Huberman Lab - Find Your "Temperature Minimum" to Defeat Jetlag, Shift Work & Sleeplessness

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

to bring zero cost to consumer information

about science and science-related tools

to the general public.

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I’ve done a couple of episodes now

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Today’s podcast episode is about sleep and wakefulness.

We are going to discuss jet lag, shift work,

babies, kids, and the elderly,

and we are going to discuss protocols

that are backed by science.

That means quality peer-reviewed papers

published in excellent journals

that can support particular tools

that you can use to combat things like jet lag,

offset some of the negative effects of shift work,

and make life easier for the new parent,

as well as for the newborn child, the adolescent,

anyone that wants to sleep better,

feel better when they’re awake, et cetera.

If you’ve listened to the previous three episodes

of the Huberman Lab Podcast,

we’ve been exploring these themes

of wakefulness and sleepiness,

how to fall asleep, how to stay asleep,

and we’ve been discussing parameters

like light, exercise, temperature, et cetera.

If you’ve had a chance to listen to those episodes, great.

Today’s discussion will be even more digestible for you.

If you haven’t, that’s okay.

I will provide a little bit of background here or there

so that it’s not necessary

that you have listened to those previous episodes,

but if you get a chance to listen to them, please do.

I think it will help you digest the information better.

Let’s just take a step back for a moment

and remind everybody what we’re talking about.

We’re talking about an endogenous, meaning within us,

rhythm that we call the circadian rhythm.

The circadian rhythm is a 24-hour rhythm

in all sorts of functions.

The most prominent one is a rhythm

in our feelings of wakefulness and sleepiness.

So believe it or not,

the experiment has been done throughout history,

not often, but it’s been done

where people will go down into a cave

and will exist in constant darkness for some period of time.

There are also cases where people have been

in constant light for some period of time,

but because people can close their eyes,

it’s actually easier to do the experiment

where you’re in constant darkness

to address the question of what is the endogenous,

meaning the internal rhythm that we all have,

and it turns out we all have this rhythm of about 24 hours,

although it’s not exactly 24 hours,

meaning every 24 hours,

your body temperature goes from low to high

and back down to low again,

and it takes 24 hours for that to repeat.

Not 18, not six, 24, plus or minus a couple hours.

You also have a rhythm in sleepiness and wakefulness

that correlates with that.

We tend to be sleepy as our temperature is falling,

getting lower, and we tend to be more awake or waking

when our temperature is increasing.

This is a biological fact.

It is right down to our DNA.

We actually have genes in every single one of our cells

that ensure that every cell is on this 24-hour-ish rhythm,

close to 24 hours.

We have a clock over the roof of our mouth,

a group of neurons called the suprachiasmatic nucleus.

That clock generates a 24-hour rhythm,

and that clock is entrained,

meaning it is matched to the external light-dark cycle,

which is, no surprise, 24 hours.

Spinning the Earth takes 24 hours.

So our cells, our organs, our wakefulness, our temperature,

but also our metabolism, our immune system, our mood,

all of that is tethered to the outside light-dark cycle.

And if we are living our life in a perfect way

where we wake up in the morning

and we view sunlight as it crosses the horizon,

and then by evening we catch a little sunlight,

and then at night we’re in complete darkness,

we will be more or less perfectly matched

to the external or ambient light-dark cycle.

Very few of us do that

because of these things that we call artificial lights

and this other thing that we call life demands.

So today we’re going to talk about

when we get pulled away from that rhythm.

Now, you may immediately be thinking,

well, I’ve heard there are night owls

and there are morning larks, they’re sometimes called,

and there are genetic polymorphisms,

that’s just a fancy name for genetic variations

that make some people want to wake up early

and other people want to stay up late

and teens want to sleep in more.

Sure, that’s all true.

That’s all true regardless of what names we give those.

However, there’s no escaping the fact

that human beings are a diurnal species.

We were designed, literally,

our cells and the circuits of our body

were constructed to be awake during the daytime

and asleep at night.

How do I know that?

Well, I wasn’t consulted at the design phase,

but I’m certain of that because many studies have shown

that when we deviate too far from a diurnal schedule

and we try and become nocturnal, we can pull it off,

but serious health effects,

both mental and physical, start to arise.

I’m not going to spend much of today

talking about all the negative effects of jet lag,

I’ll talk a little bit about it,

or the negative effects of shift work

or trying to scare you by telling you

about the quite valid data around depression, amnesia,

dementia, all the terrible things that happen

when you’re not sleeping well.

Rather, I’d like to focus on what you can do

and arm you with tools.

So let’s talk about that perfect schedule for a moment,

and then let’s talk about jet lag

and what jet lag really represents

and how to push back on jet lag, shift your clock faster,

and escape some of the severe bad things

that can happen with jet lag,

including just feeling miserable

when you’re traveling for work or vacation.

So what is the perfect day?

What does that look like

from a circadian sleep wakefulness standpoint?

Well, I’m about to summarize what I’ve said

in the three previous podcast episodes,

as well as now countless Instagram posts.

Here’s the deal.

You basically want to get as much light, ideally sunlight,

but as much light into your eyes

during the period of each 24-hour cycle

when you want to be awake, when you want to be alert.

And you want to get as little light into your eyes

at the times of that 24-hour cycle

when you want to be asleep or drowsy and falling asleep.

How much is enough?

Well, you don’t want to go so high with the light exposure

that you damage your eyes

because as many of you heard me say before,

the eyes are actually two pieces of your brain,

your central nervous system

that were extruded out of your skull.

And as pieces of the central nervous system,

aka your brain, they will not regenerate.

At least right now, the technologies don’t exist

to regenerate those neurons in humans.

You do not want to damage them.

So what is too bright?

Well, when it’s painful to look at,

when you have to blink or close your eyes

in order to bear it.

So please don’t look at very bright lights,

so painful that they’re likely going to damage your eyes.

However, if you get up in the morning

and it’s still dark out and you want to be awake,

you would be wise to turn on artificial lights,

in particular overhead lights

for reasons I’ve discussed previously,

but those overhead lights will optimally trigger

the neurons, these melanopsin cells in the retina

that will activate your circadian clock.

When the sun comes out, even if there’s cloud cover,

the sun does come out every day,

regardless of where you live, unless you live in a cave.

People have said to me,

well, I live in an area where I can’t really see the sun.

Well, the sun is there.

It might be hiding behind clouds

unless it’s very, very dark where you live,

like Scandinavia in the depths of winter,

in which case you might want some artificial light.

Get some sunlight in your eyes when you can.

Here’s the deal with sunlight and artificial light

that I have not discussed previously.

A lot of photon energy, a high amount of lux,

LUX comes through even cloud cover.

A good number to shoot for as a rule of thumb

is to try and get exposure to at least 100,000 lux

before 9 a.m.

10 a.m. maybe, but before 9 a.m.,

assuming you’re waking up sometime between 5 and 8 a.m.

Okay, so get 100,000 lux.

Now you do not, I want to repeat,

you do not want to stare at a 200,000 lux

or a 100,000 lux light.

It’s very, very bright.

The mechanism of circadian clock setting,

and this is very important,

the mechanism of circadian clock setting

involves these neurons in your eye

that send electrical signals

to this clock above the roof of your mouth,

and that system sums, meaning it adds photons.

It’s a very slow system.

So let’s say that I wake up

and I look at my computer screen briefly,

or my phone screen.

That’s probably 500 to 1,000 lux.

If I were to look at that for a full minute,

I would get that photon energy

transferred into electrical energy of neurons,

and it would be communicated to my circadian clock.

However, the signal that it’s morning

will not have registered with the circadian clock,

unless I looked at that for 100 minutes or more.

So 100,000.

Now the problem is if you wake up at eight o’clock,

you’re not going to get enough light from artificial light

before you reach what’s called the circadian dead zone.

So you have this opportunity before 9 a.m., maybe 10 a.m.,

to capture enough photons,

and you have to do it with your eyes.

I’ve discussed why that’s important

in previous episodes of the podcast.

You have to do it with your eyes.

There is no extraocular photoreception.

This is not about vitamin D in your skin.

This is about setting your circadian clock,

which is paramount for mental and physical health.

So here we’re talking about trying to get that

at least 100,000 photons, but not all at once,

but you got to get them before 9 a.m.-ish, maybe 10 a.m.

So what do you do?

You go outside.

If you want to get nerdy about this, quantitative,

you could download a free app like Light Meter

and take a look around your house with Light Meter,

and you’ll notice that even bright overhead lights

are only emitting about 4,000 or 5,000 lux.

It’s going to take a long while of looking at those lights

with eyes open in order to set your circadian clock

and tell your brain and body that it’s morning.

Going outside, even on a cloudy day,

could be 7,000, 10,000 lux.

It’s really remarkable how bright it is,

meaning how much photon energy is coming through.

So try and get 100,000 lux before that 9 a.m.

Now, if you can’t do that

because you live in an area of the world

where it’s just not bright enough,

some people have sent me pictures from Northern England,

it’s just not bright enough in winter,

then sure, you can resort to using artificial lights

in order to get enough photons.

And I’m putting out this 100,000 lux number as a target

to get each day before 9 a.m.

You can, in theory, get it all from artificial lights,

but there are some special qualities about sunlight

that make sunlight the better stimulus.

First of all, it’s free if it’s available outside.

There is a number of different,

there are, excuse me, a number of different technologies,

kind of like this one, like a light pad,

that this one says it’s 930 lux.

I’m not, I’m covering this up

because I’m not trying to promote any specific products.

I actually bought this just with my own money on Amazon.

They’re not a sponsor.

And it lets you toggle the brightness, I think,

by holding this on, holding down this button,

you can make it dimmer or brighter.

This is about 1,000 lux.

It seems really bright,

but a cloudy day outside

will have five times more photon energy coming through.

So some people set these lights or ring lights

that they use for selfies and that kind of thing

near their coffee or workstation first thing in the morning,

but you really want to get sunlight, okay?

So those things are kind of nice because they’ll travel,

and we’re going to talk about jet lag,

but I can’t emphasize this enough.

That light has to be captured and summed

before you enter the circadian dead zone,

which is the middle of the day.

This is, again, trying to achieve kind of perfect schedule.

Then I’ve recommended based on scientific literature

that you look at sunlight sometime

around the time when the sun is setting.

And the reason for that, of course,

is because it adjusts down the sensitivity of your eyes

because here’s the diabolical thing.

While we need a lot of photon energy early in the day

to wake up our system and set our circadian clock

and prepare us for a good night’s sleep

14 to 16 hours later,

it takes very little photon energy

to reset and shift our clock after 8 p.m.

And that’s why you want to, as much as you safely can,

avoid bright light and even not so bright light

between the hours of 10 or 11 p.m. and 4 a.m.

A number of people have asked me some questions about this.

And the last episode, I went into red lights.

I would discuss blue blockers, all that kind of stuff.

So I’m not going to repeat all that, but here’s the thing.

