A-L, I think it's E-Y,
maybe it's just L-Y, you can find them easily on YouTube, clinical
hypnosis scripts meaning not stage hypnosis. They're not designed to
get you to do anything. In fact they're just designed to help rewire
your brain circuitry. Now, how does hypnosis work that way? This has a
lot to do with sleep because it engages neuro-plasticity by bringing
together two things that normally are separate from one another, one
is the alert focused wakeful state where you activate the learning.
And then there's the deep rest where the actual reconfiguration of the
neurons and synopsis takes place. Hypnosis brings both the focus and
the deep rest component into the same compartment of time. It's a very
unique state in that way. So hypnosis kind of maximizes the learning
about and the non sleep deep breasts bow and combines them. But of
course that requires some guidance from a script or from a hypnotist
clinically, a trained hypnotist and it becomes hard to acquire
detailed information. It's more about shifts in state, like fear to
states of calm or smoking to quitting smoking, anxiety around a trauma
to release of anxiety around a trauma rather than specific information
learned in hypnosis, okay? So hypnosis seems more about modulating the
circuits that underlie state as opposed to specific information.
Although I would not be surprised if there weren't certain forms of
hypnosis that could increase retention and learning of specific
information, but I'm not aware of any of those protocols out there
yet. Which brings us to the next thing about learning and plasticity
which is nootropics, AKA smart drugs. [sighs] This is a big topic that
sigh was a sigh of concern about how to address nootropics in a
thorough enough, but thoughtful enough way.
Look, I have a lot of thoughts about nootropics. First of all, it
means smart drugs, I believe. And I don't like that phrase because
let's just take a step back and think about exercise. You just say, I
want to be more physically fit. What does that mean? Does it mean I
would ask for more specificity, I'd say, Do you want to be stronger?
Okay, maybe you need to lift heavier objects progressively. Do you
want more endurance very different protocol to access endurance. Do
you want flexibility? Do you want explosiveness or suppleness? Huge
range of things that we call physical fitness. Maybe you want all of
those. If we were talking about emotional fitness we would say, well,
inability to feel empathy but probably also to disengage from empathy
because you don't want to be tethered to other people's emotions all
the time. That's not healthy either. You would think about being able
to access a range of emotions, but for some people their range into
the sadness regime is really quite vast but their range into the
happiness regime might be kind of limited. For other people who are in
a manic state, it might be, they can access all that happy stuff but
not the sadder stuff. So I'm speaking by way of analogy here. But if
we say we're talking about cognitive and cognitive abilities we have
to ask, okay, creativity, memory. We tend to associate intelligence
with memory. And I think this goes back to like spelling bees or
something, the ability to retain a lot of information and just
regurgitate information which will get you some distance in some
disciplines of life. But it won't allow you creative thinking, it's
necessary for creative thinking. You need a knowledge base, right? You
can't just look up everything on Google, despite what you know,
certain educators or so-called educators say, you need a database so
that you can have the raw materials with which to be creative. So
necessary to have memory but not sufficient to be creative, right? The
creative could have a poor memory for certain things but certainly not
for everything. They can't have anterograde and retrograde amnesia.
They'd be like the goldfish that every time around the tank, it, you
know I can't remember where it's at. I actually don't know that
they've ever done that experiment by the way, but you know, so no
disrespect to goldfish but you know, so you get the idea. You've got
creativity, you have memory, you have the ability to task switch,
right? You have the ability to strategy development, strategy
implement. So the problem I have with the concept of a nootropic or a
smart drug is it's not specific as to what cognitive algorithm you're
trying to engage. We need more specificity. That said, there are
elements to learning that we've discussed here before that are very
concrete things like the ability to focus and put the blinders on to
everything else that's happening in around you and in your head
mainly, right? Distractions about things you should be doing, could be
doing or might be doing and focus on what you need to do. And then
that's required for triggering the acetylcholine neuromodulator that
will then allow you to highlight the particular synopsis that will
then later change in sleep. So no nootropic allows you to bypass the
need for sleep in deep rest. That's important to understand. So I
daydream about a day when people will be able to access compounds that
are safe, that will allow them to learn better meaning, to access
information, focus better, as well as to sleep better and activate the
plasticity from the learning about. Right now most nootropics tend to
bundle a bunch of things together. Most of them include some form of
stimulant, caffeine. Episode two, I'll tell you more probably than you
ever wanted to know about caffeine, adenosine and how that works. So
refer there for how caffeine works. But stimulants will allow you to
increase focus up to a particular point. If you have too little
alertness in your system, you can't focus, too much however, you start
to cliff and focus drifts, okay? So you can't just ingest more
stimulant to be more focused. It doesn't work that way. Most
nootropics also include things that increase or a desire to increase
acetylcholine. Things like alpha GPC and other things of that sort.
