Oh morning even if the Sun is out fog
and rain still smother your sleepy soul
or not maybe you're more of a morning
person
but it's an obvious fact that many of us
do need some coffee or tea to prepare us
for workers school coffee and tea are
some of the most widely consumed
beverages on the planet but how does
caffeine affect your body and mind
throughout the day and is it bad for you
or addictive if you want to see the
richest brew up some more science facts
for you don't forget to like this video
subscribe and ring that Bell so that you
never miss out on our videos let's begin
with the basics
what is caffeine caffeine is a stimulant
of the central nervous system and is
classified as a methyl xanthine
methylxanthines are a subclass of a
class of chemicals called xanthi the
methyl part of its name tells you that
it includes a compound similar to
methane called a methyl group xanthines
are very common in many organisms
including the tissues of humans so it's
no surprise that coffee and tea to
different plants that are only distantly
related develop the ability to
synthesize caffeine but why would they
do that well like all plants coffee and
tea have to deal with insects that want
to eat their leaves and fruit so their
leaves and seeds produce caffeine
juvenile coffee plants in particular
also leach caffeine into the surrounding
soil they do this to stop the growth of
other plants nearby that way there's
less competition meanwhile tea plants
produce caffeine in two places
cellular vacuoles which are a type of
organelle containing organic compounds
and around the vascular bundles which
are like the veins and arteries of a
plant the first is thought to discourage
plant eating animals from munching the
leaves and the second is thought to
fight off fungi that also want to bite
other plants like Kola nuts contain
caffeine as well in fact around 60 plant
species produce the stuff by now you
must be tempted to spit out your latte
in disgust who wants to drink
insecticide even if it comes from a
plant don't worry the chemical is only
lethal for bugs because bugs are much
smaller plants use caffeine to an
use the effects we associate with a
caffeine buzz but they're applying it to
a tiny organism that just can't take it
the lethal dosage for a human being is
about seventy-five to a hundred cups in
a day for a 154 pound adult caffeine's
ld50 the dosage at which half of a mad
scientist unlucky test victims fatally
overdosed is about 150 to 200 milligrams
for every 2.2 pounds in an adult body
there's no way you're getting that much
caffeine inside of you even the most
ridiculous energy sports drink has no
more than about 300 milligrams of
caffeine in total so what are those
effects how does caffeine stimulate you
we all know that caffeine is a central
nervous system stimulant and that it has
effect on your brain
caffeine targets many parts of your
brain including the cerebral cortex the
region of the brain devoted to memory
consciousness and language that might
explain why you're a little more
articulate and aware after a glass or
mug of your favorite caffeinated
beverage but more generally and more
importantly it eliminates drowsiness
that drowsiness that you want to
eliminate with coffee goes away when
caffeine binds to the adenosine
receptors which prevents adenosine from
working and that makes way for the
brains natural stimulants but caffeine
also stimulates the medulla oblongata
the upper part of your brainstem that
part of your brain controls vital
involuntary functions like the beating
of your heart breathing vomiting and the
dilation and contraction of major blood
vessels that's why a strong cup of
coffee and tea also raises your heart
rate and increases blood flow or
restricts it see that's where things get
a little complicated one of the ways
caffeine works is by inhibiting a
cellular enzyme called phosphodiesterase
and phosphodiesterase is how your body
puts the brakes on your cells favorite
party drug cyclic adenosine
monophosphate or camp camp promotes
activity in your cells
so when caffeine blocks at
phosphodiesterase yourself go into
overdrive thing is overdrive is a
relative term since you're different
cells serve different functions when
caffeine binds with the cells that make
up your blood vessels the overload of
camp causes those vessel
to dilate which is why coffee can have
different physical effects depending on
the dosage or the individual drinking it
it will definitely make you think and
talk faster but it may or may not raise
or lower your heart rate that is at
normal doses we should probably start
talking about higher doses the doses
that won't kill you but might give you
some unwanted side effects one
unpleasant side effect caffeine fans
know is that it can give you a vicious
need to go to the bathroom at normal
doses like those you find in a single
cup of coffee or a few cups of tea this
won't happen so fast but what if you
have two to three cups of coffee or five
to eight cups of tea now you're talking
around 250 to 300 milligrams of caffeine