If you see afternoon light,

you’re going to adjust down the sensitivity of your eyes

so that you have a little bit more wiggle room,

a little bit more leeway to view lights from screens

and overhead lights even late at night

without disrupting your circadian clock.

But it is a kind of a double-edged sword

where you need a lot of light early in the day

and you need to avoid bright lights later in the day.

I’ve mentioned studies on here.

A number of you have asked about getting the references.

We are in the process of trying to get a webpage going

with full links.

There’s some copyright issues that we have to deal with,

but wherever possible, I’ll try and reference these studies.

And when people ask, I’ll generally put them

in the response to their comments on YouTube or Instagram.

There have been two studies done

from University of Colorado,

both published in Current Biology.

You can easily find these online

by just Googling the words Current Biology,

camping and reset circadian clocks

that have shown that two days of waking up with the sun

and avoiding light at night,

they actually took graduate students camping,

really cool experiment to be a part of,

reset the melatonin and cortisol rhythms

for these people that had otherwise drifted quite far

from their natural rhythms.

There are other things that you can do to shift your clock

and to reinforce your clock,

like exercising more or less the same time,

eating more or less the same time, et cetera.

That’s not what today’s episode is about.

So I just described perfect schedule,

get at least 100,000 lux of light exposure to the eyes,

not all at once, but summing across the morning.

Again, you know when it’s too much

because it’s painful to look at.

So that’s obviously something to avoid.

But then once the middle of the day,

let’s say you’re waking up at 10 or 11,

you go outside, the sun’s overhead, forget it.

You’re not going to shift your clock.

You’re just not, it doesn’t work that way.

In the evening, you see the evening light

and you want to get that light

to adjust down your retinal sensitivity

to afford you a bit of a buffer so that late at night,

if you happen to look at screens

or go to the bathroom in the middle of the night,

it’s not going to shift your clock

because it takes probably only about 1,000 to 1,500 lux

of light energy to shift your clock

in the middle of the night.

So let’s talk about shifting clocks

because for the jet lag person,

this ability to shift the clock

with light temperature exercise and food

is vitally important for getting

onto the new local schedule.

And there’s so much out there about jet lag today.

I’m going to dial it down to one very specific parameter

that all of you can figure out

without any technology or devices

and can apply for when you travel for work or pleasure

or anytime you’re jet lagged.

And I want to absolutely emphasize

that you don’t have to travel to get jet lagged.

Many of you are jet lagged.

You’re jet lagged because you’re looking at your phone

in the middle of the night.

You’re jet lagged because you’re waking up

at different times a day.

You’re jet lagged because your exercise

is on a chaotic regime some days at this time,

some days at that time.

And if that works for you, great.

I want to be really clear that a number of people

always say, well, I know so-and-so

that only needed four hours of sleep

and or they’re just fine.

They traveled to Europe and it’s just fine.

There’s a lot of individual variability.

And we’re going to talk about the origins

of some of that variability.

I mean, I know people that can eat anything

and somehow seem to maintain great lipid profiles

and body weight and fitness ability.

And I know some people that they eat one cracker

and they sort of dissolve into a puddle of kind of tears

because they think that that’s going to throw them off.

And then maybe it does, I don’t know.

There’s a tremendous amount of variability out there.

So this is really about optimal and what’s possible.

And you have to ask, I can just say from personal experience

I suffer terribly from jet lag traveling

in certain directions, but not others.

Some people don’t have trouble with jet lag.

Many people will travel to a new location.

They feel great for the first day and night

and then they crash and they have trouble sleeping

or they travel back and they have a terrible time

getting back onto a normal schedule.

And some of this varies with age

and some of it varies with genetics.

And there is no simple pill or anything

that you can take to just get rid of jet lag.

It doesn’t work that way.

If it worked that way, I would tell you.

But there are some simple things that you can do.

I’m going to arm you with the knowledge of what jet lag is

and how it works.

And contrary to what many people out there say and believe

I know that understanding mechanism

affords you more flexibility.

Why understand mechanism as just opposed to me

just writing up a PDF and giving you a list of things to do?

Well, what happens when you can’t do those things

in exactly the way they’re written down?

When you understand mechanism,

you understand how to control the machine

that is your biological system, your nervous system.

So a little bit of understanding about mechanism

goes a really long way.

So that’s where we’re headed.

Let’s talk about what jet lag is.

Okay, well, I promised that I wouldn’t get too dark

with all the terrible things that can happen with jet lag

but I’m about to get dark.

There are quality peer-reviewed papers

showing that jet lag will shorten your life.

It will kill you earlier.

I guess it means you’ll die earlier.

It doesn’t actually kill you necessarily.

Although there are many cases where tourists

end up stepping in front of buses,

especially in countries where the cars and buses

drive on the opposite side of the street

that they’re used to,

who are jet lagged and lose their life that way.

Jet lag is a serious thing.

Should we have a family story about this?

When I was growing up,

I had a family member travel overseas for work

and take a sleeping pill.

I won’t name the sleeping pill,

though at the end I’m going to talk about sleeping pills

and had a case of total amnesia for a week.

That’s not entirely uncommon.

If you’ve ever been really jet lagged and fallen asleep,

doesn’t even have to be in the middle of the day,

woken up, you might not know where you are.

And that’s because time and space are really linked

and the brain wasn’t designed to be transported

four, five, six hours into a new time zone.

It just wasn’t.

Our brain and the biological mechanisms

that govern circadian timing

were designed to be shifted by a couple hours,

not necessarily six or nine or 12 hours.

So you can really mess yourself up.

I’ve had that experience.

I usually experienced it as fluctuations in mood.

I flew 12 hours out of phase to Abu Dhabi once

to give a talk at NYU Abu Dhabi, and it was a mess.

I actually was getting vertigo.

I wasn’t hallucinating, but I was really out of it.

And my mood was just all over the place.

It was very bizarre.

Jet lag, even if you don’t experience it

as mood shifts or amnesia, it can shorten your life.

Now, here’s what’s interesting.

Traveling westward on the globe is always easier

than traveling eastward, okay?

It’s interesting because the effects of jet lag

on longevity have shown that traveling east

takes more years off your life than traveling west.

Now, of course, traveling 30 minutes into a new time zone

or three hours, just one time zone over,

or two time zones over, rather,

is far less detrimental to your biology and psychology

than a eight-hour shift or a nine-hour shift.

Now, here’s what’s interesting.

When we think about the effects of jet lag on longevity,

or this idea that it can shorten our lives,

we have to ask ourselves, why?

Why is that?

And it turns out there’s a pretty simple explanation

for this.

We’ve talked before about the autonomic nervous system,

this set of neurons in our spinal cord and body and brain

that regulate our wakefulness and our sleepiness.

It turns out that human beings, and probably most species,

are better able to activate and stay alert

than they are to shut down their nervous system

and go to sleep on demand.

So if you really have to push

and you really have to stay awake, you can do it.

You can stay up later.

But falling asleep earlier is harder.

And that’s why traveling east

has a number of different features associated with it

that because you’re traveling east,

you’re trying to go to bed earlier.

You know, as a Californian, if I go to New York City,

I’ve got to get to bed three hours early

and wake up three hours earlier.

Much harder than coming back to California

and just staying up a few more hours.

And this probably has roots in evolutionary adaptation

where under conditions where we need to suddenly gather up

and go or forge for food or fight

or do any number of different things

that we can push ourselves through the release of adrenaline

and epinephrine to stay awake.

Whereas being able to slow down

and deliberately fall asleep is actually much harder to do.

So there’s an asymmetry to our autonomic nervous system

that plays out in the asymmetry of jet lag.

So if you want to read up on this,

because people have asked me about papers,

you can look, there’s a paper published by Davidson

and colleagues 2006 in Current Biology

that talks about the differences in lifespan

for frequent eastward versus westward versus no travel

and longevity and et cetera.

A number of different biological markers of longevity.

So going east is harder

because going to sleep earlier is harder

if you’re trying to do that on demand.

Many people have turned to melatonin

as a way to try and induce sleepiness.

I’m going to talk about melatonin at the end.

I’ve mentioned on previous podcasts,

a number of you have asked for the evidence

that melatonin is potentially detrimental

to some hormone systems.

Melatonin is a hormone and I’ll discuss that at the end,

in particular, the role of melatonin

in suppressing a hormone pathway

that involves luteinizing hormone,

testosterone in men and estrogen in females,

as well as a really interesting peptide

called kisspeptin, that’s a cool name.

All right, well, let’s think about travel and what happens.

Let’s say you’re not going eastward or westward,

but you’re going north or south.

So if you go from, for instance, Washington DC

to Santiago, Chile, or you go from Tel Aviv, Israel

to Cape Town, South Africa,

you’re just going north and south, right?

And not, you know, either direction.

You’re not really moving into a different time zone.

You’re not shifting.

So you will experience travel fatigue.

And it turns out that jet lag has two elements,

travel fatigue and time zone jet lag.

Time zone jet lag is simply the inability

of local sunlight and local darkness

to match to your internal rhythm,

this endogenous rhythm that you have.

So before we get too complicated

and too down in the weeds about this,

I want to just throw out a couple important things.

First of all, I mentioned this earlier,

but some people suffer from jet lag a lot,

other people, not so much.

Most people experience worse jet lag as they get older.

There are reasons for that,

because early in life, patterns of melatonin release

are very stable and flat and very high,

actually, in children.

It’s one of the reasons why they don’t undergo puberty.

Then it becomes cyclic during puberty,

meaning it comes on once every 24 hours

and turns off once every 24 hours.

It cycles, cyclic.

And then as we get older, the cycles get more disrupted

and we become more vulnerable

to even small changes in schedule, et cetera,

meal times, right?

So jet lag gets worse as we age.

In addition, there are other things that happen with age

that people start doing less exercise,

their digestion can get worse, et cetera.

So some of the effects of age

might not be direct effects of getting older,

but some of the things that are correlated with being older,

like people who are willing to have

a regular exercise regime can use that exercise regime

to shift their circadian clock.

And I have a good friend, his father’s in his 80s.

He’s still pushing out 25, 30 pushups each morning.

He’s on the Peloton or whatever it is,

doing a lot of cycling.

So some 80-year-olds are doing that, many are not.

Many 30-year-olds are not.

But if you have a regular exercise program,

that’s going to make it easier

to shift your circadian clock for sake of jet lag.

And it’s actually a knob you can turn

and you can leverage for shifting your clock.

Before we go any further,

I want to make changing your internal rhythm really easy,

or at least as easy and as simple

as one could possibly make it, I believe.

What I want to talk about is perhaps

one of the most important things to know

about your body and brain,

which is called your temperature minimum.

Most of you know your approximate weight.

Some of you even know your blood pressure.

Some of you might even know your body mass index.

Some of you might know other things about your biology

that have fancy names,

but everyone should know their temperature minimum.

Your temperature minimum doesn’t require

a thermometer to measure, although you could measure it.

Your temperature minimum is the point

in every 24-hour cycle when your temperature is lowest.

Now, how do you measure that without a thermometer?

It tends to fall 90 minutes to two hours

before your average waking time.