And indeed, there's some evidence that they can increase
acetylcholine. I refer you again to examine.com the website to
evaluate any supplements or compounds for their safety and their
effects in humans and animals, free website as well as with links to
studies. So we need the focus component. We need the alertness
component. The alertness component comes from epinephrin,
traditionally from caffeine stimulation. The acetylcholine stimulation
traditionally comes from Coleen donors or alpha GPC, things of that
sort. And then you would want to have some sort of off switch, because
anything that's going to really stimulate your alertness, that then
provides a crash. That crash is not a crash into the deep kind of
restful slumber that you would want for learning, it's a crash into
the kind of, let's just call it lopsided sleep, meaning it's deep
sleep but it lacks certain spindles and other elements of the
physiology sleep spindles, that really engage the learning process and
the reconfiguration of synopsis. So right now, my stance on nootropics
is that maybe, maybe for occasional use, provided it's safe for you,
I'm not recommending it, but in general it tends to use more of a
shotgun approach than is probably going to be useful for learning and
memory in the long run. A lot of people ask about Modafinil or
armodafinil which was designed for treatment of narcolepsy. So right
there, it tells you it's a stimulant. And yes, there is evidence, it
will improve learning memory. Modafinil is very expensive. Last time I
checked our Modafinil I think is the recent released a generic version
of this that's far less expensive. Most of these things look a lot
like amphetamine and many of them have the potential for addiction or
can be habit forming. But more importantly, a lot of those things also
can create metabolic effects by disruption to insulin receptors and so
forth. So you want to approach those with a strong sense of caution.
Now, there are the milder things that act as nootropics that I
mentioned, some of them like alpha GPC. Some people like Gingko.
Gingko gives me vicious headaches, so I don't take it. So people
really differ. Last podcast, I recommend magnesium threonate if you
were exploring supplements I'm not recommending anything directly. I'm
just saying if you're exploring supplements, magnesium threonate seems
among the magnesiums to be one of the more bioavailable and useful for
sleep. I recommended it actually to a good friend of mine, it gave him
at very low dose, he had stomach issues with it.
He just had to simply stop taking it. So there's variability there.
You just, it gave him some stomach cramping and just didn't feel good
on it. Stopped it, he felt better. Other people take magnesium
threonate and feel great. I was asked, do magnesium need to be taken
with or without food or before sleep? If you're going to go that route
it should be taken 30 to 60 minutes before sleep, 'cause it's designed
to make you sleepy. And I'm not aware that it has to be taken with
food, but again all of this has to be run by your doctor and this is
your healthcare to govern not, these are not strict recommendations so
look into it. But magnesium threonate, most people I recommend it to
have benefit from it tremendously. Some people can't tolerate it, so
you have to find out. There were a number of questions about other
supplements designed to access deep sleep, in part to access
neuroplasticity, but now I'm just sort of transitioning from
neuroplasticity to these compounds that can regulate sleep. One of
them that I discussed at the end of the last podcast, I got a lot of
questions about is apigenin A-P-I-G-E-N-I-N, apigenin.
If you will look in the literature the way it works is it increases
some of the enzymes associated with GABA metabolism. It actually,
GABA's an inhibitory neurotransmitter. It's the neurotransmitter that
is increased after a couple alcohol drinks containing alcohol. And
that shut down the forebrain. Apigenin is a derivative of the
camomile. I think that the proper pronunciation of this is metric
caria kemo mila. Although I always feel like I should be using a
Spanish accent. Whenever I say something like that other related
things that impact the GABA system and increase GABA or things like
passion flower which is [speaks in foreign language]. [chuckles] I
don't know why the Italian, is that Italian. Anyway, my Italian
colleagues, please forgive me. I have some very close Italian friends
and colleagues in Genoa. I butchered the Italian, sorry. In any event
apigenin and passion flower found in a lot of, a lot of supplements
designed to increase sleepiness and sleep because, and they work
presumably because they increase GABA. Actually they work on chloride
channels rather than give you a whole lecture on membrane biophysics
in neurons. I'll just say that when neurons are really active it's
because sodium ions, salt rushes into the cells and causes them to
fire electrically. The cells tend to become less active as more
chloride which is a negatively charged ion. This is probably taking
some of you back to the either the wonderful times or traumas of high
school physics. The chloride is negatively charged so, it tends to
make cells less electrically positive, 'cause carries a negative
charge and hyperpolarizes the neuron. So apigenin works through these
increasing the activity of these chloride channels. Passionflower
works by increasing the activity of these chloride channels and GABA
transmission. It tends to increase this inhibitory neurotransmitter
that shuts off our thinking our analysis of duration path and outcome.
So if you're going to explore these things I suggest you at least know
how they work. You at least go to examined.com that you talked to your
doctor about them. Some people asked about serotonin for getting to
sleep and staying asleep. Now I understand the rationale here. Just
like I understand the rationale of taking something like Macuna Purina
or L-DOPA to increase dopamine but sometimes what works on paper
doesn't really work in the real world.
I personally have tried taking a supplement which was Al tryptophan,
which is the precursor to serotonin or five HTP, which is designed to
increase, it is serotonin basically. You're just a one biochemical
step away from actually taking actual serotonin. And I'll be honest
the sleep that I had with increased serotonin by way of tryptophan or
five HTP was dreadful. I fell asleep almost immediately. You say,
well, that's great. And 90 minutes later, I woke up and I couldn't
sleep almost for 48 hours. Now that was me, I have a pretty sensitive
system to certain things and not to other things. Some people love
these things. So you really have to be thoughtful and explore them
with that kind of awareness of being thoughtful and realizing that
what works for you might not work for everybody and what works for
everybody might not work for you. Okay? I'd like to continue by
talking about the role of temperature in sleep, accessing sleep,
staying asleep and wakefulness.
