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.
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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 liked 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’s 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 always say.
It sounds like boilerplate,
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.
what is the role of moonlight and fire?
I’m presuming they mean fireplace or candle
or things of that sort, in setting circadian rhythms.
Is it okay to view moonlight at night
or will that wake me up?
Will a fire in my fireplace or using candlelight
be too much light?
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 lux,
which sometimes are also described in terms of candelas.
So those are the two units for measuring light intensity.
Typically lux, L-U-X, 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 meter’s 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.
Turns out that moonlight, candlelight,
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 convey 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 a lot of people have 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 if the moon is really full and really bright,
there’s possibility for that.
So provided you’re not going to burn down
the structure you’re in,
you’re not going to burn down the forest,
enjoy 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 p.m. and 4 a.m.,
except when you need to view things for sake of safety
or work 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.
I’m going to be really honest,
and I can’t name brands,
and I’m not going to name particular studies,
because 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 instringency level is.
Now, that’s not to say red light isn’t beneficial,
because there is one study in particular
that came from Glenn Jeffrey’s lab
at the University of College London.
It was published last year.
Glenn is somebody I happen to know.
He has an excellent reputation, excellent vision scientist.
What this study essentially showed,
and again, this is a study that I very much like 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 photoreceptor functionality
just getting worse with time,
and what Glenn 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
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 mitochondrial function in these photoreceptors,
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 lights,
it’s look at these lights potentially
if that’s what you want to do at particular times of day
and with 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
since about the science behind the blue blocker confusion.
So these melanopsin retinal cells do react to blue light,
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
failed to actually read the papers 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.
Turns out in your eye and my eye right now,
because that’s what we care about,
these cells exist and these 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 photoreceptors.
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 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
Okay, while we’re on that topic,
let’s talk about light in other orifices of the body.
I made 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 setting circadian rhythms.
You know, 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 stuff those things up your nose.
Remember earlier, previous podcast,
I said that virtually anything will phase shift
to 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 neurohacking or biohacking.
I just don’t like the term
because a hack is using something for a purpose
for which it was not intended, right?
But where you can kind of, it’s a 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 gonna 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
or publish 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 gonna 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 extraocular photoreception, 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.
And mediating a process through a hardwired
or longstanding biological mechanism
is really where you’re gonna 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,
you know, plugging in and swallowing
and, you know, 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 gonna 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 this.
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.
And 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 10,000 lux outside,
5,000 looking out through an open window,
and then I close 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
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 onto your neural retina.
In fact, that’s what nearsightedness 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.
Costello is loving this, 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 sum or add photon activation
of these 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
because it 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 your 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 neurobiological process
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 we’re 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 equator,
you experience less variation in day length
and therefore night length.
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 pole you’re at
and what time of year it is.
A simple way to put this is 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
and feel great all the time.
Unfortunately, it 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 is 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 kind 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.
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?
When am I getting that light?
Because sleep is also important for restoring mood, right?
So you need sleep.
You can’t 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 wellbeing provided to proper levels,
but wellbeing of a particular kind,
wellbeing associated with quiescence and calm
and the feeling that we have enough resources
in our immediate kind of conditions.
It’s 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 precursor to epinephrine,
to adrenaline, which actually puts us into action.
It’s actually made from dopamine, right?
So you can start to think 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 avoid bright light
in the middle of the night.
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, people that are 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,
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 bias certain brain circuits
and things in our body to happen
and certain brain circuits and things in our body
not to happen.
One of the ones I’ve mentioned numerous times
is epinephrine, 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 epinephrine and adrenaline?
Adrenaline is secreted from the adrenal glands,
which sit right above our kidneys.
Epinephrine 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 eph,
it means kidney.
So it means near the kidney.
So epinephrine actually means near the kidney.
So it was used originally to describe adrenaline,
but epinephrine 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 individual variability around this,
but I can talk about what I know from the science literature
and what I happen 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, 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, it’s been challenging to find conditions
in which mice really like to lift weights
or will 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 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 is 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-photic 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 converge
to give an 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 preceding 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 realize 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 of Chronobiology
and Journal of Biological Rhythms, excuse me,
to assess these parameters
that I mentioned 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 neural plasticity, 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 at 8 a.m., noon, and 7 p.m.
is when you eat your food, not suggesting you do this,
but let’s say you were to do that for a couple days.
After a few days, you would start to anticipate
those mealtimes 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 mealtimes,
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 hypocretinorexin,
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 hypocretinorexin 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 ultradian 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 neural plasticity.