So I want to repeat that.

Your temperature minimum tends to fall 90 minutes

to two hours before your average waking time.

So let’s say you’re not traveling

and your typical wake-up time is 5.30 a.m.

Your temperature minimum is very likely 3.30 a.m. or 4.00 a.m.

If you want, if any of you want to,

you can measure your temperature minimum.

You can get a thermometer

and you can measure your temperature

every couple hours for 24 hours.

You can find your temperature minimum.

What you’re going to find is that you have a low point,

the temperature minimum,

and then your temperature will start to rise.

You’ll wake up about two hours later.

Then your temperature will continue to rise

into the afternoon.

It will peak, maybe a little trough.

Sometimes that happens.

And then it’ll start declining slowly

as you approach nighttime.

There are things that will disrupt that temperature pattern.

Saunas, cold baths, intense exercise, et cetera.

Meals tend to have a thermogenic effect

that increases temperature slightly, little blips,

but the overall cycle, 24-hour cycle of temperature

has this pattern.

And last time I talked about the seminal work

of Joe Takahashi and others who have shown

that temperature actually is the signal

by which this clock above the roof of your mouth

entrains or collectively pushes all the cells

and tissues of our body to be on the same schedule.

Temperature is the effector.

And once you hear that,

there should be an immediate, oh, of course,

because how else would you get

all these different diverse cell types

to follow one pattern, right?

A pancreatic cell does something very different

than a spleen cell or a neuron, right?

They’re all doing different things at different rates.

So the temperature signal can go out

and then each one of those can interpret

the temperature signal as one unified

and consistent theme of their environment.

So temperatures vary from person to person.

Some people are 98.6,

some people run a little colder, et cetera,

but you have a low point and you have a high point.

Know your temperature minimum.

How are you going to figure out this temperature minimum?

The temperature minimum can be determined

by taking the last three to five wake up times.

So let’s say you wake up 7 a.m., 8 a.m., 3 a.m.,

right, happens, take those, add them together,

average them by adding them up

and dividing by the number of days,

that’ll give you the average.

If you’re one of these people that wakes up at 3 a.m.

and then goes back to sleep and sleeps till 10,

your wake up time was 10 a.m.

If you use an alarm clock,

your wake up time is still when you get up, okay?

I know alarm clocks have been kind of demonized,

but in my world, being late and missing appointments

is also demonized, so I use an alarm clock.

Many people will wake up at exactly the same time each day.

There tends to be some variation for people.

Some people, it’s going to vary

depending on life circumstances,

but average that for three to seven days or so.

Take that wake up time.

You can then get an average

or sort of typical temperature minimum.

Okay, so now you know how to get your temperature minimum.

Your temperature minimum is your absolute reference point

for shifting your circadian clock.

Whether or not it’s for jet lag or shift work

or some other purpose.

Here’s the deal.

If you expose your eyes to bright light

in the four hours, maybe five or six,

but in the four hours after your temperature minimum,

your circadian clock will shift

so that you will tend to get up earlier

and go to sleep earlier in the subsequent days, okay?

It’s what’s called a phase advance,

if you’d like to read up on this further.

You advance your clock, okay?

However, if you view bright light

in the four to six hours before your temperature minimum,

you will tend to phase delay your clock.

You will tend to wake up later and go to sleep later.

Okay, I’m going to repeat this

because there’s so much confusion out there

and people talk about circadian time and all this.

Find your temperature minimum.

I tend to wake up at about 6 a.m.,

sometimes 6.30, sometimes 7.

It depends a lot on what I was doing the night before

as I’m guessing it does for you.

But that means that my temperature minimum

is probably somewhere right around 4.30 a.m.,

which means that if I wake up at 4.30 a.m.

and I were to view bright light at 4.35 a.m.,

I’m going to advance my clock.

I’m going to want to go to bed earlier the subsequent night

and wake up earlier the subsequent morning.

And as I shift my wake-up time,

my temperature minimum shifts too, right?

Because each time we shift our wake-up time,

our temperature minimum shifts,

assuming that wake-up time shifts more than 30 minutes

or an hour, okay?

If I were to view bright light in the four to six hours

before 4.30 a.m., guess what?

The next night I’m going to want to stay up later

and I’m going to want to wake up later

the subsequent morning.

Your temperature minimum is a reference point,

not a temperature reading.

Again, if you want to measure your temperature minimum

and figure out what it is, 98 point whatever,

or 96 point whatever, that’s fine.

You can do that, but that information won’t help you.

What you need to know is what time

your body temperature is lowest

and understand that in the four hours or so

just after that time,

viewing light will advance your clock

to make you want to get up earlier.

And the four hours before your temperature minimum,

viewing light will make you want to stay up later.

Now, some people might be saying,

well, I wake up early and I want to stay up late

and I’m sleepy all day and I’m a mess, or I feel fine.

Look, let’s talk about feeling fine.

It turns out the definition of insomnia

is when you’re experiencing excessive sleepiness

during the day.

Sleepiness and fatigue are different, okay?

So in the world of sleep medicine,

fatigue is a physical exhaustion.

Sleepiness is falling asleep,

like falling asleep at your desk

or falling asleep during lectures,

or there seems to be something special about my lectures

that makes people want to fall asleep.

So if this cures your insomnia, fantastic.

However, in all seriousness,

sleepiness during the daytime,

unless it’s around your temperature peak

and only lasts about 90 minutes or so,

is a sign of insomnia.

It’s a sign of lack of sleep.

So I want to be very, very clear

that if you know your temperature minimum,

you can shift your clock using light.

You can also shift your clock

by engaging in exercise in the four hours

after your temperature minimum

to wake up earlier on subsequent nights

or exercise before then to delay your clock, okay?

So now you can start to see and understand

the logic of this system.

And we’ll talk about why this works

and the underlying biology,

but understanding that temperature is the effector

and understanding that you have this low point

and that reflects your most sleepy point,

essentially, right before waking up,

and then temperature rises,

you can now start to shift that temperature

according to your travel needs.

Here’s one way in which you might do that.

Let’s say I am going to travel to Europe,

which is nine hours ahead, typically, from California.

I would want to determine my temperature minimum,

which for me is about 4.30 a.m., maybe 5 a.m.,

and I would want to start getting up at about 5.30 a.m.

and getting some bright light exposure,

presumably from artificial sources,

because the sunlight isn’t going to be out at that time,

maybe even exercising as well,

maybe even eating a meal at that time

if that’s in your practice.

You would want to start doing that

two or three days before travel,

because once you land in, or I land in Europe,

chances are just viewing the sunrise or sunset in Europe

is not going to allow me to shift my circadian clock.

Some people say, get sunlight in your eyes when you land,

but that’s not going to work,

because one of two things is likely to happen.

With a nine-hour shift like that,

either I’m going to view sunlight

at a time that corresponds to the circadian dead zone,

the time in which my circadian clock can’t be shifted,

or I’m going to end up viewing sunlight

at a time that corresponds to the four- to six-hour window

before my temperature minimum.

So it’s going to shift me

in exactly the opposite direction that I want to go.

So it can be very, very challenging

for people to adjust to jet lag.

So you need to ask, am I traveling east

or am I traveling west?

Am I trying to advance my clock or delay my clock?

Remember, viewing light, exercise, and eating

in the four to six hours before your temperature minimum

will delay your clock.

Eating, viewing sunlight, and exercising,

you don’t have to do all three,

but some combination of those in the four to six hours

after your temperature minimum will advance your clock.

And this is a powerful mechanism

by which you can shift your clock anywhere

from one to three hours per day, which is remarkable.

That means your temperature minimum

is going to shift out as much as three hours,

which can make it such that you can travel

all the way to Europe.

And as long as you’ve prepared for a day or so

by doing what I described back home,

and then doing it when you arrive,

you can potentially accomplish the entire shift

within anywhere from 24 to 36 hours.

And this is really important to emphasize

that once you arrive in your new location,

and here I’m talking about traveling eastward California

to Europe, once you arrive in your new location,

you have to keep track

of what your temperature minimum was back home

and how it’s being shifted during your trip.

Now, it’s much easier to do than you think.

One of the unfortunate consequences of the smartphone

is that you can’t do something goofy

like wearing two watches,

one watch that corresponds to the time back home

and another one that corresponds to the local time.

Typically it updates automatically based on Wi-Fi, et cetera.

But if you can keep track of the time back home,

then you can easily shift your clock going forward.

I’m hoping this would make sense.

I really want to emphasize

that you don’t have to be precise down to the minute.

Some of you may be asking,

well, what about you’ve got this temperature minimum

and if I view light one minute before it,

then I’m going to delay my clock

and one minute after it, I’m going to advance my clock.

It doesn’t quite work like that, okay?

But it’s very important to understand

that light is the primary way

in which we can shift our clock.

And now you should also be able to understand things

like the circadian dead zone from about 9.30, 10 a.m.

all the way until six hours before your temperature minimum,

you’re not going to shift your clock.

Nothing that you do in that time

in terms of light viewing behavior, feeding, et cetera,

is going to shift your clock.

And so a lot of people are landing in Europe,

getting sunlight in their eyes

and throwing their clock out of whack

or not shifting their clock at all.

This brings me to the other thing that’s highly recommended.

And I’ve mentioned this before,

but you want to eat on the local meal schedule.

If it’s in your practice to fast, fast, that’s fine.

But when you eat,

you want to eat within the local schedule for alertness.

Okay, that means if you arrive

and everyone’s eating breakfast

and you can’t stomach the idea of breakfast

in your new location because your appetite isn’t there,

that means the clock in your liver,

you have a clock in your liver,

biological clock has not caught up to the new time zone.

You can force yourself to eat if you like,

or you can skip that meal.

But what you don’t want to do

is stay on your home meal schedule,

waking up in the middle of the night and eating.

That is really going to throw things off

because a lot of the clocks in the periphery,

like from the liver, the peripheral body,

will send information back to the brain.

And then the brain is getting really conflicted signals.

So the temperature minimum is really your anchor point

for shifting your clock best.

I don’t know why this information

really hasn’t made it into the popular sphere quite so much.

There’s all sorts of stuff

about taking things like melatonin, using binaural beats,

a lot of kind of like more sophisticated, complicated,

and potentially problematic ways

of trying to shift the clock.

Let’s talk about melatonin.

But first I just want to pause

and shift gears a little bit

because I talked about traveling eastward,

but we haven’t talked about traveling westward.

So I want to do that now.

Let’s say you’re traveling from New York to California

or from Europe to California.

The challenge there tends to be

how can you stay up late enough?

Now, some people are able to do this

because as I mentioned earlier,

the autonomic nervous system is asymmetrically wired

such that it’s easier to stay up late later

than we would naturally want to

than it is to go to sleep earlier.

So let’s say you land and it’s 4 p.m.

and you’re just dying.

You’re in California, you came from Europe,

it’s 4 p.m. and you really, really want to go to sleep.

That’s where the use of things like caffeine, exercise,

and sunlight can shift you, right?

