If you’ve ever missed your morning cup of
joe and been slammed with a killer headache? You are not alone. Withdrawal symptoms from caffeine, from headaches
to fatigue, have been reported in medical literature for
nearly two centuries, although most of the peer-reviewed research
is more recent. Fact of the matter is, caffeine is addictive and affects your brain and nervous system. Doctors consider it to be pretty benign compared to many other addictive substances. But you can become dependent on your daily
coffee fix. Caffeine works by interfering with a molecule
called adenosine. Adenosine is found all over your body.
But in your brain, it helps regulate different
neurotransmitters and can influence how sleepy you feel. By binding to receptors on your brain cells
over the course of a day, adenosine basically tells your brain to step
on the brakes. Because caffeine molecules look pretty darn
similar to adenosine molecules, caffeine can bind to the exact same receptors
and block their function. So caffeine stops adenosine from doing its
thing, while some stimulating neurotransmitters are
still around. That’s why you feel alert and awake. Now, scientists aren’t entirely sure about
the biochemistry behind caffeine withdrawal. Some studies suggest that if you have caffeine
day in and day out, your brain cells start to make more adenosine
receptors to compensate for all the blockage, trying to keep your
brain working normally. So if you take your morning coffee out of
the equation, suddenly there are extra receptors available
for adenosine to bind to, changing neurotransmitter levels and making
you a little sleepier. Regardless of what’s exactly happening on
a molecular level, when the chemistry of your brain changes…
it’s a recipe for withdrawal. Around 12 to 24 hours after quitting caffeine, your brain starts experiencing changes in
blood flow and electrical activity.
Those changes can lead to the headache, drowsiness, and decreased alertness reported by people
who get rid of their morning coffee which can last anywhere from two days to a
couple weeks. Sometimes, withdrawal is also influenced by a psychological phenomenon called expectancy. Basically, if you’re aware that withdrawal
headaches are a thing, you might expect them to happen and that expectation could influence what
symptoms you actually experience. But a 2004 review of over 50 papers from medical
literature found that at least some studies of caffeine
withdrawal were sufficiently designed to keep expectancy
from affecting their results.
So expectations might have some impact on
your symptoms, but caffeine withdrawal definitely has a physiological
impact too. In other words, that daily double shot caramel
macchiato is totally altering your brain chemistry. But, hey, if it helps you concentrate, there doesn’t seem to be too much harm in
it. As long as you’re ok with never stopping! Thanks for asking, and special thanks to all
of our patrons on Patreon! If you want to see more SciShow videos about
caffeine, there’s a link to an early one in the description, and if you just want to keep getting smarter
with us, go to youtube.com/scishow and subscribe!.
