AMA #8: Balancing Caffeine, Decision Fatigue & Social Isolation
ANDREW HUBERMAN: Welcome to the Huberman Lab podcast,
where we discuss science and science-based tools
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I'm Andrew Huberman, and I'm a professor
of neurobiology and ophthalmology
at Stanford School of Medicine.
Today is an Ask Me Anything episode, or AMA.
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So without further ado, let's get
to answering your questions.
The first question is about the pros and cons of daily caffeine
consumption.
The question reads, what is your opinion on the net benefit
of daily caffeine consumption?
And how can somebody determine if daily caffeine consumption
is right for them?
Well, first of all, I did an entire episode about caffeine.
You can find that by going to hubermanlab.com.
At that website, you can put in caffeine into the search
function, and you'll find links to that episode
in all the formats--
YouTube, Apple, Spotify, et cetera.
And it's timestamped, of course.
You can navigate to the particular topics
most of interest to you.
However, for sake of this discussion,
I can summarize a few of the key points.
The most important thing to understand
is that for most adults--
so that is people about age 18 to 20 and older--
daily caffeine consumption is not
going to be a problem provided it does not induce anxiety,
and certainly provided that it not induce anxiety or panic
attacks, and provided that it does not
disrupt your nighttime sleep.
This is why I always recommend that if you
are going to consume caffeine in any form, coffee, tea, soda,
or otherwise, that you try not to ingest caffeine
within the eight and ideally within the 10
or even 12 hours prior to bedtime.
That's because the half life of caffeine
is such that even if you are able to,
for instance, have a cup of coffee
around 3:00 PM or 4:00 PM and then
fall asleep around midnight, the architecture of the sleep
that you get is going to be disrupted.
For instance, it is very important
that you get sufficient amounts of both slow wave deep sleep
as well as rapid eye movement sleep each night.
And if you consume caffeine too close to bedtime--
and here, I'm defining to close as anywhere from 8 to 12 hours
before going to sleep--
chances are you're not going to get as much rapid eye movement
sleep or slow wave sleep that you would otherwise.
And it is the amount of rapid eye movement sleep
and slow wave sleep that, together,
lead to whether or not you feel you had a good night's
sleep in terms of your next day alertness and cognitive
abilities.
Now, again, some people may find that they
can drink caffeine in the late afternoon, maybe even at night,
and still fall asleep.
But I promise you, even if you're in that category,
you will sleep far better, meaning the architecture
of your sleep will be better, and you
will feel far more rested the next day
if you abstain from caffeine within the eight to 12 hours
prior to bedtime.
And I should also say that none of us are perfect,
myself included.
I will sometimes have a cup of coffee in the late afternoon,
and sometimes that will cause me to stay up a little bit later.
Sometimes it won't.
I don't think you want to obsess or worry
too much about having some caffeine every once
in a while in the late afternoon if you
are still able to fall asleep, but don't
make it a regular habit.
Now, as far as we know, there is no drawback
to consuming caffeine on a daily basis,
again, provided it does not disrupt your nighttime sleep
and provided that does not induce anxiety.
In fact, most of the world consumes
caffeine every single day.
The current estimates are that 90%--
that's right, 9-0, 90%--
of adults throughout the world consume a caffeinated beverage
every single day.
That's a staggeringly high number,
making caffeine the most popular drug on the planet.
In fact, because of the way that caffeine works--
and just to remind you how it works--
it effectively blocks adenosine receptors.
Adenosine is a molecule that builds up in your brain
and body more and more according to how long you've been awake.
It makes you feel sleepy.
Caffeine blocks the adenosine receptor,
and then when it is dislodged from that receptor, whatever
adenosine has built up and is around can then
bind to the adenosine receptor.
It makes you feel very sleepy.
That's the caffeine crash.
So if 90% of the adult population of the planet Earth
is consuming caffeine every day, that
means 90% of the adult population of planet Earth
is blocking their adenosine receptors
for some portion of their daily life,
and then their adenosine is binding to the vacant receptor
once the caffeine has dislodged.