at that point caffeine acts as a
short-term diuretic it stimulates your
urine output which is a nice way of
saying it makes you pee like a racehorse
but caffeine can do other bad things
you've probably heard of the coffee
jitters
those are real it's bad enough if you're
a mentally healthy individual with no
anxiety issues but if you suffer from
anxiety caffeine can absolutely make
your condition worse of course if you're
watching this and have anxiety we
recommend you talk to your doctor about
drinking caffeine before you toss out
all of your coffee and tea but one of
the most burning questions people have
about caffeine is whether or not it's
addictive well not exactly
remember those adenosine receptors if
you drink coffee or tea every day your
brain can sense that those receptors are
getting blocked by caffeine after a
while it will make more adenosine
receptors to compensate and as we've
already discussed those receptors induce
drowsiness when adenosine binds to them
so if you skip your daily caffeine for
the first time in forever you'll be more
drowsy than normal and there are other
withdrawal effects of caffeine headaches
irritability etc but the important point
here is that caffeine although it is a
stimulant doesn't work like other
stimulants stimulants like illicit
substances and amphetamines work by
blocking dopamine transporters these
transporters remove the neurotransmitter
dopamine from your synapses but illicit
substances don't block dopamine
receptors so when illicit substances or
amphetamines block those transporters
dopamine accumulates in the synapse
dopamine is highly implicated in the
reward system in your brain
this system trains your brain to learn
that certain actions will pay off with a
desired effect
illicit substances and a fetta means
therefore trick your brain into thinking
it's always accomplishing something the
brain then rewards itself with a sense
of euphoria and success and just as your
brain will increase adenosine receptors
to try to outfox caffeine your brain
will also reduce dopamine receptors if
you do too many stimulants
that's why illicit substances are so
addictive with so little dopamine your
body and brain cry out because they need
that accomplishment feeling it feels
like some action vital to survival is
needed and so you feel like you need it
caffeine withdrawal doesn't tell your
brain you need caffeine in exactly the
same way it just tells you it's tired
and if it's a lazy Sunday afternoon and
you have nothing to do most people are
fine with that you may like being picked
up by caffeine but you can do without it
there are many more specific effects
caffeine has on our bodies and brain and
it would take forever to get through all
of them but there's one we really can
skip that's caffeine's half-life don't
worry
caffeine isn't radioactive we're talking
about caffeine's biological half-life
that's the time it takes for half of a
substance to disappear in a healthy
adult that's about 6 hours
however smoking birth control and some
antidepressants can extend that
half-life to several days but even after
half of the caffeine is metabolized or
removed the other half is still there
and while it may have stopped keeping
you alert and awake it can still impact
the quality of your sleep so let's
assume you have an average physiology
and body weight you don't smoke take
birth control or antidepressants if you
have coffee at 8 a.m.
25% will remain by 8 p.m. if you drink
it in the afternoon it might still be at
half-strength by bedtime
and if it isn't enough to keep you up it
can limit the time you spend in REM
sleep REM sleep or rapid eye movement is
literally the stuff of dreams it's when
our brains reorganize our thoughts to
prepare our minds for the coming day
ahead
depriving yourself of REM sleep can lead
to irritability and a sense that you
didn't rest at all the previous night
you feel tired and you end up needing
more caffeine to get through the day
that's why experts recommend that you
limit caffeine intake to the mornings
they suggest a cutoff time of 2 p.m. for
most adults what does this all mean for
you your morning and your coffee maker
or tea pot by now you should be pretty
confident that caffeine isn't fatal
unless you drink an impossible amount
you can't get addicted to it like other
stimulants at worst it makes you a
little dependent it makes you go to the
bathroom a lot if you drink more than a
few cups and well that's it so if your
caffeine free and wanted to send this
video to a friend who drinks coffee in
the morning and hopes that they quit the
most you can tell them is to have a 2:00
p.m. cutoff time otherwise let the rest
of us have some coffee and tea in the
morning well that's all we have for
caffeine's effect on the human brain and
body what do you think do you think
you're a caffeine addict or have you
sworn off coffee for one reason or
another let us know your thoughts in the
comments below thank you so much for
watching and don't forget to subscribe
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