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 NSDR, non-sleep deep rest
that can be done without sleeping
to improve rates of learning and depth of retention,
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.
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 the following way.
An individual is brought into a laboratory,
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,
there might be a cat, then it might be an apple,
then it might be a pen in different locations.
And that sounds trivially 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 the 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,
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 effect,
some 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 subjects 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,
the asleep brain to learn particular things better
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 is a safe one
and it 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 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, somatosensory 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’ll report back to you
as I learn 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
because I got so many questions about dreams.
A couple of you 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 alarm so that you wake up
in the middle of 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
because 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 later 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 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.
We’re 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,
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 move.
One is marijuana, THC.
I’m not a marijuana smoker.
I’m not a cop, or 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,
because I’m just used to being able
to move my limbs, fortunately,
and I wasn’t able to,
and it’s 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
to match an approximately 90-minute bout 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
when 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 the sort of non-sleep deep rest
taken immediately after or close to,
it doesn’t have to be immediately
after you finish the last sentence of learning
or whatever it is or bar of music,
but a couple 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,
could be musical, whatever,
and then transition to a 20-minute
non-sleep deep rest protocol.
Just want to cue you to 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’s psychiatry department.
All those resources are free.
There are also a lot of other hypnosis scripts out there.
I like the ones from Michael Sealy, S-E-A-L.
I think it’s E-Y, although 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 neuroplasticity
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 synapses 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 bout
and the non-sleep deep rest bout and combines them.
But of course, that requires some guidance
from a script or from a hypnotist,
clinically trained hypnotist,
and it becomes hard to acquire detailed information.
It’s more about shifts in state,
like fear to states of calm
or 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.
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, an ability 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 the 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 abilities,
we have to ask, okay, creativity, memory.
We tend to associate intelligence with memory.
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 certain educators or so-called educators say.
You need a database so that you could 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 interrogate and retrograde amnesia.
They’d be like the goldfish
that every time around the tank,
it can’t remember where it’s at.
I actually don’t know that they’ve ever done
that experiment by the way,
but 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 develop
and 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
onto everything else that’s happening 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
that acetylcholine neuromodulator
that will then allow you to highlight
the particular synapses that will then later change
So nootropic allows you to bypass the need
for sleep and 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 bout.
Right now, most nootropics tend to bundle
a bunch of things together.
Most of them include some form of stimulant, caffeine.
Episode two, I 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 are designed 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 epinephrine,
traditionally from caffeine stimulation.
The acetylcholine stimulation traditionally comes
from choline 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 synapses.
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 and memory.
Modafinil is very expensive.
Last time I checked, armodafinil, I think,
is the recent released 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 it 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.
I mentioned some of them, like alpha-GPC.
Some people like ginkgo.
Ginkgo gives me vicious headaches, so I don’t take it.
So, you know, people really differ.
Last podcast, I recommended 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.
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, daytime or before sleep?
If you’re going to go that route,
it should be taken 30 to 60 minutes before sleep
because 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.
These are not strict recommendations, so look into it.
But magnesium threonate,
most people I’ve recommended 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 look in the literature,
the way it works is it increases some of the enzymes
associated with GABA metabolism.
It actually, GABA is an inhibitory neurotransmitter.
It’s the neurotransmitter that is increased
after a couple drinks containing alcohol
and that shut down the forebrain.
Apigenin is a derivative of the chamomile.
I think that the proper pronunciation of this
is matricaria chamomila,
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 are things like passion flower,
which is passiflora incurata.
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 supplements
designed to increase sleepiness and sleep
and they work presumably because they increase GABA.
Actually, they work on chloride channels
rather than give you a whole lecture
on membrane biophysics and 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 either the wonderful times or traumas
of high school physics.
The chloride is negatively charged,
so it tends to make cells less electrically positive
because it carries a negative charge
and hyperpolarizes the neuron.
So apigenin works through these,
increasing the activity of these chloride channels.
Passion flower 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 examine.com,
that you talk 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 mucunipurines 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 L-tryptophan,
which is the precursor to serotonin,
or 5-HTP, which is designed to increase.
It is serotonin, basically.
You’re just one biochemical step away
from taking actual serotonin.
And I’ll be honest,
the sleep that I had with increased serotonin
by way of tryptophan or 5-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 and the frog jumps.
So they think for a while and they pick up the frog.
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 and the frog jumps,
but it kind of like jumps to the side a little bit.
Mm-hmm, 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.
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 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.
Doesn’t really show gain of function.
So let’s take a closer look.
So they repeat the first experiment and it 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.
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.
