(orchestral music)
- Hey Brain Stuff, Lauren here.
According to research from
Johns Hopkins University
up to 90% of people in the United States
habitually consume caffeine
at doses that make it
by far America's most popular drug.
And we're not even the
world leaders in coffee
consumption per capita.
Lookin' at you, Finland
in the Netherlands.
Caffeine is a natural
compound found in plants
like cacao, coffee and tea.
And researchers think
that it's perky properties
have made it part of humanity's diet since
before the dawn of recorded history.
So, let's take a look
at why it's so popular.
By delving into the
chemistry of the human body.
Every cell in your body
breaks down a biochemical
called Adenosine Triphosphate, or ATP,
to get the energy it needs to do stuff,
you know, contract your muscles,
transmit electrochemical
signals in your brain, build new cells.
That kind of thing.
So, when your cells do any kind of work,
from helping you fight a
bear, to helping you read
and understand a probably
harmless book that you found
in the basement of a
creepy cabin in the woods,
those cells wind up
excreting a few by-products
from the breakdown of ATP.
One of them is a compound
called Adenosine.
In the brain, Adenosine is
known to cause drowsiness.
When it binds to
specialize neuroreceptors,
that it fits into like a
chemical key into a lock,
Adenosine slows down,
aka inhibits the activity
of particular neurons.
Those neurons happen to be in
parts of the Basal Forebrain
that control whether
you're awake or asleep.
Adenosine makes those
neurons fire less often,
and less activity equals drowsy.
Caffeine just happens to
fit into the same receptors
in the brain as Adenosine,
sort of like a lock pick.
So, part of what's happening
when you drink coffee
or cola or whatever, is
that less Adenosine can
reach those receptors.
Furthermore, where Adenosine
slows down neural activity,
caffeine speeds it up.
Those neurons start
firing more than usual.
This extra activity leads to
caffeine's physical affects
because our brains are dumb.
One job that our Hypothalamus
has is to monitor
for extra neural activity
because that's a sign of stress
or heightened arousal, or danger.
Basically, your Hypothalamus
can't tell the difference
between an espresso
and an attacking Kaiju.
So its response is the same either way.
It signals your pituitary
gland and your sympathetic
nervous system that there is an emergency
and so they'd better get
the adrenal medulla to
release some epinephrine, aka adrenaline.
Adrenaline, of course, being
the fight or flight hormone,
that puts your body on red alert.
It makes your pupils dilate,
to your airway opens up,
your heart beats faster and
your blood pressure rises.
Skin surface, blood vessels
constrict to slow blood flow
from potential cuts, and
increase flow to your muscles.
Your liver releases sugar
into your bloodstream for
extra energy and your muscles
tighten up, ready for action.
In other words, your real awake.
The half-life of caffeine in
your body is about six hours.
Meaning that if you drink
a cup of coffee containing
about 200 milligrams of caffeine at 3 PM,
you'll still be left with
about 100 milligrams by 9 PM.
And about 50 by 3 AM.
Your brain may still be
having trouble binding enough
Adenosine to release slow down.
Thus keeping you awake, or
at least preventing deep
restful sleep.
That's one reason why
experts recommend moderation
when it comes to caffeine intake.
Less than 300 milligrams per day,
which equals about two cups of coffee.
So, do you have a caffeine habit?
Do you have any caffeine horror stories?
I definitely use coffee
to help me concentrate
and avoid accidental
naps around the office,
but when I have more than
a cup I feel like I can
vibrate right through space time.
Let me know in the comments.
While you're around, give
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and of course, your source
for everything about
coffee and other drugs,
is Howstuffworks.com.