If it’s after your temperature peak,

then viewing sunlight around 6 p.m. or 8 p.m.

or artificial light, if there isn’t sunlight,

will help shift you later, right?

It’s going to delay your clock

and you’re going to be able to stay up later.

The worst thing you can do is take a nap

that was intended to last 20 minutes or an hour.

I do this routinely and then wake up four hours later

or you wake up and it’s midnight

and you can’t fall back asleep.

You really want to avoid doing that.

So provided it’s not excessive amounts,

stimulants like caffeine and coffee or tea

can really help you push past that afternoon barrier

and get you to sleep more like on the local schedule

and eating on the local schedule as well.

A number of people have asked about the use of melatonin

to induce sleepiness.

All right, well, let’s think about what melatonin is.

Melatonin is this hormone that’s released

from the pineal gland, which is this gland.

A couple notes about the pineal,

because I’ve been getting a lot of questions about this.

I’m probably going to draw some fire for this,

but I’d be happy to have a thoughtful, considerate debate

with some peer-reviewed papers in front of us.

The pineal does make this hallucinogenic molecule

they call DMT, but in such minuscule amounts

that it is not responsible for the hallucinations

you see in sleep and dreaming.

Sorry, folks.

It’s also not responsible for the hallucinations

you might see through other approaches to DMT.

It’s just not, that’s not where the DMT comes from.

It’s infinitesimally small amounts.

There are a lot of kind of wacky claims out there

about calcification of the pineal and fluoride

and this kind of thing.

Look, the pineal sits in an area of the brain

near the fourth ventricle

where the skull is not terribly far away,

although there’s some overlying neural tissue.

And with age, there’s some aggregation

of some of the meninges and other things around there

that stick to the skull.

Young brains don’t look like old brains,

but there’s no calcification of the pineal, all right?

So you can forget about calcification

of the pineal as a problem.

I don’t know where that whole thing got started,

but that’s not an issue.

Your pineal will churn out melatonin your whole life.

Melatonin induces sleepiness.

Melatonin during development is also responsible

for timing the secretion of certain hormones

that are vitally important for puberty.

Does melatonin control the onset of puberty?

Not directly, but indirectly.

Melatonin inhibits something

called gonadotropin-releasing hormone,

which is a hormone that’s released from your hypothalamus,

also roughly above the roof of your mouth and your brain.

Gonadotropin-releasing hormone is really interesting

because it stimulates the release of another hormone

called luteinizing hormone,

which in females causes estrogen

to be released within the ovaries.

It’s involved in reproductive cycles,

and in males, stimulates testosterone

from the sertoli cells of the testes.

Melatonin is inhibitory to GNRH,

gonadotropin-releasing hormone,

and therefore is inhibitory to LH, luteinizing hormone,

and therefore is inhibitory to testosterone and estrogen.

There’s just no two ways about it.

There is immense amount of data on the fact

that high levels of melatonin in seasonally breeding animals

takes the ovaries from nice and robust ovaries

that are capable of deploying eggs and this kind of thing,

and literally shrinking them

and making these animals infertile.

These are very high levels of melatonin

in seasonal breeders in winter.

Melatonin in males of seasonal breeders

takes the testes and shrinks them.

Long ago, when I was at UC Berkeley as a master student,

I was working on neuroendocrinology,

and we were working on this hamster species

of seasonal breeders,

and basically when days are long, which inhibits melatonin,

these little Siberian hamsters, as they’re called,

have testes about the size of sort of typical table grapes,

although that’s a weird way to put it.

When days get shorter and the melatonin signal gets longer,

because light inhibits melatonin,

days get shorter, melatonin gets longer,

those same hamsters would have testes

that would involute to the size of about a grain of rice.

Now, this does not happen in humans in short days,

but nonetheless, the melatonin signal

really does have a ton of effects on the hormone system.

Now, does that mean that if you’ve been taking melatonin,

you’ve really screwed up your hormones?

Not necessarily.

Does it mean if a kid has been taking melatonin,

that’s really screwing up their puberty?

Not necessarily, and here’s why.

Melatonin operates on a concentration level,

so in a child that’s very, very small,

that has high levels of melatonin,

it actually can inhibit GNRH, LH, testosterone, or estrogen,

depending on the sex of the child,

but as that child grows through other mechanisms,

like growth hormone release, et cetera,

that same amount of melatonin released from the pineal

is now diluted over a much larger body,

so the concentration actually goes way, way down, okay?

But here’s the problem with supplementing melatonin.

As I mentioned in the previous episode,

concentrations of melatonin in many commercial supplements

have been shown to be anywhere from 85% to 400%

of what’s listed on the bottle,

so when you take melatonin, or a child takes melatonin,

oftentimes they are taking

supraphysiological levels of melatonin,

which, at least by my read and the literature,

says that it could have dramatic effects

on timing and course of things like puberty.

So it’s not so much that the journals have come out saying,

oh, taking that melatonin inhibits puberty,

it’s that no single study has been done

with the supraphysiological levels of melatonin

that are present in a lot of these supplements

in developing children.

So melatonin is used widely for inducing sleepiness

when you want to fall asleep

in the new location that you’ve arrived, right?

You can’t fall asleep,

you take melatonin, it helps you fall asleep.

It does not help you stay asleep.

In addition to that,

melatonin has been kind of touted

as the best way to shift your circadian clock.

I’m happy to go on record saying,

look, if you need melatonin and you can work with a doctor

or somebody who really understands circadian

and sleep biology, go for it if that’s your thing,

but I, as always on this podcast and elsewhere,

I have a bias toward behavioral things

that you can titrate and control,

like exposure to light, exercise, temperature, et cetera,

that have much bigger margins for safety

and certainly don’t have these other endocrine effects

that we’ve been thinking about and talking about.

So if you want to take melatonin in the afternoon

in order to fall asleep or in the evening,

be my guest, that’s up to you.

Again, you’re responsible for your health, not me.

But for many people,

melatonin is not going to be the best solution.

The best solution is going to be to use light

and temperature and exercise

on either side of the temperature minimum

to shift your clock both before your trip

and when you land in your new location

and your clock starts to shift.

Okay, so now you know my opinions about melatonin.

Feel free to filter them through your own opinions

and experiences with melatonin.

And now you also understand what your temperature minimum is

and how it represents an important landmark,

either side of which you can use light temperature

and exercise to shift your clock.

Just to remind you a little bit about temperature,

if you want to shift your clock,

typically you would do that by,

you could take a hot shower

and then that will have a cooling effect

after the hot shower.

And if you were to get into a cold shower or an ice bath,

if you have access to one,

afterward there’s going to be a thermogenic effect

of your body increasing temperature.

And if you just think about your natural rhythm back home

when everything’s stable,

you have a nadir, a low point in,

which is your temperature minimum,

and then you have a peak.

And you think about when you’re doing this hot

or cold shower in that rhythm,

now you should be able to understand

how you’re shifting your rhythm.

That temperature rhythm is the one that’s going to move.

Give you an example.

If I were to wake up in the morning

and let’s say I wake up at 6 a.m.,

my temperature I know is rising,

I’ve passed my temperature minimum.

If I were to get into a hot shower

that would then lower my body temperature when I got out,

that is not normally what’s happening

first thing in the morning.

And therefore my clock would very likely get phase delayed.

Right, it’s going to delay the increase in temperature.

Whereas if I got into a cold shower,

something I don’t personally like to do,

but I’ve done from time to time or an ice bath,

that’s going to then have a rebound increase

in body temperature and is going to phase advance my clock.

That peak in the afternoon

is going to come about an hour earlier.

I’m going to want to go to bed earlier, later that night.

So you can start to play these games

with timing and hot and cold,

with meals, whether or not you eat or you don’t eat,

and with light exposure,

whether or not you view light or you don’t view light.

So now you can start to see why understanding

the core mechanics of a system

can really give you the most flexibility

because I could spend the next 25 years of my life

answering every question

about every nuanced pattern of travel.

Well, we’re going to Sydney, then we’re going there.

What should I do?

But that’s on you.

You need to figure out your temperature minimum

and your temperature peak, if you like,

and then use these parameters to, it gives you flexibility.

And that really underscores the most important thing

is that when you understand mechanism,

it’s not about being neurotically attached

to a specific protocol, it’s the opposite.

It gives you power to not be neurotically attached

to a specific protocol.

It can give you great confidence and flexibility

in being able to shift your body rhythms

however you want, and when things get out of whack,

you can tuck them right back into place.

One thing that’s common is that people

need to do a quick trip.

It’s not always that you’re going to go to,

you know, on vacation for two weeks or, you know,

work someplace else for weeks on end.

If your trip is 48 hours or less,

stay on your home schedule.

This can be tough and it may require scheduling meetings

according to your home schedule.

But if you can somehow manage that,

the best thing to do would be to stay on your home schedule.

Your clock is not going to shift more than a couple hours,

even if you do everything correctly in one day, okay?

So if I were to travel, say, to Europe,

I’ve actually done this.

I did a 24-hour trip to Basel, Switzerland,

gave a talk and came back.

People thought I was crazy,

but I had a little bit of travel fatigue

because remember there’s fatigue

from the actual travel experience.

The novelty of it, the air is never great on the planes.

This was even true before there were mask requirements

and things like that.

There’s the travel fatigue,

but you don’t throw your clock off.

If you stay 48 hours,

then you start to shift a little bit.

72, that’s when you start running into trouble.

The transit time is also important,

but I would say if it’s three days or less,

stay on your home schedule as much as you can.

And because sunlight isn’t under your control,

unless there’s something about you I don’t know,

that’s when traveling with some sort of bright light,

like the light pad that I have down there

that I showed earlier.

For those of you listening just on audio,

it’s just, it looks like an 8 1⁄2 by 11 pad.

It’s actually not designed for wake up.

It’s actually designed, it’s a drawing pad,

and you can, and it emits about 1,000 lux of light.

And so if you want to travel with something like that,

you can use that in your hotel room

to wake up when you like.

Some people will use nightshades,

you know, not the nightshades that you eat

or that some people say you’re not supposed to eat,

I don’t know anything about that,

but the eye covers to keep light out.

Those can be very useful on planes and in hotels and so on.

So you can use light and dark,

and you can travel with your light and dark devices

so that you can stay on your home schedule

and get most of your light

when it would be your normal wake up time back home.

And what’s kind of nice is if you know

when your circadian dead zone is back home,

which is generally for most people

around 10 a.m. to about 3 p.m.,

so basically the rising phase of your temperature,

then you can also feel free to be outside

without having to wear sunglasses

or you don’t have to worry about light exposure.

But if you know that window

before your temperature minimum,

that four to six hour window,

that’s the time when if you’re viewing a lot of light

in your new location,

you are going to shift your clock pretty considerably.

And then you can come back home and have a terrible time.

At the end of graduate school, I went to Australia,

a remarkable country, incredible people,

incredible wildlife, an amazing time.

I came back and it was the first time in my life

where I couldn’t sleep on a regular schedule.