And why are 90% of adult humans consuming caffeine every day?
Well, to feel more energized, more focused,
to have more both cognitive energy and physical energy.
Now, of course, most people are not walking around thinking,
oh, caffeine gives me more energy more focus, et cetera.
Most people are consuming caffeine every single day
and are consuming caffeine every single day in order
to feel, quote, unquote, normal, to be
at their baseline level of cognitive ability,
and physical energy, and so on.
In fact, if you look at the data on caffeine consumption, what
you'll find is that caffeine actually
is a cognitive enhancer.
It can improve learning and memory.
It can increase physical energy.
It can increase mental and physical stamina.
But a feature of those studies that's not often discussed
but that was, however, discussed in the full episode on caffeine
is that studies of caffeine typically
are done by taking chronic caffeine users
and then having them abstain from caffeine for some period
of time, usually four days to two weeks, in which time
they undergo caffeine withdrawal.
They do not feel well.
They get foggy headed.
They have less energy.
There's some malaise, sometimes even some mild depression.
And then what they do is they have
people take caffeine, and take a cognitive exam,
or do some physical activity and compare their performance
to what it was when they were in the withdrawal state.
Another typical form of study on caffeine
is to take people who are naive to caffeine
or who never take caffeine, and then have them ingest caffeine,
and then measure their cognitive and/or physical performance.
And in both cases, you see improvements.
What I'm saying here is that daily caffeine consumption
is not going to lead to improvements
in cognitive ability or improvements
in physical ability above one's baseline
unless you either abstain from caffeine
for some period of time, typically four days to two
weeks prior, or you are not somebody
who typically ingests caffeine.
In other words, 90% of the world's population
is drinking caffeine on a daily basis
to be at their normal level of mental and physical
functioning.
So the question was, is there a net benefit
to daily caffeine consumption?
And here I can reliably say, provided
you don't suffer from anxiety attacks or lack of sleep
from the caffeine consumption, provided that you're
mindful of not ingesting caffeine too late in the day,
there doesn't seem to be any big drawback to drinking caffeine
on a daily basis.
However, there doesn't seem to be any great benefit,
at least in terms of direct effects
on cognitive or physical ability.
So I realize this is a little bit of a convoluted answer,
but we have to be honest with one another here.
Caffeine is a performance-enhancing drug,
but only when compared to the noncaffeinated state.
And 90% of the adult population of the world is caffeinated.
So adding more caffeine above what you would normally consume
is certainly not going to allow you to think better and perform
better physically.
Here's a useful way to think about caffeine.
Most people can pretty well tolerate doses of caffeine,
anywhere from 100 milligrams to 300 milligrams.
It depends on body weight and depends
on your tolerance, tolerance, of course,
based on how familiar you are with the effects of caffeine
and how regularly you consume it.
A typical cup of coffee, which, by the way, does not exist.
Depending on the vendor, depending
on how much water-to-coffee ratio one uses,
depending on whether or not it's French press or it's pour over,
the type of coffee, et cetera, all of that
is going to determine the total amount of caffeine
in that coffee.
But we can set some outer bounds on the total amount of caffeine
that likely exists in a cup of coffee,
and it's probably somewhere between 100 milligrams--
that would be on the weaker side for a six or eight ounce cup
of coffee--
out to about 300 milligrams for the equivalent
six to eight ounces of coffee.
But if you were to brew your coffee very, very strong
or, like me, occasionally throw a shot of espresso in there,
too, you could get that number up
to 400 or 500 milligrams of caffeine.
I personally tolerate caffeine pretty well.
I've been drinking caffeine since I was a teenager, mostly
in the form of brewed unflavored yerba mate tea.
It's important to stay away from the smoked varieties of yerba
mate if you're going to get your caffeine from your yerba mate.
The smoked varieties can be carcinogenic.
The nonsmoked varieties don't seem to have that property.
But there's a lot of caffeine in yerba mate,
so I'll drink yerba mate and have for many, many years.
Or I'll drink black coffee, or espresso, or espresso
americano, things of that sort.
That's my preferred source of caffeine.