But first I want to tell a joke. Because I think this joke really
captures some of the critical things to understand about any self-
experimentation that you might do. So this is a story that was told to
me by a colleague of mine who's now a professor of Caltech not to be
named. So there's a scientist and they're in their lab. And they're
trying to understand how the nervous system works. So they go over to
a tank and they pick up a frog, and they take the frog and they put it
down on the table And they clap. [claps] And the frog jumps. So they
think for awhile, they pick up the frog, okay. They go over to the
cabinet and they take out a little bit of a paralytic drug and they
inject it locally into the back leg, set it down and clap. [claps] And
the frog jumps, but it kind of like jumps to the side a little bit.
They pick it up, they inject the paralytic into the other back leg.
They clap again, the frog jumps, but it really doesn't jump well that
time, it kind of drags itself forward. So they pick it up and they
inject the paralytic into the remaining two legs. They set it down and
they clap and the frog doesn't jump. And they go, "Oh my goodness! The
legs are used for hearing." Now they publish the paper. Paper comes
out in a great journal, news releases. It's a really big deal, their
career takes off. 20 years later, a really smart graduate student
comes along and says, "Yeah but that's loss of function. It doesn't
really show gain of function." So let's take a closer look. So they
repeat the first experiment and checks out, everything happens the
same way, but then they take the frog and they inject a drug into all
four legs that turns off the paralytic, right? It's an antagonist.
They set the frog down, they clap, and the frog jumps and they go, "Oh
my goodness! It's true. The legs really are for hearing." Now, first
of all, I want to make the point that this is not to illustrate that
science is not a good practice, it is. We need to do loss of function
and gain and function experiments. But just to show that correlation
and causation is complicated. You need to do a variety of control
experiments, and you really need to figure out what works for you. And
so while science can provide answers about what works under very
controlled conditions, it doesn't and can never address all the
situations in which a given compound, a given practice will or won't
work. And it's not just individual variability is that there are a
number of different factors. You all of course know that light can
activate and shift your circadian rhythm, but so can exercise, so can
food. The last point I want to make is an important one, which is that
no frogs were hurt in the telling of this joke. Okay. So let's
continue.
I want to talk about temperature. Temperature is super interesting as
it relates to circadian rhythms and wakefulness and sleep. First let's
take a look at what's happening to our body temperature across each
24-hour cycle. In general, our temperature tends to be lowest right
around 4:00 AM and starts creeping up around 6:00 AM, 8:00 AM and
peaks sometime between 4:00 PM and 6:00 PM. Now that varies from
person to person, but in general if we were to continuously monitor or
occasionally monitor temperature that's what we would see. Now what's
interesting is that even in the absence of any light cues or meal
cues, we would have a shift. We would have an oscillation or a rhythm
in our temperature. They would go from high to low. This is why the
idea that we're all 96.8 and that's our correct temperature. Forget
that. That is no longer true. It never was true. It depends on what
time of day you measure temperature. However, there is a range which
is within normal range, I think most of us associate fever with
somewhere around 100, 101 103, that's concerning. And we will be very
concerned if temperature drop too low as well. The way that the
temperature rhythm that's indogenous, that's within us and rhythmic no
matter what, the way it gets anchored to the pattern I described
before, or being lowest at 4:00 AM and increasing again around,
through the day until about four to 6:00 PM is by way of entrainment
or matching to some external cue, which is almost always going to be
light, but also exercise. Now you may have experienced this
temperature rhythm and how quickly it can become uninterested or it
can fall out of entrainment. Here's an experiment I wouldn't want you
to do but you've probably experienced this before, where you wake up,
it's sunny outside, and maybe you have some email or some things to
take care of or maybe you didn't sleep that well the night before and
so you stay in doors.
You don't change anything about your breakfast, you don't change
anything about your within home temperature or anything like that. And
somewhere right around 10 or 11 o'clock you start feeling kind of
chilled, like you're cold. Well, what happened was the oscillators,
the clocks in your various tissues that are governed by temperature
and circadian rhythm are starting to split away from your central
clock mechanisms. So it's actually important that your temperature
match day length. Now there's another way in which temperature
matches, oh daytime, excuse me. There's also an important way in which
temperature matches day length in general as days get longer, it tends
to be hotter out. Not always, but in general, that's the way it is.
And as days get shorter, it tends to be colder outside. So temperature
and day length are also linked metabolically. They're linked
biologically they're linked, excuse me, and atmospherically they're
linked for the reason that we talked about before about duration of
day length and other climate features and so forth. So one of the most
powerful things about setting your circadian rhythm properly is that
your temperature will start to fall into a regular rhythm. And that
temperature has a very strong effect on things like metabolism and
when you will feel most willing and interested in exercising,
typically the willingness to exercise and engage in any kind of
activity mental or physical is going to be when that rise in
temperature is steepest. When the slope of that line is greatest.