I was sleeping in like hour long increments

throughout the day.

It was a nightmare.

And it took me weeks to get back on target.

And the way I was able to do that

was exercising consistently at the same time,

every 24 hours,

turning my home into essentially a cave at night,

even covering up the windows,

and then getting as much bright light in my eyes

as I possibly could during the day,

no sunglasses, et cetera.

So it can take some real work

if your clock gets thrown out of whack.

There’s a phenomenon called ICU psychosis

where people that are in the intensive care unit

in hospitals actually lose their mind.

They become psychotic, hallucinations, et cetera.

And it’s because of altered circadian cycles.

We know this because they’re exposed to these lights

and these sounds, people coming in and checking on them.

They leave the hospital,

or in some cases there’ve been experiments

where people are placed near a window

where they get some natural light

and these psychotic symptoms disappear,

presuming there weren’t psychotic symptoms beforehand

before they entered the hospital.

So it’s pretty dramatic what light can do

to the psyche and to the body.

So let’s talk a little bit

about a different form of jet lag

that requires no planes, no trains, no automobiles,

and that’s shift work.

Shift work is becoming increasingly common.

Many of us are shift working even though we don’t have to.

We’re doing work in the middle of the night.

We are working on our computers at odd hours,

sleeping during the day.

A lot of people who are under shelter in place type stuff

are doing more of this.

Kids with the drifting school schedules.

Here’s the deal with shift work.

If there’s one rule of thumb for shift work,

it’s that if at all possible,

you want to stay on the same schedule for at least 14 days,

including weekends.

Now that should immediately cue the non-shift workers

to the importance of not getting too far off track

on the weekend, even if you’re not a shift worker.

So sleeping in on Sunday is not a good idea.

The most important thing about shift work

is to stay consistent with your schedule.

Now I had a conversation on Instagram Live

with Samer Hattar,

who’s a neuroscientist

at the National Institutes of Mental Health.

He’s actually the head of the chronobiology unit there.

And he was really emphasizing this point

because shift work,

where people are doing the so-called swing shift,

where they’re working four days on one shift

and four days on another,

is extremely detrimental to a number of health parameters.

It gets the cortisol release from the adrenals

really out of whack.

And there are these cortisol spikes

at various hours of the day.

It messes up learning.

It really disrupts the dopamine system and wellbeing.

It is a serious, serious problem.

So if you can negotiate with your employer

to stay on the same shift for two weeks at a time,

that’s going to be immensely beneficial

and will help you offset

a lot of the negative effects of shift work.

Now, I don’t presume that all of you

are going to be able to do that.

Some of you just don’t have that level of control.

And of course, I want to acknowledge

that shift workers are essential, right?

Of course, first responders, firefighters,

police officers, paramedics, et cetera,

but also pilots, night nurses,

people working on the hospital wards,

people picking up trash.

These night shifts are critical

to our functioning as a society,

as I’m sure all of you can appreciate.

If you’re going to work a shift

where let’s say you start at 4 p.m.

and you end at 2 a.m., excuse me,

then there’s some important questions that arise.

For instance, should you see light during your shift?

Well, this is a matter of personal choice,

but ideally you want to view as much light as possible

and as safely possible when you need to be alert.

So that would mean from 4 p.m. to 2 a.m.

And then you would want to sleep.

So using light as a correlate of alertness

and using darkness as a correlate of sleepiness,

what this means is see as much light as you safely can

during the phase of your day when you want to be awake.

So it’s the same thing I said way back

at the beginning of this podcast episode.

And see as little light as safely possible

and allows you to function during the time

when you want to be asleep.

So if you’re finishing out that 2 a.m. shift,

that’s when you would want to avoid bright light exposure.

You’d want to go home.

You’d really want to avoid watching TV if possible.

If you need that in order to fall asleep,

that would be a case where something

like dimming the screen plus blue blockers,

if that’s in your practice,

or you want to do that would be helpful

and then going to sleep.

And then you’ll probably wake up late in the afternoon

or early afternoon.

Some of you might say,

wait, Huberman, I thought you don’t like blue blockers.

I never said I don’t like blue blockers.

I don’t like people wearing blue blockers

at the time of day when they want to be alert.

And I don’t like people asserting

that blue blockers can prevent circadian shifts

simply because people are wearing them.

The brightness of light is what’s important.

It’s not about the blue.

So if you want to wear them, wear them,

or just dim the lights or turn the lights off.

So let’s say you go to sleep at,

you get home after this 4 p.m. to 2 a.m. shift.

You maybe eat something.

You go to sleep and you wake up and it’s noon or 1 p.m.

Should you get light in your eyes?

Well, your first assumption based

on what I’ve said previously might be

that you’re in the circadian dead zone,

that you can’t because it’s noon or 1 p.m.

But you’re not in the circadian dead zone

because you’re somebody who goes to sleep

early in the morning at 2 a.m.

So it’s not like the circadian dead zone

is a strict time of day.

It’s an internal biological clock.

So what do you need to know?

You guessed it.

You need to know your temperature minimum.

You need to know whether or not

your temperature is increasing or decreasing.

And now we can make this whole thing even simpler

and just say, if your temperature is decreasing,

avoid light.

If your temperature is increasing, get light.

It’s that simple.

Okay, if your temperature is decreasing, avoid light.

If your temperature is increasing, get light.

The shift worker who works from 4 p.m. until 2 a.m.

has a temperature rhythm that’s very different than mine

where I wake up around 6 a.m., 5 a.m.

and I go to sleep around 11 p.m., okay?

We both have a 24-hour-ish circadian cycle

except mine is more aligned to the rise

and setting of the sun and theirs is not, right?

So you have to know your internal temperature rhythm

and know you don’t have to walk around with a thermometer

wherever taking your temperature.

Although it’d be great if some of the devices

that are out there, you know,

people are counting their steps.

I think it’d be great

if people had a circadian body temperature measurement.

I’m not involved in any of this device development,

but I think it’s a real call to arms, pun intended,

to have a wristband that would measure temperature

and would tell you your temperature minimum

when you travel or whatnot.

I don’t know, maybe some of these devices already do that,

but if they don’t, they should.

It’s absolutely absurd to me

why we wouldn’t have this simple measurement.

Very easy to get that kind of information.

You don’t even need the exact temperature read.

All you need to know is the high and low point.

Let’s say you’re a shift worker who really is nocturnal.

You’re flipped.

Well, you want to stay on that nocturnal schedule.

Now, that can be very hard on families

and social life of all kinds,

but the person who is working, say, from 8 p.m.,

like sundown to sunrise, this raises a question.

Should they be looking at the sunrise

and should they be watching the sunset,

waking up with the sunset, going to sleep with the sunrise?

You think, well, is that light going to throw them off?

Probably not.

It’s just actually going to invert

what sunrise and sunset are.

When they’re waking up in the morning,

if they get some sunlight in their eyes,

they look at the sun and get some bright light

from devices or overhead lights in their apartment or home,

well, that’s going to tend to wake them up

if it’s in the evening, right?

So it’s, I don’t know if I stated that clearly,

but if in the evening the sun is setting

and they’re looking at that setting sun,

that is the morning sun for that person

and it will wake them up for their night shift.

So temperature rising.

Then toward morning, what’s happening?

Okay, well, they’re closing out their work shift.

You’re going home.

The sun is rising.

Do you look at the rising sun?

Well, based on what you now know,

your eyes are very sensitive

to resetting of circadian clocks.

What will it do at that time?

If this were a classroom,

I would either cold call on somebody

or I’d wait for the person in the audience.

That would inevitably exist.

So temperature for that person,

they’ve been up for a while.

Temperature is falling, not rising.

For me, it would be rising,

but because I’m not diurnal, I’m awake during the day.

For that person, the temperature is falling

and so they view light while temperature is falling.

What’s it going to do?

It’s going to phase delay them.

It’s going to make it harder for them

to get to sleep the following night.

So you would say that person should watch the setting sun

to help them wake up

because they’re going to work the night shift,

but you probably have sunglasses on

or avoid viewing bright light before they go to sleep.

So it’s the same thing.

They’re just on an inverted,

as a typical person who’s diurnal,

but they’re on an inverted schedule.

And so I’m really trying hard here

to make this all really clear.

There are kind of two patterns of requests in the world

I’m noticing as I’ve kind of ventured

into this landscape of social media and podcasts.

There are people who want to know every detail,

want to quantify everything

because they want to get exactly right.

These are like the graduate students

and students that don’t want to make a mistake.

And to quote my graduate advisor,

provided the mistakes are not dangerous,

certainly not lethal,

you kind of want to make a few little mistakes

so that you can adjust, right?

You don’t want to endanger yourself,

but it’s actually, you’re not going to get things perfect.

That’s called learning.

Learning is when you realize,

oh, I viewed some this time and then I stayed up

and it really messed me up.

I’ll never do that again.

The other category of people seem to want

the one size fits all kind of like,

give me this pill or give me this protocol.

And those things generally work,

but they don’t afford people flexibility.

And if there’s anything like that,

it’s this temperature minimum thing

that I’ve been just hammering on again

and again and again today,

because it’s something that you own

and that you can really use as a key landmark

for shifting your clock.

I suppose there’s a third category,

which is people who accept that biological systems

are actually much more forgiving

than the way they’re sometimes described.

And I’m going to use this as an opportunity

to editorialize a little bit.

You know, there’s so much made of sleep debt.

Look, there isn’t an IRS equivalent for sleep.

They’re not going to come around

and try and collect all the sleep

that you didn’t get.

No one really knows what the consequences

are going to be for you and for me

and for the next person for the sleep you didn’t get.

You can’t really recover the sleep you missed out on,

but you also don’t want to get

neurotically attached to a schedule

because there’s this thing called sleep anxiety,

and then people have trouble falling asleep

and staying asleep.

So I want to spend a moment on that

and go back to a theme that I’ve said many times before,

because these tools work,

what I called NSDR, non-sleep depressed.

So this would be hypnosis.

I give you the link, but I’ll say it again, for clinically tested,

research tested, free hypnosis for anxiety,

but also for sleep.

Those are very beneficial people.

NSDR protocols, non-sleep depressed protocols

for things like yoga nidra.

I provide some links to those in the caption for episode two.

These things really work.

Last night I woke up, I went to bed about 1030.

I woke up at three in the morning.

I knew I wasn’t feeling rested.

I did a NSDR protocol.

I fell back asleep.

I woke up at 630, okay?

You need to teach your brain and your nervous system

how to turn off your thoughts and go to sleep.

And ideally you do that without medication,

unless there’s a real need,

you do that through these behavioral protocols.

They work because they involve using the body

to shift the mind,

not trying to just turn off your thoughts

in the middle of the night.

Now there are periods of life where things are stressful

and people are concerned

and you will have some struggle getting and staying asleep.

And that really has to do more with anxiety,

which NSDR protocols also can help with.

As I always say, do them in the middle of the night

if you wake up and you want to go back to sleep,

do in the middle of the day

to teach your nervous system how to calm down

or do them first thing in the morning

if you didn’t feel you got enough sleep.