Most people are drinking coffee to get their caffeine
and, I would say that, if you are
going to drink your caffeine, drink it
in the early part of the day, as I mentioned earlier.
I am a big proponent of delaying your first caffeine
intake until at least 90 minutes after waking in order
to avoid the afternoon crash.
I've talked a lot about this on the podcast.
There are a lot of clips on the internet explaining
the rationale behind that.
And if you do experience an afternoon crash in energy,
I do recommend delaying your morning caffeine intake to 90
to 120 minutes after waking.
Now, for people that want to get more
of a true cognitive-enhancing and performance-enhancing
effect from caffeine, again, you're
going to have to abstain from caffeine for about four days.
For regular caffeine drinkers, that's going to be difficult.
That is going to lead to headaches.
That's going to lead to brain fog.
That's going to lead to feelings of malaise.
In fact, the last time I took four days off
or even a week off from caffeine consumption
was when I was sick.
I don't get sick very often, but when I am sick,
I generally abstain from caffeine.
And sometimes I wonder whether or not
the malaise I feel from whatever viral or bacterial thing
I might be dealing with when I'm sick
is, in part, the malaise of caffeine withdrawal.
I certainly notice I feel much better when
I return to drinking caffeine, but that
tends to coincide with feeling relief
from whatever sinus symptoms and other symptoms I
might have been experiencing from the illness.
So it's not a good experiment.
I can't tease apart those variables.
So the short answer is, for most adults,
there does not seem to be any major downside to consuming
caffeine.
And there have been scattered reports here and there
in humans, showing that ingesting caffeine can increase
dopamine receptors, which will effectively
allow you to get more out of the dopamine that you produce.
This is why caffeine has a mood elevating as well
as energy-elevating effect.
I should point out that some people just cannot tolerate
caffeine.
It makes them too jittery, too anxious.
They start sweating.
They get heart palpitations.
It's very hard for these people to build up a tolerance
to caffeine that allows them to enjoy it.
These are the people that can even
feel a fluttering of the heart and a lot of energy
left from decaf coffee, something
that, to me, is just a foreign.
Concept but some people are just that sensitive to caffeine
that even the small amounts of caffeine in chocolate or decaf
coffee make them feel too alert.
And they should abstain from caffeine.
I don't think they are, in any way,
harming their health by abstaining from caffeine.
Then there's the issue of children, and adolescents,
and teenagers, and young adults ingesting caffeine.
And I covered some of this in the episode about caffeine,
but there's been a lot of debate as to
whether or not caffeine can cause osteoporosis,
whether or not it can leach calcium out of the bones,
whether or not can stunt growth.
Frankly, there's not a lot of evidence
for those sorts of claims, and yet the developing brain
is a very tender and malleable environment.
And somebody who started off his career
as a developmental neurobiologist,
studying developmental brain plasticity and wiring,
it does sort of make me cringe to think about children younger
than the age of, say, 14 ingesting
large amounts of caffeine in any form-- soda, coffee, tea, et
cetera.
Despite the fact that there's very little evidence
that it can stunt their growth, I don't personally
like the idea of the young brain being bathed
in an adenosine receptor antagonist, which is
effectively what caffeine is.
As much as possible, one wants the developing brain
to develop in a milieu of unencumbered, nonchemically
encumbered interactions between neurotransmitters
and their receptors, unless, of course,
there's a clinical need for a prescription drug,
or a supplement, or some modification
of a nutritional program specifically
to up or down regulate the dopamine system
or up or down regulate the serotonin system.
But those are the sorts of decisions
that really should be made in close oversight
and recommendations by a psychiatrist.
So the short answer around daily caffeine consumption
in young people, meaning 14 and younger,
is avoid it if you can.
Have your children avoid caffeine if they can.
The occasional bit of caffeine is probably not
going to be a problem.
The amount of caffeine in small amounts of chocolate, probably
not going to be a problem.
But caffeine in the form of energy drinks, sodas, coffee,
tea for children younger than 14 just
seems like a bad idea from everything
we understand about brain wiring and the trajectories of brains
that develop with a lot of chemical adjustment
from other sources, like caffeine.