That's why 30 minutes after waking is one of those key windows, as
well as three hours after waking. And then when temperature actually
peaks which is generally, generally about 11 hours after waking. So
this is why we say that temperature and circadian rhythm are linked
but they're actually even more linked than that. We've talked before
about how light enters the eye, triggers activation of these
melanopsin cells, which then triggers activation of the super
charismatic nucleus, the master circadian clock. And then I always say
the master circadian clock informs all the cells and tissues of your
body and puts them into a nice cohesive rhythm. But what I've never
answered was how it actually puts them into that rhythm. And it does
it two ways. One is it secretes a peptide. And peptide is just a
little protein that floats through the bloodstream and signals to the
cells. Okay, we're tuning your clock. Kind of like a little, we know
watch store, the watch store owner would tune the clocks. But the
other way is it synchronizes the temperature under which those cells
exist. So temperature is actually the effector of the circadian
rhythm. Now this is really important because changes in temperature by
way of exercise, by way of eating, but especially by way of exercise
can start to shift our circadian rhythm pretty dramatically. But let's
even go to in a more extreme example. Nowadays, there's some interest
in cold showers and ice baths, not everybody is doing this I realize.
People seem to either love this or hate this. I don't mind the cold
dunk thing. I get regular about this from time to time and I'll do it.
I haven't been doing it recently. It's always painful to do the first
couple of times then you get kind of used to it. However, I've taken
people to a cold, dunk or an ice bath. I have a family member who
wouldn't get in literally passed her toes. She was like, this is just
too aversive for me. Some people really like the cold, people very
tremendously. Getting into an ice bath is very interesting because you
have a rebound increase in thermogenesis. Now you should know from the
previous episode that as that temperature increases, it will shift
your circadian rhythm and which direction it shifts your circadian
rhythm will depend on whether or not you're doing it during the
daytime or late in the day. If you do it after 8:00 PM, it's going to
make your day longer, right? Because your body and your central clocks
are used to temperature going up early in the day and throughout the
day and peaking in the afternoon. If you then increase that further or
you simply increase it over its baseline at 8:00 PM after temperature
was already falling, even if it's just by a half a degree or a couple
of degrees or you do that with exercise doesn't have to be with the
ice bath, you are extending, you are shifting forward your phase,
delaying your clock. You're convincing your clock and therefore the
rest of your body that the day is still going, right? You you're
giving it the perception, the cellar and physiological perception that
the day is getting longer. And you will want to naturally stay up
later and wake up later. Now you might say, "Wait I do an ice bath
late at night, and I feel great. And I fall deeply asleep." Well, cold
can trigger the release of melatonin. There's a rebound increase in
melatonin. So that could be the cause of that effect. You have to see
what works for you, but if you do the ice bath early in the day and
then get out you will experience a more rapid rise or cold shower
early in the day, a more rapid rise in your body temperature that will
phase advance your clock and make it easier to get up early the
following day. So for those of you that are having trouble getting up
and this is going to almost sound laughable but a cold shower first
thing in the morning will wake you up, but that's waking you up in the
short term because of a different mechanism which I'll talk about in a
moment, but it also is shifting your clock, it's phase advancing your
clock in a way that makes you more likely to get up earlier the next
day, okay? So in other words, increasing your temperature by getting
in an ice bath or cold shower or exercising which causes a
compensatory increase in body temperature. Think about the normal
pattern of body temperature. Low around 4:35 AM starts to peak right
around waking start, excuse me, starts to increase right around waking
then steep slope, steep slope to a peak around four to 6:00 PM and
then drops off. If you introduce an increase in body temperature by
way of cold exposure early in the day, let's say 6:00 AM or 5:00 AM if
you're masochistic enough to get into a cold shower at that time more
power to you, it's going to make, you want to wake up about half hour
to an hour earlier the next day than you normally would. Whereas if
you do it while your temperature is falling, it will tend to delay and
make your body perceive as if the day is getting longer. These are
phase advances and phase delays. We're going to get into this in far
more detail when we talk about jet lag and shift work in episode four
as well as other other things. But temperature is, again is not just
one tool to manipulate wake up time and circadian rhythm and
metabolism. It is the effector. It is the way that the central
circadian clock impacts all the cells and tissues of your body. If you
want to read further about this and you're really curious about the
role of temperature work by Joe Takahashi who used to be at
Northwestern University and is now at UT Southwestern in Dallas,
incredible scientist and has really worked out a lot of the mechanisms
around temperature in circadian rhythms. You can just Google his name
and you'll see a whole bunch of studies there. I want to talk about
cold and cold exposure because there's a great misconception about
this that actually you can leverage once you understand how to use
cold to either increase thermogenesis and fat loss, metabolism, or you
can use it for stress, mitigation and mood. And it really depends on
one simple feature of how you approach the ice bath or cold shower. If
you get into an ice bath or cold shower and you are calming yourself
you're actively calming the autonomic nervous system. Maybe through
some deep breathing, maybe through visualization, maybe you sing a
song. You know, people do this stuff. They use various tools. Some
people find paying attention to an external stimulus is more helpful.