In other words, do them whenever you have an opportunity

to do them because they really can help you learn

how to turn on the parasympathetic

slash calming arm of your autonomic nervous system.

There’s no other way that I’m aware of

to teach your system to slow down

and turn off your thoughts and go back to sleep.

But these are powerful protocols

and there’s a lot of research now

to support the fact that they can really help.

Meditation would be another example.

Meditation of certain kinds of meditation

involve focus and alertness.

Those are slightly different than meditations

that involve lack of focus and attention

to say internal states.

I’m going to pause there

and then I want to talk about kids and the elderly.

In other words, how do we control sleep

and circadian rhythms and wakefulness

in babies, adolescents, teens, and aged folks?

All right, before we talk about sleep and kids,

I want to tell a little story.

It’s not a joke.

Many of you will be relieved that I’m not going to try

and tell another joke this episode,

which is the relationship between light,

skin and pellage color, dopamine and reproduction, mating.

So many seasonally breeding animals,

Siberian hamsters, which I mentioned earlier,

rabbits, fox, other animals change their color

of their coat.

In the winter, they tend to be a lighter color.

Sometimes pure white,

sometimes with flecks of black or brown.

And in the summer, their pellage changes to a color

of brown or red, some other vastly different color.

That shift is controlled by light and by melatonin.

This has an interesting correlate in humans.

So humans obviously have different skin tones,

just genetically, because of the amount of melanin

in one’s skin, depending on genetic background.

But of course, sunlight will increase the amount of melanin

in the skin regardless, right?

This is sun tan, sunburn, et cetera, bronzing, whatever.

The whole system is wired so that shifts in skin color

and shifts in these cells within the eye and melatonin

are actually very closely linked.

So here’s the story.

Many years ago, meaning about 10 years ago, 15 years ago,

let’s see, it was 20 years ago, forgive me,

a guy named Iggy Provencio,

who was running his own lab at Uniformed Armed Services.

This is a standard biological laboratory,

discovered that there was an opsin in the eye,

in the cells of the eye that connect

to the rest of the brain called melanopsin.

Melanopsin, as many of you now know, is the opsin.

It’s like a pigment.

It absorbs light.

It is the opsin that converts light into electrical signals

that then set the circadian clock.

Iggy discovered melanopsin because it was similar in form

to what was in frog melanophores.

It was actually in the skin of frogs

that allowed those frogs to go from pale white

when it was dark for most of the 24-hour cycle

to pigmented, green or brown for a frog.

So there’s this relationship between the cells in our eye

and the pigment cells of our skin.

And we also know that in long days, there’s more breeding.

How does that work?

Well, that’s actually from dopamine

triggering increases in testosterone mainly in males

and estrogen mainly in females,

although of course there’s testosterone and estrogen

in both sexes.

So we have this kind of pathway where it’s light,

increases in melanin, dopamine and reproduction

on the one hand, and lack of light, melatonin decreases

in the darkness of skin, less melanin in the skin,

or in the case of an animal with fur,

white fur and no reproduction on the other hand.

And humans don’t actually shift their breeding patterns

tremendously from long days and short days,

although there are some data that there’s some shifts.

We also don’t radically change our skin color

depending on how much sunlight exposure we have.

But the simple way to put this is when days are long,

there’s a lot more dopamine and we feel really good.

And there’s a lot more breeding and breeding like behavior.

When days are short, there’s a lot less dopamine

and a lot less breeding behavior

because these pathways are very highly conserved.

Now, what’s interesting is that as we’ve moved

into a modern society where much of our waking days

we are looking at screens, which is fine

because we’re getting a lot of light that way,

although not as much as sunlight.

But also at night, we’re getting a lot of light

from screens.

What’s happened is all these pathways,

melanin in the skin, turnover of skin cells, dopamine,

all of this stuff has become completely disrupted.

Now that’s not to say that we should go back to a time

in which we didn’t use artificial lights,

but I think the important thing to realize

is that feeling good with getting a lot of light,

the relationship to dopamine and melanin in the skin

and the good feelings of getting light also on our skin,

provided you’re not getting burned

or you’re not getting excessive UV exposure,

those are not just coincidences.

Those are hardwired biological mechanisms

that exist in everybody, regardless of how light or dark

your skin is to begin with.

There’s another point which is important,

which is that the dopamine system,

which is this feel-good molecule,

is very closely related to the testosterone and estrogen

and reproductive cycles.

Remember, melatonin inhibits

gonadotropin-releasing hormone, luteinizing hormone,

and the production of these hormones.

And melatonin is the effector.

It is the hormone of darkness.

So I just threw a lot of biology at you,

and I’m not saying you’re like a Siberian hamster,

at least not in ways that I’m aware of.

I’m not saying that your pellage color is going to change.

Actually, the reason people go gray

is because when you’re really stressed, did you know this?

When you’re really stressed,

there’s an increase in the nerve fibers

that release adrenaline to the hair follicle,

and that activates peroxide groups in the hair follicle

that cause the hair to actually go gray or white.

So actually, stress does make your hair gray or white.

Aging does it too.

So that was a brief aside,

but for those of you that are interested

in the relationship between light and skin tone

and all that kind of stuff,

I thought you might find it interesting

that these cells in your eye

are a lot like these skin cells in frogs or in animals

that shift their entire color

and sometimes metamorphosize.

You know, there are some species

that literally change shape in the reproductive organs.

In fact, if that wasn’t weird enough,

when I was in graduate school at Berkeley,

there was another graduate student

studying a species of hermaphroditic mole,

right, those little things that dig,

hermaphrodite mole that would change

from having ovaries to testes and back again,

depending on daylight.

Super cool, super different and wild biological mechanism.

If you’re wondering how those animals reproduce,

they actually adjust the numbers of males and females

depending on the density of males and females.

So if there are too many males,

some of the males turn their testes into ovaries

and if there are too many females,

they turn their ovaries into testes.

They actually are true hermaphroditic animals

as opposed to pseudo hermaphroditic animals.

Okay, let’s get back on track.

Let’s talk about the animal that most of you care about,

which is the human animal.

New parents and babies.

All right, as I mentioned earlier,

melatonin is not cyclic, it’s not cycling in babies.

It’s more phasic, it’s being released

at a kind of a constant level.

And babies tend to be smaller than adults, they are.

And so those concentrations of melatonin are very high.

As a baby grows, those concentrations per unit volume

are going to go down.

Babies are not born with a typical sleep-wake cycle.

And now all the parents saying,

tell me something I didn’t know.

They also have, and I really want to emphasize this,

they also have much more sensitive optics of the eye.

So a number of people have asked me,

should I be exposing my baby to sunlight?

You don’t want to avoid sunlight,

but their eyes are very sensitive.

The optics of their eyes aren’t quite developed,

so much so that when you look at a newborn baby

and they look a little glassy-eyed

and they’re kind of looking through you

or even a young child, a lot of people think

that they’re seeing you the way that you’re seeing them.

Hate to break it to you, but if you ever can just Google

visual image of a one-month-old,

the optics of their eyes are so poor

that you’re a cloudy image.

They’re not seeing your fine detail.

As the optics get better,

then they will see you with more and more clarity.

But a lot of that is clearing of the lens

and some of the other aqueous features of the newborn eye.

They don’t see very well.

But they also don’t have such great ways

of adjusting to bright light.

And so babies have a natural aversion to bright light.

So you really want to avoid trying to use sunlight

or really bright light in the same way

that you would for an adult on a young baby or child.

As children get older, however,

melatonin does start to become slightly more cyclic,

slightly more cycled,

and their body temperature rhythms

also start to fall into a more regular,

not quite 24-hour rhythm.

They’re more of these ultradian rhythms.

So in an episode,

I think it was one or two of the podcast, or maybe both,

we talked about these 90-minute so-called ultradian rhythms

where every 90 minutes,

babies are going through a cycle of body temperature

and some other hormonal features.

I mean, so much is changing in their system.

So what to do if a child isn’t sleeping?

You can use phases of darkness and phases of light,

but they’re going to have to be shortened

in order to try and encourage sleep

when you want the child to sleep.

It’s not that they’re just not going to fall

into an adult-like regime of a temperature minimum

and a temperature maximum.

Their temperature minimums and maximums

are fluctuating much more quickly,

and it varies tremendously.

Actually, there’s an interesting literature

of whether or not they have siblings,

whether or not they’re twins,

whether or not they’re in a nursery environment,

whether or not they’re alone.

Hopefully the baby’s not alone, but you know what I mean,

that they’re sleeping alone in a room

while you’re in the other room.

There are a couple of things that seem to help,

which is getting the overall environment

into a 24-hour schedule.

So having the room slightly colder,

obviously you want babies to be nice and cozy,

slightly colder when you would like them to be asleep,

slightly warmer for the times

you would like them to be awake.

Babies tend to run pretty hot anyway.

And obviously you want to be very careful

about avoiding all extremes of temperature, cold or hot.

So if they’re going through these 90-minute cycles,

you’re going to have to adjust

to those 90-minute cycles as well.

So then people say,

well, that’s not going to help me at all

because how do I deal with the fact

that I need to be up every 90 minutes at night?

There are a couple tools that can be helpful.

The first one is going to be to try

and understand the relationship

between calm and deep sleep.

So the autonomic nervous system

can put us into states of panic

where that’s kind of seesaw of autonomic alertness

goes all the way to panic,

or it can be alertness or it can be alert and calm, right?

So there’s a range there, it’s a continuum.

Can also be that you’re in deep sleep,

so the other end of the seesaw is way up,

or you’re in light sleep, or you’re kind of sleepy,

or you’re just feeling kind of relaxed.

Perhaps the most important thing

if you’re having to map to a baby’s schedule

in order to make sure that they’re getting changings

and nursing, et cetera, at the appropriate times

is to try and maintain, if you can’t sleep,

or you can’t sleep continuously,

to try and maintain your autonomic nervous system

in a place where you’re not going

into heightened states of alertness

when you would ideally be sleeping.

Now, I realize that this could be translated

to try and stay calm while you’re sleep deprived,

which is very hard for people to do,

but this is where the non-sleep deep rest protocols

surface again, and can potentially be very beneficial

for people to be able to recover, not necessarily sleep,

but for them to maintain a certain amount

of autonomic regulation.

So what would this look like?

This would look like the baby goes down,

maybe it’s only going to go down for 45 minutes.

If you can capture sleep,

capture sleep, there are some data showing

what’s called polyphasic sleep.

If you can sleep in 45-minute increments or batches,

even if it’s spread throughout the day

with periods of wakefulness in between,

as miserable as that sound,

there are actually some adults

that have deliberately employed that

who don’t have children for sake of work productivity,

and it does tend to reduce

the total overall amount of sleep that you need.

It is a very hard schedule for most people to maintain,

but if you have a baby,

the baby may be throwing you

into that kind of schedule anyway.

So if you can get 45 minutes sleep while they sleep, great.

If you can get another 45 minutes after waking

and then they go back down to sleep, great.

