Coffee: what is it doing to you?

Coffee is a societal norm these days, there is a coffee shop on most corners and it is very common to see people walking their prams/dogs with the old cardboard cup in hand! You practically name yourself a social oddity if you don’t drink coffee or tea these days.

As a caffiene quitter, I have been free of the drug for a little while now (and loving the freedom and the balance in my awake/tired cycles), but recenelty I did a long 9 hour drive by myself in the late afternoon.  About 3 hours in, I though I was in major trouble and pulled over the get a coffee.  It did the trick, I was buzzing!!  But noticed the next day I was incredibly tired, so drowsy and could barely keep my eyes open and craving another coffee to wake me up.  I am no longer addicted to coffee, so I knew I wouldn’t get the withdrawals from just 1 cup, but it got me thinking about how it actually works.

Here is how:

Throughout the day your body produces a chemical called adenosine and your nervous system has special receptors that monitor your adenosine levels.  As the the day goes on, more and more adenonsine passes through the receptors and makes you sleepy at night. Caffeine is the same shape and size as adenosine and your receptors can’t tell the difference.  But rather than passes through the receptor, caffeine attaches itself to the receptor and blocks the adenosine from entering and stops you from getting tired.

BUT it doesn’t last forever.  It takes about 4 cups of coffee to block the receptors in half of your brain, and with them blocked up, the adenosine has nowhere to go, so it just builds up.  When the caffeine does wear off, the extra adenosine rushes through your receptors and it takes a long time for your body to process the flow, which leaves you even groggier than before the caffeine.  Leaving you craving your next cup of coffee….

Now, if you are drinking coffee or tea or caffeinated drinks every day, thenthe brain’s chemistry can actually change over time.  The brain cells grow more adenosine receptors, which is the brain’s attempt to maintain balance in the face of a constant onslaught of caffeine, with its adenosine receptors so regularly blocked. This explains why regular coffee drinkers build up a tolerance over time—because you have more adenosine receptors, it takes more caffeine to block a significant proportion of them and achieve the desired effect.

This also explains why suddenly giving up caffeine can result in a range of withdrawal effects. The principle is that your brain is used to operating in one set of conditions (with additional adenosine receptors) that are dependent on regular doses of caffeine. Suddenly, without the drug, the altered brain chemistry causes all sorts of problems, including the dreaded caffeine withdrawal headache, nausea, leg pains, and more…


Catherine Craig
Catherine Craig

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