We need to do loss of function
and gain in 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.
It’s 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 a.m. and starts creeping up
around 6 a.m., 8 a.m. and peaks sometime
between 4 p.m. and 6 p.m.
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 that 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.
And we will be very concerned
if temperature dropped too low as well.
The way that the temperature rhythm that’s endogenous,
that’s within us and rhythmic no matter what,
the way it gets anchored to the pattern I described before
of being lowest at 4 a.m. and increasing again
around through the day until about 4 to 6 p.m.
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 unentrained
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 indoors.
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,
or 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 reasons 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 suprachiasmatic 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.
A 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, you know, in a 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 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
and 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 past 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 p.m.,
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 p.m.
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.
You’re phase delaying your clock.
You’re convincing your clock
and therefore the rest of your body
that the day is still going, right?
You’re giving it the perception,
the cellular 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,
excuse me, starts to increase right around waking,
then steep slope, steep slope to a peak
around four to 6 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 AM or 5 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 things.
But temperature is, again,
it’s 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,
and has really worked out a lot of the mechanisms
around temperature and 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, quote unquote,
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 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 travels in the bloodstream
and then goes and activates a particular category of fat,
not the typical kind of pink or white fat
that we think of as like blubber in humans,
the stuff that people seem to generally want less of,
except for those genetic freaks
that seem to have none of it,
depending on 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 adrenergic receptor.
Incidentally, epinephrine 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 quote unquote muscle through it.
Now, 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.
But remember, temperature is the effector
of circadian rhythms.
Light is the trigger.
The suprachiasmatic 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 are changes in temperature,
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 hypocretin 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 levers
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,
that those compounds circulate
to a variety of different cells and tissues.
But it is true that our food
and the particular foods we eat 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
that those foods tend to lend themselves
toward the production of dopamine and epinephrine
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
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, epinephrine and 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
but 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 carb-ish 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 sometimes.
And that meal is then designed to prolong
my period of wakefulness into the late afternoon.
And then sometime around dinnertime,
which for me is around 6.30, 7 p.m, 8 p.m,
sometimes as late as 9 p.m,
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, 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.
Never actually done the mass spectrometry on a croissant,
but they definitely increase tryptophan
and relaxation for me.
In all seriousness, low carbohydrate
slash fasted slash ketogenic diets
tend to lend themselves toward wakefulness
by way of increasing epinephrine, norepinephrine,
adrenaline, dopamine, and things of that sort.
and I suppose we should talk 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
and depleting glycogen, 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
our waking or our feelings of lethargy and sleepiness.
There are a couple effects of food that are independent,
or I should say a couple effects of eating,
because 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, the 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 a 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 1 or type 2 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 burn it up, and he’s growing.
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 grew.
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, epinephrine, alertness.
So you can vary these however you like.
Most people, I think, are eating a variety of these things
in given meals, and there are other parameters
of nutrition that are important too.
Volume of food, for the reason 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,
will 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 vagus.
We actually have sensory fibers in the gut
that communicate to a little protrusion of neurons
that sit right next to the jugular
called the no-dose ganglia, N-O-D-O-S-E.
Unlike Costello, it’s no-dose, right now he’s all-dose.
No-dose 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
that are 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,
when your spouse needs to eat,
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.
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, I 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.
You know, 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, or XX 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 are 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 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 kind of pushing them down on 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,
the way I do this on 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, it’s I’ll put a W, 6.15
and then SL for sunlight.
Now you sometimes get outside right away.
Other times I’m less good at that
and I’ll go out around, I don’t know, let’s say seven.
And for how long?
Maybe like 10, 15 minutes or so.
And then I’ll put a little check
at roughly 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 the 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, NSDR 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 NSDR 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 gonna write 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 ate 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 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 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 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
because that can be kind of a dehydrating thing
to sit in 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 we can get in the sauna,
you get vasodilation, you throw off a lot of heat,
and then you generally get a compensatory drop
If you do that early in the day,
that’s right about the time that 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 affecting 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
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 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
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 60s, 70s, and 80s,
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,
so-called banker’s hours, and then the lights are out
at nine and they’re asleep until 5 a.m.
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, or 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.
And as mentioned at the beginning of today’s episode,
we are now partnered with Momentous Supplements
because they make single ingredient formulations
that are of the absolute highest quality,
and they ship international.
If you go to livemomentous.com slash Huberman,
you will find many of the supplements
that have been discussed on various episodes
of the Huberman Lab podcast,
and you will find various protocols
related to those supplements.
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, thank you for your interest in science.