So as many phases of sleep as you can get,

but if you can’t sleep,

the data on non-sleep deep rest type protocols

does show that at least from a neurochemical level,

want to be clear what that means,

reset of things like dopamine levels in the basal ganglia

measured by things like positron emission tomography,

et cetera, those things tend to reset themselves pretty well

if you can access these deep rest states.

So that means not being alert

throughout the entire time that the baby is sleeping,

trying to sort of mirror the baby’s sleep cycle,

which can be brutal for certain people,

and especially if you’re trying to prepare meals

and do all these things.

So I do recognize that there are a lot of constraints

on parenting, not just mapping on your baby’s sleep schedule.

As children approach ages one, two, three, four,

that’s when certainly the optics of the eyes have improved,

but you don’t want to damage the eyes, of course,

with very bright light.

They are much more sensitive

even until they’re kind of 10, 11 years old.

And we’ll talk about vision in children in a moment,

but trying to get longer and longer batches of sleep

through, hopefully not through the use

of administering melatonin to the kids,

because that’s what I talked about before,

why that could potentially be detrimental.

Talk about that with your doctor,

but more so trying to get longer blocks of sleep

that map onto these ultradian cycles.

So it would be better off to get a three hour,

like two 90 minute cycles,

then to a four hour batch of sleep

because waking up in the middle of those ultradian cycles

can just be brutal for parent and kid.

So if one can’t get a full six or 10,

or some kids should even be sleeping 12 hours

when they’re growing quickly,

trying to get batches of sleep,

even if they’re fractured throughout the 24 hour cycle

that are matched more to these 90 minute cycles,

meaning maybe one ultradian cycle of 90 minutes

or two back-to-back or three back-to-back-to-back,

that’s going to be better than waking up

in the middle of an ultradian cycle.

It’s just going to set any number of other things

in a better direction than were you to try to say,

just enforce or force a full eight or 10 hours of sleep.

That’s at least what the literature shows.

Some kids sleep great through the night,

starting at a very young age, others don’t.

I typically hear from people who are struggling tremendously.

They’re losing their mind, understandably,

because they’re not sleeping, their kid’s not sleeping,

or their kid is sleeping for such brief periods.

So in other words, trying to access deep calm

if you can’t sleep,

trying to access sleep if you can sleep,

even if it’s fractured.

And then you say, well, what about all the sunlight viewing

and the exercise stuff?

When sleep is really, really dismantled,

meaning it’s happening in various times of day or night,

that’s especially, at those times,

it’s going to be especially important for the parent

to get morning and evening sunlight

because your circadian clock is going into a tailspin

and it basically wants to anchor to something.

So you want to give it two anchors,

morning and evening light, okay?

So this is rather different

than what I described for shift work.

This is when things are really chaotic

and you’re just not able to sleep.

Similar circumstances can arise

if you’re taking care of a very sick loved one,

you’re up all night, try and stay calm using NSDR protocols.

I know it’s harder to do than to say,

but those protocols are there, they’re free.

There’s research to support them.

Try and get sleep whenever you can,

but also try to get morning sunlight

and evening sunlight in your eyes if you can.

And if you can’t get that, use artificial light, okay?

What about later life?

So kids now, adolescents, teens,

it is true that teens have a tendency to wake up later

and go to sleep later,

in part just because they’re sleeping a lot more.

They’re churning out gonadotropin-releasing hormone

and luteinizing hormone.

Their whole bodies are changing.

I don’t know whether or not people realize this,

but the fastest rate of aging

that any of us will ever undergo is puberty.

That is the fastest rate of aging.

And so there’s a huge number of biological processes

that are happening during puberty.

Probably devote a whole episode to puberty.

It’s a fascinating aspect to the life course,

but it is an accelerated period of aging.

And the circadian clock mechanism

sometimes are very intact,

and sometimes they’re a little dismantled

and going through some change,

but prioritize the duration of sleep

for adolescents and teens.

Now, if that means they’re sleeping until 2 p.m.

and then waking up, and then they’re up all night,

the up all night part can become a problem,

especially with all the devices,

texting in their rooms or playing video games.

Morning and evening sunlight would be ideal,

but some kids are just going to sleep

through the morning sunlight.

However, if you were to measure their temperature,

what you would find is that their temperature minimum

would come later in the morning.

It’s not going to be 8 a.m.

It’s going to be maybe even 10 a.m.

if they’re sleeping until 11 or 12,

or it might be 8 a.m. if they’re sleeping until 10.

Remember, temperature minimum is two hours

before your average waking time, typically.

So in teens, it maximizes the total amount of sleep.

Try and get regular sunlight either in the morning

or in the evening or both,

but if they’re sleeping through the morning sunrise,

that’s probably not as much of an issue.

Waking them up and depriving them of sleep

is probably worse because their Tmin,

their temperature minimum, is actually falling later.

So their circadian dead zone is later, et cetera.

So I think with adolescents and teens,

it makes sense to kind of give them a little bit more rope

in terms of allowing them some leeway

to adjust their own schedule.

Some schools are even starting classes later

on the basis of some very good biology

to support this late-shifted rhythm

and this extended sleep phase.

There are data from Dr. Jamie Zeitzer,

Department of Psychiatry and Behavioral Sciences,

and others at Stanford,

showing that turning on the lights in the room of a teen

before they wake up helps them get more sleep

the subsequent night.

It also tricks them into going to sleep

a little bit earlier,

but it gives them about 45 minutes more of deep sleep,

and that’s been shown statistically.

Total sleep time increases as well.

If they’re hiding under the covers,

that’s not going to work,

but their eyes don’t have to be open.

I know a few parents now that are coming in

with a flashlight and flashing their kids

over their eyelids before they wake up

in hopes of getting this to work.

Some have told me this is working.

That’s not part of a standard study,

but it does seem to work because,

now you should know why,

because if light’s getting through the eyelids

and it’s, say, 8 a.m. and the kid is still asleep

and they’re going to wake up at 10,

you’re giving them light just after

or around their temperature minimum,

which is going to make them want to go to sleep earlier.

And in the case of teens,

for some reason we don’t quite understand,

sleep longer, about 45 minutes longer,

spend more time in deep sleep.

Adults can do this too.

If you can persuade someone or put your lights on a timer

for lights to go on before you wake up,

that’s really going to help you wake up earlier.

Okay, so if you’re starting to hear

some themes are really resounding over and over again,

that should be reassuring to you, right?

These are core mechanisms.

Fortunately, there aren’t 1,000 different mechanisms.

Now, in the elderly,

there’s a real tendency to want to go to sleep very early

and wake up very early.

And people should talk to their physician.

There is some evidence that melatonin levels

and patterns of melatonin secretion

can become a little chaotic in elderly folks.

What do I mean by elderly?

Well, it’s going to differ.

Rates of aging differ, right?

You see some 65-year-olds that are struggling to move

and seem much older than some 65-year-olds

that are still hustling around and have tons of energy.

There’s a lot of variation.

Some of it’s genetic, some of it’s lifestyle factors.

It really varies.

Certainly lifestyle factors can play an important role

in rates of aging.

I think that the most prominent results

from sleep and circadian rhythms in the elderly

are they need to get as much natural light,

even if it’s through windows.

I realize that some elderly folks

can’t get outside as easily.

It’s not safe for them to do it.

They can’t move around as easily.

Exercise can come in various forms.

For people that can’t get outside

and get a ton of sunlight by jogging or cycling,

they’re not able to do that.

Light through a window in that case, open window ideally,

but for temperature reasons, et cetera,

sometimes the window has to be closed.

Getting people near that window

and away from artificial light early in the day

and away from artificial lights during the night phase

can have a tremendous effect.

And in the elderly,

that’s when melatonin might be a viable option.

And this should be discussed with a physician, of course,

but you’re way past the puberty time point.

In most cases, people who are in their 70s and 80s and 90s

are not churning out a lot of GnRH

and luteinizing hormone to begin with.

And that’s where struggles with falling asleep

and staying asleep,

all the same parameters and things we’ve described before

still apply, light, exercise, temperature, et cetera,

but that’s where melatonin might be of greatest benefit.

And again, I’m not pushing melatonin here,

but I think for elderly folks who are having trouble

falling and staying asleep, that might be worthwhile.

There are, and I should just also mention

that regular schedule for folks that are elderly

and as much natural light as safely possible,

those are going to be the key levers

for adjusting sleep and circadian schedules.

I’ve mentioned before on previous podcasts,

other supplements besides melatonin.

And some of those supplements are quite good for sleep.

I’m not a supplement pusher.

I am somebody who takes supplements.

I believe in them.

Some have worked for me, some have not worked as well,

but I certainly believe in getting the behaviors right,

whether or not it’s NSDR protocols,

viewing natural light, exercise,

it’s hot baths or cold showers or what have you,

behavioral protocols first.

There are some supplements

that I’ve mentioned in previous podcasts,

but I’ve seemed to get a lot of questions about.

So I just want to take a couple of minutes

and just talk about some of the supplements

that can be beneficial for helping turning off thinking,

accessing deeper sleep,

and even being able to compact your sleep schedule

into a shorter period of hours,

meaning getting by well with less sleep.

People take a lot of sleeping pills.

I’m not going to tell people not to take sleeping pills.

They can be very problematic, habit-forming,

high side effect incidents in many cases.

Some people can handle them just fine.

Again, I’m not a physician, don’t prescribe anything,

professor, so I profess a lot of things,

some of which are my opinion.

Although, if you look at the scientific literature,

there’s some impressive data

around some non-prescription drug type supplements

that have fairly high safety margins that you might consider,

but you should talk to your doctor always

before adding or taking anything

out of your health regimes, right?

Your health is not my responsibility,

it’s your responsibility, so be a stringent filter.

Along those lines, one of the most powerful

and useful tools that I’ve mentioned here on many times,

and I plan to mention many, many more times,

is the website,

which I have no affiliation with,

but is a wonderful site that links you

to quality peer-reviewed studies

related to just about any supplement,

including some safety warnings.

We’ll also tell you what subjects,

whether or not it was rats, cats, elderly folks, or kids,

that a given study was done on, which is important,

can be kind of hard to pull from sites

where people are just advertising supplements, right?

They usually don’t tell you what the study was

and who were these rats, who were these kids.

Et cetera.

There are three supplements that, at least for me,

have had a tremendously positive effect on my sleep

that some of you might consider.

I would say, if you’re doing everything properly,

behaviorally, and you’re still having issues,

then supplements might be a good thing for you.

Or if you are traveling and you want a little bit

of extra help in buffering your sleep wakefulness protocols.

Some people like to go just to the supplements.

They’re like, what should I take?

I have people in my life that are like,

just tell me what to take.

I’m more of, here’s what you might want to do or not do,

but, and then think about what you might want to take

or not take, but personal preference,

and it’s free country, so you can do what you like.


So magnesium has been shown to increase the depth of sleep

and has been shown to decrease the amount of time

that it takes to access sleep, to fall asleep.

It comes in various forms.