Now, for kids age 15 to, say, 18 or 20, a lot of brain wiring
is still occurring, but a lot of it has been completed.
So probably not as risky to consume caffeine
every once in a while or maybe even on a daily basis.
But there are two--
I think there are great advantages
to limiting the amount of caffeine that one ingests.
And of course, in the adolescent and teen years,
nowadays a lot of kids are consuming
energy drinks and soda.
And some of those energy drinks and so
does contain a lot of caffeine, anywhere
from 200 to 800 milligrams of caffeine.
And nowadays, more sodas and energy drinks
contain other things like amino acid precursors
to neuromodulators, like dopamine.
So for instance, a lot of energy drinks
now contain L-tyrosine, which is a precursor to dopamine.
A lot of them will contain L-theanine.
I've talked about L-theanine as a supplement that
can promote more restful sleep if taken
30 to 60 minutes before sleep.
The reason why a lot of energy drinks, and sodas,
and, frankly, now coffee brands are including theanine
in the coffee, or energy drink, or soda
is because it tends to have a mild anxiety-reducing effect.
And it reduces the jitters that caffeine creates.
And so that's actually a trick that these companies are using
in order to get people to ingest more caffeine because,
by including the theanine, it's preventing the kid or adult
from feeling too jittery.
And therefore, they can continue to consume that drink
without feeling like they're overstimulated.
So if I were to take the parental neuroscientist adult
voice here, I would say avoid caffeine intake
as much as you can until you're about 18 years old.
But I'm realistic.
I realize that adolescents and teens age, say,
14, or 15, out to 18, and older are
going to be consuming caffeine in the form of energy drinks
and sodas.
But reducing the total amount of caffeine
that one is ingesting in those years,
it just seems really advantageous,
again, m all the same reasons I mentioned earlier.
You don't want the young brain bathing
in a bunch of exogenous, meaning externally introduced
neurochemicals or in things like theanine or L-tyrosine.
If you're going to indulge in caffeine, or in energy
drinks, or theanine, or L-tyrosine, for that matter,
that's the sort of thing that probably is best left
for people 18 and older.
And even there, if one finds that caffeine is for them,
as do I, I think always best to try and get your caffeine
from a clean source, a clean source meaning
something that contains just coffee or just tea.
Again, this isn't a knock on energy drink specifically,
but you really have to make sure that whatever energy
drink you're going to consume, you know what's in it.
You recognize what the different ingredients do.
And you recognize the potential of ingesting
those ingredients chronically over and over again.
And I've talked to a little bit about this
on previous podcasts, and I'll get into this.
Again, maybe we'll do an entire episode about energy drinks
because they are so commonly consumed nowadays.
Now, getting back to the original question
about daily caffeine consumption,
this person goes on to say that, for them--
OK, this is their personal experience--
after a few weeks of consumption of daily caffeine,
the negatives start to outweigh the positive ones.
They're getting poor-quality sleep,
lack of appetite, anxiety, et cetera.
And when they don't consume caffeine,
they find it a lot easier to be mindful,
and their meditation practice is much better.
But they're lethargic and less motivated.
So what they're describing are all the classic symptoms
of caffeine overuse, probably not abuse in this case,
although caffeine can be truly abused,
people taking caffeine pills, et cetera in large quantities.
We're not talking about that.
But this person is describing the classic pattern
of overuse of caffeine and the classic pattern of withdrawal
from caffeine when they stop taking it.
So what should somebody like this do?
And I think that's an important question
to answer because I think a lot of people
fall into this category.
They drink caffeine every day.
They're no longer getting the performance-enhancing effect
of caffeine, so they're taking it just
to be normal or feel like they can focus normally and have
normal amounts of energy.
But then if they try and come off, they feel worse.
There are a couple of ways to do this.
You can taper your caffeine intake off
over the course of four to seven days.
But most people don't have the discipline
or don't want to spend the time doing that.
But if you want to, the way you would do that is you
would cut it by about 10% or 15% per day.