You know, thinking about something not the experience of the cold,
other people find that directly experiencing the cold in its most
intense form and kind of "going into the cold" is the best way to
approach it. It really varies for people. There's no right or wrong
way to go about this. But the goal of using cold exposure for stress
inoculation and to raise your stress threshold to be able to tolerate
heightened levels of real life stress, not the ice bath, but real life
stress like work stress and relational stress, et cetera is by
suppressing the activation of the so-called sympathetic nervous
system, meaning the alertness or stress system. That involves
buffering or trying to resist the shiver response. The shiver response
is an autonomic response designed to generate heat, presumably, and
actually that is what it does in order to counter the cold. So when
you use cold exposure and you're kind of muscling through it, or
you're learning to relax within it as a form of stress inoculation,
that's great and works quite well for that purpose. And there's a
reason why cold exposure is used in a variety of forms of military
stress inoculation, most famous of which of course is the Navy seal
buds, a strep test really, which is screening procedure for becoming a
seal involves a lot of exposure to cold water. However, if you're
interested in using cold exposure for fat loss and thermogenesis, you
want to do the exact opposite thing. There was a paper published in
nature two years ago which showed that cold induced shiver, the actual
physical shiver activates the release of a chemical in the body from
muscle called succinate S-U-C-C-I-N-A-T-E. Succinate travel in the
bloodstream and then goes and activates a particular category of fat
not the typical kind pink or white fat that we think of is like
blubber in humans. That the stuff that people will seem to generally
want less of, except for those genetic freaks that seem to have none
of it depending what they consume. Congratulations. Brown fat is
called Brown fat because it's actually dark under the microscope. It's
rich with mitochondria and it exists mostly between the scapulae and
in the upper neck. And it generates thermogenesis and heat in the
body. It's rich with a certain category of agile anergic receptor, in
insanely epinephrin binds to adrenergic receptors. These Brown fat
cells increase metabolism, it's called Brown fat thermogenesis and
cause fat burning, burning of other kinds of fat, the pink and white
fat. So what does this all mean? This means if you want to use the ice
bath in order to increase metabolism, shiver away. If you want to use
the ice bath or cold shower in order to stress inoculate, resist the
shiver and learn to stay calm or "muscle through it". I mean, I don't
know that anyone's ever really talked about this publicly because I
think the data are so new. And I think that people assume that the ice
bath or cold exposure is just one thing. Here I've talked about it
three ways to shift your circadian rhythm depending on whether or not
you're doing it early in the day while your temperature is still
rising or at its peak or after that peak, in order to extend the
perception of your day as continuing and make you want to go to sleep
later and wake up later. Now, and then the third way of course is to
either activate brown fat thermogenesis and increase metabolism. I
suppose the fourth way would be to increase stress tolerance or stress
threshold, okay? But remember, temperature is the effector of
circadian rhythms. Light is the trigger. The super charismatic nucleus
is the master circadian clock that mediates all these changes, also
influenced by non-photic influence like exercise and feeding and
things of that sort. But temperature is the effector. Now you can also
shift your circadian rhythm with eating. When you travel and you land
in a new location and your schedule is inverted 12 hours. One way that
we know you can shift your rhythm more quickly is to get onto the
local meal schedule. Now that probably has to do with two effects. One
or changes in temperature inducer, eating induced increases in body
temperature. Now you should understand why that would work as well as
eating has this anticipatory secretion of beta, of hyper cretin orexin
that I talked about it earlier. So, if this is getting a little too
down in the weeds, don't worry about it. I will get more into this in
episode four of how to shift one's rhythm. But I would love for people
to understand that light and temperature are the real heavy duty
leavers when it comes to moving your circadian rhythm and sleep times
and activity schedules and exercise and feeding can help, but really
temperature and light, with light being the primary one are the most
important when it comes to sleep and wakefulness. Many people asked
questions about food and neurotransmitters and how those relate to
sleep, wakefulness and mood, which is essentially 25 hours of content
for me to cover. But I'm going to try and distill out the most common
questions. We've talked a lot about neuromodulators like dopamine,
acetylcholine and norepinephrine. You may notice in those discussions
that the precursors to say serotonin is tryptophan. Tryptophan
actually comes from the diet. It comes from the foods that we eat.
tyrosine is the precursor to dopamine. It comes from the foods that we
eat. And then once we ingest them those compounds are circulated to a
variety of different cells and tissues, but it is true that our food
and the particular foods we can influence, things like neuromodulator
levels to some extent, it's not the only way, because there are also
enzymes and biochemical pathways that are going to regulate how much
tyrosine gets converted into dopamine and there are elements of the
dopaminergic neurons, the dopamine neurons themselves that are
electrical that have influence on this as well. But there are a couple
fair assumptions that we can make. First of all, nuts and meats in
particular red meats, tend to be rich in things like tyrosine, right?