I’ve talked a bunch of times about magnesium threonate,

T-H-R-E-O-N-A-T-E, threonate,

which seems to be the more bioavailable form of magnesium,

and magnesium threonate, it seems,

is shuttled preferentially to the brain,

which is where you want it,

and there are certain transporters.

It actually engages the GABA pathway,

which tends to turn off certain areas of the forebrain,

allows you to fall asleep.

There is a study, if you would like to explore it,

since people serious about supplementation

might want to explore the study,

which is ATES et al., A-T-E-S,

dose-dependent absorption profile

of different magnesium compounds.

Looks to me like a quality peer-reviewed paper.

I can put the link in the caption,

and it explores all the different forms of magnesium.

It does seem like magnesium glycinate

can be similar to magnesium threonate

in terms of which tissues it’s shuttled to.

Magnesium malate, M-A-L-A-T-E,

is preferentially shuttled to the muscle, it appears,

as opposed to the brain,

so it’s going to be more of a muscle repair type thing

or restoring magnesium stores in the periphery

as opposed to the brain.

Magnesium citrate has another name

that I won’t mention in jest

because magnesium citrate’s main effect,

at least on me and the people I know,

seems to be a laxative effect

as opposed to a cognitive effect.

There’s also some evidence

that magnesium threonate can be neuroprotective.

Those data come from quality labs,

mostly rodent studies, not human studies,

but it’s kind of interesting.

And again, the safety margins for these things

tend to be pretty high,

but anytime you’re going to take something new,

you should approach it with caution,

especially since magnesium could be involved

in heart rhythm and things of that sort.

The other supplement that has been very beneficial for me

is theanine.

So this is T-H-E-A-N-I-N-E, theanine, T-H-E-A-N-I-N-E.

Theanine activates certain GABA pathways,

which are involved in turning off top-down processing

and thinking, making it easier to fall asleep.

And theanine, 100 milligrams to 300 milligrams,

has a calming effect.

Theanine is now showing up

in a number of different energy drinks

and even some coffees as a way to try and get people

to ingest more of a given type of coffee

because the idea is it would take away the jitters

and the anxiety, allowing people to drink more coffee.

I’m talking about taking magnesium and theanine

30 to 60 minutes before bedtime,

not during the day to quell anxiety,

but rather 30 to 60 minutes before bedtime

with or without food for me has made a difference.

And the combination of those two things has really helped.

Theanine for sleepwalkers can be a problem.

It does increase the intensity of your dreams.

It gives you very vivid dreams.

So for sleepwalkers or people that get night terrors,

stay away from theanine is my advice.

Magnesium, theanine might be something to explore

for those of you that don’t have those issues

with the emphasis on might.

And then I’ve talked about a compound.

And last time I talked about the mechanisms of apigenin,

which is a derivative of chamomile, A-P-I-G-E-N,

which acts as a little bit of a hypnotic

by activating chloride channels,

hyperpolarizes neurons, increases GABA in the brain,

basically makes you feel a little sleepy.

And chamomile, for those of you that read your,

what was it?

The Peter Rabbit snuck into Mr. McGregor’s garden,

ate the chamomile, fell asleep.

Mr. McGregor came back.

Okay, anyone flashing back to elementary school?

Okay, there’s a story about chamomile

having these kind of sedative-like effects.

Apigenin is highly concentrated.

Chamomile also has anti-estrogenic effects.

So if you want to keep your estrogen up,

you might want to be cautious about apigenin.

That’s where things like become really useful

because you can go to examine, you put in apigenin,

and it’ll tell you all the things that it does

and all the things that it does

can sometimes include things that you had no idea,

like reducing conversion of certain androgens to estrogens,

which you might like, or you might want to avoid.

That’s up to you and where you want your estrogen levels,

depending on who you are

and what your life circumstances and goals are.

A few other things that can help the transition to sleep

are things like 5-HTP, L-tryptophan.

I’ve talked about why I’m not a fan of those for me.

They tend to throw me into deep sleep

and then I wake up and I can’t fall back asleep.

So I don’t like to tinker with my serotonin system.

I don’t like to tinker with my dopamine system

for entirely other reasons,

but none of which are particularly concerning.

It’s just that I find that if I increase my dopamine

by taking L-tyrosine in pill form,

then I crash really hard the next day.

Or if I take 5-HTP or L-tryptophan,

I fall deeply asleep and then I wake up.

But I did mention that there might be ways

to make sleep more compact.

And so this is actually a request to you.

I had a really interesting experience when I was a postdoc.

I went for the first time to an acupuncturist.

I know there are varying thoughts

and opinions out there about acupuncture.

I can’t say that I benefited so much from the acupuncture.

There are now quality peer-reviewed studies

showing, published in Neuron,

Cell Press Journal, excellent journal,

showing that acupuncture can stimulate

some anti-inflammatory compounds,

depending on where the acupuncture is done.

This is a really good study.

This came out last year.

I talked about this on Instagram.

I may talk about it again.

As well as certain acupuncture sites

that increase inflammation.

So, you know, you can get different types of effects.

You can’t just say acupuncture is great across the board.

And I’m assuming that the acupuncturists know

which sites are good for increasing inflammation,

which ones are good for decreasing inflammation.

However, this acupuncturist that I went to

gave me these red pills.

He said, these are minerals for sleep.

And it was remarkable.

I took the red pills.

Isn’t that a thing now?

Take the red pill.

I don’t know what that means because I’m not tuned in.

But these red pills look like little M&Ms.

I took a couple of them on his suggestion.

And I fell deeply asleep.

And four hours later, woke up feeling incredibly rested,

more rested than I’d ever felt in my entire life.

And I never required more than four hours sleep.

Unfortunately, acupuncturist moved away.

I never figured out what was in those red pills.

I didn’t get a chance to do the mass spectroscopy.

And I still wonder.

He said they were minerals.

So somebody out there knows what these red pills are

and what this compound is.

And it was incredible.

And I would love to know what those are.

So if you know,

please don’t go taking red pills at random

to try and recreate this non-experiment experience of mine.

But please do contact me if you find out

or if you’re an acupuncturist

and you know what these mysterious red pills were

because they were pretty awesome.

Once again, I’ve thrown a tremendous amount

of information at you.

I hope you will figure out your temperature minimum

and start working with that

to access the sleep and wakeful cycles

that you want to access.

I hope that you’ll explore NSDR.

You might want to explore supplementation

if that’s your thing.

You have now access to a lot of mechanism

about sleep and wakefulness.

But in keeping with the theme of this podcast

where we stay on topic for an entire month

or even slightly more,

we are not done with sleep and wakefulness.

I know this is very different

than the typical podcast format

where one week it’s how to become superhuman.

And the next week it’s how to develop growth mindset.

It’s kind of all over the place with episode to episode.

We are staying on track because I really believe

that as we drill deeper and deeper into these mechanisms

and you start hearing some of the same themes

again and again,

you’re going to start to develop an intuition

and an understanding of how these systems work in you

and your particular life circumstances.

And my goal is really to eventually become obsolete.

It’s what my graduate advisor

used to call the hit by a bus principle.

She had a somewhat morbid sense of humor

and used to be, well, if I get hit by a bus tomorrow,

what are you going to do without me blabbing at you here?

So I don’t want to get hit by a bus.

I plan on living a very long time

if I have anything to say about it.

But were I to get hit by a bus tomorrow,

what would you do for your sleep and wakefulness, right?

You could put a comment on YouTube, which I hope you’ll do.

But if I were hit by a bus and killed,

then I wouldn’t be able to answer your question.

So know your temperature minimum.

Understand light in the early part of the day is valuable.

Light when you want to be awake,

provided it’s not so bright, it’s damaging.

It’s great for you whether or not it comes from screens

or sunlight, but sunlight’s better.

Avoid light in the four to six hours

before your temperature minimum,

or else you’re going to delay your clock

unless you’re traveling and that’s what you want to do.


Use temperature, increase temperature to shift your clock.

Decrease temperature to delay your clock.


Map out your temperature and understand it.

You don’t have to know degree by degree across the day.

Know your minimum, know your maximum temperature

in your 24-hour cycle,

and you will feel great power through that

because then you’ll know also about these ultradian cycles,

these 90-minute cycles within which you can do focused work.

Don’t expect the focus to come early.

Expect the focus to come in the middle

and then kind of taper off.

I talked a little bit about kids,

a little bit about elderly, about parenting.

We are going to continue.

There’s going to be more.

But now shift workers, travelers,

people that are jet lagging themselves at home,

you now have levers in place.

Information can be powerful,

but you have to implement it in ways,

obviously safe ways and reasonable ways.

But implementing this knowledge

in the ways that you trust are safe and reasonable for you

is going to be the way that you can develop

a bit of a laboratory about yourself.

I loathe the term biohacking.

Sorry, biohackers.

I don’t believe in hacking anything.

I believe in understanding mechanism

and applying the principles of mechanism

for which there are large bodies

of quality peer-reviewed data

and even a whole center of mass

around certain biological principles,

like the effects of light and temperature minimums

that will allow you to shift your biology

in the ways that you want to go,

that will allow you to shift your psychology

in the ways you want to go.

Next podcast episode,

we are going to talk more about a few things.

First of all, we’re going to answer more of your questions

because during office hours,

I didn’t get to all your questions

from the previous episode.

So I do read the comments and we’re paying attention

and figuring out the most common questions.

We are going to get to some of the harder topics.

Someone came at me,

it’s always fun when somebody does this,

and they say, well,

these are just the kind of basal low-level questions.

What about the big stuff?

What about dreaming and lucid dreaming and consciousness?

Look, I’ll talk about that stuff.

And I’m planning to do that,

some of which in the next episode

and the following episode, maybe even.

But I want to give you data.

I want to give you things that are supported by data.

So I will try to speculate as little as possible

because this is a podcast about science

and science-based tools for everyday life.

This is not about me speculating.

Many people have speculated

about the role of sleep, dreaming, and consciousness.

Fascinating topics and a rather circular argument, frankly.

It’s been going on for centuries.

Someday we’ll get there.

Right now, we’re concentrating

on these deep biological mechanisms

that make you who you are

and allow you to feel certain ways, good or bad,

allow you to function physically in certain ways,

good or bad, and give you more of a sense of control.

That’s my goal here.

Many people have quite graciously asked

how they can help support the podcast.

First of all, thank you.

We appreciate the question.

You can support the podcast

by subscribing to the podcast on YouTube,

as well as subscribing on Apple or Spotify.

And you can also leave us comments

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That really helps.

We would hope the feedback would be positive,

but nonetheless, leave us feedback, ask questions.

We will use those questions

to create future content for the podcast.

As well, if you can recommend the podcast

to friends and family and other people

that you think might find the information of use,

that’s terrific.

And check out our sponsors

that we mentioned at the beginning.

That’s a really great way to help support us

and our ability to bring you this information.

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 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.

Thanks so much for your time and attention.

I really appreciate it.

See you next time on the Huberman Lab Podcast.

And as always, thanks for your interest in science.

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