You could do that by volume, or you
could do that by concentration of coffee, that sort of thing.
A simpler way to go about all this that still will allow
you to get some of the performance-enhancing effects
of caffeine and yet experience far less withdrawal
would be two things.
First of all, just halve your amount
of caffeine intake for two or three days.
So again, that could be by volume,
or it could be by concentration, probably easiest
to do by volume.
And so instead of drinking an eight ounce
coffee in the morning, maybe you do four ounces
of regular coffee, four ounces of decaf,
or you just have the four ounces of coffee.
You do that for three or four days,
and then you take perhaps one full day off from caffeine,
maybe another full day off.
You're going to feel a lot less bad on those
two days, having cut your caffeine intake in half
in the previous four days then you would
if you just went cold turkey.
And then you go back to ingesting caffeine,
but you go back to ingesting caffeine at that 50% dose
or what used to represent that 50% dose of caffeine for you.
And you just continue that way on a daily basis,
and then every once in a while, when
you want the performance-enhancing effects
of caffeine, you go back to what was your original dose, which
is now double what you're taking on a daily basis.
So what we're really talking about here
is not going cold turkey.
We're not talking about quitting caffeine indefinitely.
What we're talking about is cutting the amount of caffeine
that you drink in half for about four days, plus or minus a day,
and then taking two days off from caffeine completely.
And then going back on that half dose of caffeine indefinitely.
That's your new baseline of caffeine intake.
And then every once in a while, if you
need a bit more of a lift, you ingest twice as much caffeine
or a coffee that's twice as concentrated.
We should acknowledge that most people aren't
going to be really precise about the amount of ounces
and the amount of caffeine.
Nonetheless, it's pretty straightforward
to know that you're reducing your caffeine intake.
Certainly, it's clear to know if you're
ingesting no caffeine for a couple of days.
And it's pretty clear when you're doubling
the amount of caffeine.
But you don't have to worry so much that you're exactly
doubling the amount of caffeine.
You can drink one and a half times
as much as you happen to drink on the day before,
or you could drink three times as much.
You would definitely feel it if you drink three times as much.
One very important thing to recognize
is that, on any day where you really spike your caffeine
intake above baseline, no matter where that baseline is
when you start-- it could be 0.
It could be 400 milligrams.
It could be 200 milligrams.
When you double that intake, you will get a big boost of energy,
and the next day, you're going to feel the crash from that.
You're going to feel more lethargic.
You're going to feel not so good.
This has to do with dopamine receptor modulation.
This has to do with adenosine receptor modulation.
The important thing to do is not continue
to consume that elevated level of caffeine, which
is what most people do, and then they set a new hire baseline
just to feel normal.
The key thing is to just manage to get through that crash day,
manage to get through that one day
where you feel a little less good or maybe even down a bit.
Get outside a bit.
Get some more sunshine.
We know that spikes your cortisol in a good way.
It can increase the catecholamines, dopamine, et
cetera.
Get a little bit more sunlight.
Get a little bit more movement.
Get outside.
Do something to offset those feelings of malaise,
and then get right back to your original goal
level of caffeine each day.
There's no use in getting so quantitative that you make
your life miserable, you're measuring things out
like a laboratory chemist.
If you're that type and you want to do that, be my guest.
But unless you're taking caffeine in pill form,
it's very, very hard to get extremely exact
about the amounts of caffeine that you're ingesting.
So it is OK to eyeball it, but understand the contour
of how caffeine works and what the caffeine
performance-enhancing effect comes from.
It comes from a caffeine intake above baseline.
Understand that any time you go above baseline
with your caffeine intake, there's
the potential of some anxiety.
Understand that there's going to be a slight withdrawal
effect that lasts about 24 to 48 hours.
Battle through that short period,
and you'll be right back where you started
and where you need to be so that you can enjoy caffeine
on a daily basis and derive the benefits because there are
many benefits to drinking caffeine and avoiding
some of the potential hazards.
And again, if you're a young person,
I recommend delaying that caffeine intake maybe, I
don't know, 10 years.
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