That tells you right there, that because tyrosine is the precursor of
dopamine, and dopamine is the precursor of norepinephrine, and
epinephrine that those foods tend to lend themselves toward the
production of dopamine and epinephrin and the sorts of things that are
associated with wakefulness. Now, of course, the volume of food that
we eat also impacts our wakefulness. If we eat a lot of anything,
whether or not it's ribeye steaks, rice, or cardboard, please don't
eat cardboard, your stomach if it's very distended it will draw a lot
of blood into your gut and you will divert blood from other tissues
and you'll become sleepy. So it's not just about food content, it's
also about food volume, all right? Fasting states generally are
associated with more alertness, epinephrin so forth and fed states are
generally associated with more quiescence and relaxation, serotonin,
and the kind of things that lend themselves more towards sleep and
less toward alertness. Foods that are rich in tryptophan tend to be
things like white meat, turkey, also complex carbohydrates. So if you
like you can start experimenting depending on what foods you eat. You
can start experimenting with carbohydrate rich meals for accessing
sleep and more depth of sleep. This is actually something I personally
do. I tend to eat pretty low carbs during the day. I actually fast for
until about noon. Not because I have to work to do that, but because
I'd rather just drink caffeine and water during that time. And then
sometime around noon I can't take it anymore and I'm hungry. And I eat
and I try and eat low carb-ish unless I've worked out extremely hard
in the previous two hours, which I rarely do, although I do it
sometimes. And that meal is then designed to prolong my period of
wakefulness into the late afternoon. And then sometime around dinner
time which for me is around 6:37 PM, 8:00 PM. Sometimes as late as
9:00 PM, I tend to eat things like white meat, fish, pastas, rice,
that kind of thing. My favorite food of all for accessing tryptophan
is actually a starch. It's actually a vegetable. And it's the
croissant, which is my favorite vegetable. I don't eat those all the
time, but I love them and they seem to increase dopamine as well. I've
never actually done the mass spectrometry on a croissant, but they
definitely increase tryptophan and relaxation for me. In all
seriousness, low carbohydrate/fasted/ketogenic diets tend to lend
themselves toward wakefulness by way of increasing epinephrin,
norepinephrine, adrenaline dopamine, and things of that sort.
Carbohydrate rich meals. And I suppose we talked about meals as
opposed to diet tend to lend themselves more toward tryptophan,
serotonin and more lethargic states. There is very limited evidence
that I am aware of that carbohydrates should be eaten at one time a
day as it relates to metabolism, et cetera. I'm sure that will open up
a certain amount of debate. If you work out very hard and you deplete
glycogen, then this all changes. So some people are working out very
hard in depleting glycogen and other people are not. That gets way
outside the context of this particular podcast, but yes indeed
different foods can bias different neuromodulators and thereby can
modulate awaking or our feelings of lethargy and sleepiness.
There are a couple effects of food that are independent or I should
say a couple of facts of eating, 'cause the food won't do it when it's
sitting across the table, but of eating that are powerful for
modulating circadian, rhythm, wakefulness, et cetera. And that's
because every time we eat we get eating induced thermogenesis
regardless of what we eat. Now that eating induced thermogenesis and
increase in metabolism, which is an increase in temperature really, is
probably greatest for amino acid rich foods like meats, but also other
types of foods. It's a minimal increase in body temperature compared
to say cold exposure or exercise. Now, whether or not it's a quarter
of a degree or half a degree or a degree, it really depends on the
individual. And of course there are blood sugar effects. There are
things like whether or not you are type one or type two diabetic,
whether or not you're insulin resistant, whether or not like there's a
kid who interns on the podcast here, who's 17 years old and I'm
convinced that he can eat anything and he just seems to like burn it
up and he's growing it every time. Actually the other day, he walked
into the other room and two days later, he walked out of the same
room. He came out in between of course, but and I was like, you're
grow? And he was like, you know, but he's at that stage where he's
just growing. Food is going to affect a teenager very differently than
it's going to affect a full-grown person. So, in general, starchy
carbohydrates, white meat, such as turkey, some fish increased
tryptophan, therefore serotonin, therefore more lethargic states more
calm. Meat, nuts and there are probably some plant-based foods that
I'm not aware of and I apologize, I should read up on this that also
are high in tyrosine that can increase things like dopamine,
norepinephrine, epinephrin alertness. So you can vary these however
you like. Most people I think are eating a variety of these things in
a given meals. And there are other parameters of nutrition that are
important too. Volume of food for the reasons that I mentioned before,
the volume of food in the gut, less food in the gut whether or not
it's empty or a small amount of food which tend to correlate with
wakefulness. Large volumes of food of any kind will tend to correlate
and drive the calming response and that's by way of this nerve pathway
called the vegas. We actually have sensory fibers in the gut that
communicate to a little protrusion of neurons that sit right next to
the juggler called the nodose ganglia N-O-D-O-S-E unlike Costello,
it's no dose right now he's all dose.
