Coffee is the most popular drink in many parts of the world, and it’s surprising how this hot, dark, nectar of the gods affects our biology.
The main biologically active ingredient in coffee is the stimulant caffeine. The stimulant properties of caffeine mean you can count on a cup of coffee to wake you up. In fact, coffee is the most commonly used psychoactive drug in the world. It seems to work as a stimulant, at least in part, by blocking adenosine, which promotes sleep, from binding to its receptor.
Caffeine acts as a molecular mimic, filling and blocking the adenosine receptor, preventing the body’s natural ability to be able a rest when it’s tired.
This blocking is also the reason why too much coffee can leave you feeling jittery or sleepless. You can only postpone fatigue for so long before the body’s regulatory systems begin to fail, leading to simple things like the jitters, but also more serious effects like anxiety or insomnia.