Nodose actually means having many protrusions and it's like kind of a
lumpy collection of neurons. A ganglia is just a collection of
neurons. And then it goes into the brain stem and then forward in the
brain to the areas of the brain they're involved in production of
various neuromodulators. So what we eat and the volume of food are
both signaling to the brain. It's not just one or the other. And then
there's also this eating induced thermogenesis. And now, you know,
from the discussion about temperature that if you're eating early in
the day you're tending to shift your rhythm earlier. So that you'll
want to wake up earlier the next day if you're eating very late in the
day, even if you can fall asleep after that, there's a tendency for
you to want to sleep later the next day. Now this of course is all
going to be constrained by when your kids need to eat, and when your
spouse needs to eat, and when your friends need to eat, or if you live
alone or what other things you're doing, if you're like me and you
kind of don't eat until noon then eat sometime around noon. And then
I'm terrible about meals. I just start eating the ingredients while
I'm supposed to be cooking and then eventually they're all gone and I
guess that's a meal. It varies. Some people are neurotically attached
to a particular meal schedule. Some people are not. I take my light
exposure schedule far more seriously than I take my meal schedule.
Although in general, try and eat healthy foods for the most part
croissants included. I was asked several times whether or not men and
women or males and females differ in terms of these neurotransmitter
phenotypes and the rhythms of sleep and temperature, or we could
probably devote a whole month and we probably will devote an entire
month to what are called sex differences because those tend to be
related to things we absolutely know like XX, or XY chromosomes or XYY
in some cases are double X chromosomes as opposed to gender, sex and
karyotype as we call it genetic makeup is crystal clear. There are
things that correlate with one or the other but it's complicated and
it's not something that's been explored in what I think is enough
detail. Actually recently, I guess it was about five years ago, the
national institutes of health made it a mandate that all studies use
sex as a biological variable, and actually explore both sexes of mice,
both sexes of humans when doing any kind of study because there was a
bias towards only using male animals or male subjects prior to that
time. So a lot of data now coming out revealing important sex
differences that I think are going to have powerful impact on health
practices, et cetera. Response to drugs, response to just different
sleep schedules, et cetera. Perhaps the most salient and obvious one
is that during pregnancy females experience a whole range of endocrine
and neuro effects and we definitely will devote a month to pregnancy
and childbirth and child rearing. And for that, I'd really like to
bring in some experts. I've got terrific colleagues at Stanford and
elsewhere that work on these things, so that we can go into those in
more depth. So I'm not blowing off those questions. I'm just, I'm kind
of pushing them down the road a little bit where I can give you a more
thorough answer. So as we finish up, I just want to offer you the
opportunity to do an experiment. We've talked about a lot of variables
that can impact sleep and wakefulness.
And in keeping with the theme of the podcast we are going to continue
to talk about sleep and wakefulness and tools for those, and the
science behind those tools as we go forward. But there are really just
four simple parameters that you have control over, that you can
immediately start to record and take note of just to see how you're
doing with these things. With no judgment or perhaps no change to what
you're actually doing. It might be interesting, just a suggestion to
write down for each day when you went outside to get sunlight and when
you did that, relative to waking. So you would write down, like the
way I do this in my calendar is I'll write down that I don't get exact
about it. I might say, I woke up at 6:15 and then I, as I'll put a W
6:15, and then SL for sunlight and you'll sometimes get outside right
away. Other times I'm less good at that. And I'll go out around, let's
say seven and for how long, I don't maybe like 10, 15 minutes or so.
And then I'll put a little check at the times that I eat my so-called
meals. Although, as I mentioned, sometimes my meals are a bunch of
small checks that just kind of extend through the late hours of the
day. Yours might be more confined to certain times. And then you might
just take note of when you exercised, just put down an E for when you
exercise. Weight training or aerobic exercise. And you might note when
you might've felt chilled or cold if you do, or you might've felt
particularly hot, or if you woke up in the middle of night, when you
felt particularly hot. And then the last thing you might want to do is
just write down if and when you did a non sleep deep rest protocol, an
STR protocol, that could be meditation, that could be yoga nidra, that
could be hypnosis. Anything that you're using to deliberately teach
your nervous system, how to go from more alertness to more calmness in
the waking state, even if it's waking up in the middle of the night
and doing an SDR protocol or in the afternoon, or first thing in the
morning to recover some sleep and ability to perform DPOs that you
might've lost from a minimal or poor night's sleep. So you're going to
rite down when you woke up, when you viewed sunlight, that might be in
the morning and the evening, or just the morning, hopefully it's the
morning and the evening, when you exercised, when you eat your meals
and using a simple record keeping scheme like W for waking, SL for
sunlight maybe you come up with a system where it's a check or an X or
something for exercise. This is not designed to make you neurotically
attached to tracking all your behaviors and everything you do. I for
instance, don't track what I eat. In particular, I kind of know what
works for me and I'd just try and stay within that range. But by doing
this you can start to reveal some really interesting patterns.
Patterns that no answer that I could provide you about any existing
tool or protocol could counter. It's really about taking the patterns
of behaviors, of waking, and light viewing, and eating, and exercise
and superimposing that on what you're learning in this podcast and
elsewhere of course and what you already know and trying to see where
certain problem or problems or pain points might be arising. Maybe
you're eating really late in the day and you're waking up in the
middle of the night, really warm. Well, now you would say, "Well, that
could be due to kind of an increase in temperature that is extending
my day or maybe you start to find that using cold exposure early in
the day is great for you, but using it late, if it's too late in the
day, that's not great. Or if you're into the sauna or it's even like
some people, including myself, if I take a hot shower or sit in a hot
tub or a sauna late at night, well then I get a compensatory decrease
in body temperature and I sleep great provided I hydrate well enough,
'cause that can be kind of a dehydrating thing to sit in hot, hot
conditions. But if I do the sauna early in the day, unless I exercise
immediately afterward then I tend to get the temperature drop, which
makes sense because when you get in the sauna, you're get
vasodilation. You throw off a lot of heat and then you generally get a
compensatory drop in temperature. If you do that early in the day,
that's right about the time that temperature is trying to entrain the
circadian clocks of your body. That's what happens to me. Other
people, it might be slightly different and some people have more
resilient systems than others. So I just encourage you to start
becoming scientists of your own physiology of your own brain and body
and seeing how the various tools that you may or may not be using are
effecting your patterns of sleep, your patterns of attention and
wakefulness. It's vitally important that if you do this, that you know
that it's not about trying to get onto an extremely rigid schedule,
it's really about trying to identify variables that are most powerful
for you, and that push you in the direction that you want to go. And
changing the variables that are pushing your body and your mind in the
directions that you don't want to go. Self experimentation is
something that should be done slowly, carefully, you don't want to be
reckless about this. And this is where I would say manipulating one or
two variables at a time is really going to be best as opposed to
changing of a dozen things all at once to really identify what it is
that's most powerful for you. As always, thank you so much for your
questions. We are going to continue to answer questions. I certainly
didn't get to all of them but we tried to get to most all of the ones
that were frequently asked. Episode four of the podcast, I'm going to
get into, shift work, jet lag and age dependent changes in sleeping
and wakefulness and cognition. So for those of you with kids, for
those of you that are kids for those of you with older relatives or
who might be older meaning probably when you start to get into late
'60, '70 and '80 is when there's some marked biological shifts in
temperature regulation and things that relate to sleep. And for those
of you that travel, we're going to talk about jet lag. The shift work
discussion might seem only relevant to those that work nights, but
actually that's not the case. Most people because of the way they're
interacting with devices are actually in a form of shift work now,
where the days are certainly not nine to five, the so-called banker's
hours, and then the lights are out at nine and they're asleep until
5:00 AM. Some people have that schedule, most people do not. So
episode four, we will go deeply into shift work, jet lag age dependent
changes in sleep alertness and cognition and I will touch back on a
few of your questions but don't think that if your question wasn't
answered during these office hours that we won't get to it, I
absolutely will at some point. In addition to that, several of you
have graciously asked how you can help support the podcast. And we
very much appreciate that. You can support the podcast by liking it on
YouTube, by subscribing on YouTube, by recommending the YouTube videos
to others, as well as subscribing and downloading the podcast on Apple
where you can also leave a review and on Spotify, we're all three, if
you like. you can also help us by supporting our sponsors. So check
out some of the sponsor links that were described at the beginning of
the episode. And in general, recommending the podcast to people that
you know and that you think would benefit from the information would
be terrific. As always I will be continuing to post on Instagram. You
can expect another podcast episode out next Monday about the topics
that we've been discussing this month and above all, [upbeat music]
thank you for your interest in science.
Thank you to our sponsors:
* Athletic Greens - http://athleticgreens.com/huberman
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Timestamps below.
0:00 - Introduction
5:50 - Moonlight & Fire
9:25 - Red Light: Good & Bad
15:45 - Why Blue-Blockers Are Unscientific
19:20 - Eyeglasses, Contact Lenses & Windows
22:05 - Adding Up Your Lights
24:30 - “Netflix Inoculation” With Light
25:25 - How The Planet Controls Your Energy
27:00 - A Season For Breeding (?)
31:15 - Melatonin / Serotonin
33:50 - Epinephrine vs Adrenaline: Same? Different?
35:00 - Exercise & Your Sleep
40:30 - Neuroplasticity & Food/Chemicals/NSDR
44:10 - Using Sound & Smell To Learn Faster
46:45 - Dream Meaning & Remembering
48:15 - Waking Up Paralyzed
49:40 - Nap/Focus Ratios For Accelerated Learning
52:45 - Hypnotizing Yourself
54:05 - Smart Drugs
1:01:10 - Magnesium: Yay, Nay, or Meh?
1:02:10 - How Apigenin Works
1:04:30 - Serotonin: Slippery Slope
1:05:35 - The Frog Experiment
1:08:35 - Temperature
1:10:30 - Morning Chills
1:28:00 - Eating For Heating
1:30:30 - Vagal Pathways For Gut-Brain Dialogue
1:31:50 - Sex Differences
1:33:50 - Self Experimentation
As always, thank you for your interest in science!
Please note that The Huberman Lab Podcast is distinct from Dr.
Huberman's teaching and research roles at Stanford University School
of Medicine. The information provided in this show is not medical
advice, nor should it be taken or applied as a replacement for medical
advice. The Huberman Lab Podcast, its employees, guests and affiliates
assume no liability for the application of the information discussed.
[Title Card Photo Credit: Mike Blabac https://www.blabacphoto.com/]