Crazy things caffeine does to your body


Wakes you up

Your brain produces a molecule called adenosine, which binds to receptors in your brain and slows down neural activity: it's a natural process that's thought to help you get to sleep at night but often makes you drowsy during the day. When you knock back that cup of joe in the morning, the caffeine is quickly absorbed into the blood and makes its way to the brain. There, it makes like a bad house guest and plops itself down in adenosine's favorite armchair. But where adenosine makes you tired, caffeine doesn't, and so every brain receptor that binds with caffeine is one that can't make you tired. In other words, caffeine doesn't have an agenda, and it called shotgun.

Makes you poop

Caffeine has long been known to affect muscles, increasing activity and speeding contractions. And while that's useful in an athletic sense, it's useful in a more sedentary sense when applied to the intestines. Another theory is that caffeine increases the production of a hormone that stimulates the colon, which in turn stimulates the reading of newspapers in a locked room. But since researchers have reproduced the effect using decaffeinated coffee, that's one theory that could probably use more fiber.

Gives you energy


Improved energy use and lower exertion

The next useful side effect of caffeine consumption is achieved as a result of the increased blood flow. As the heart beats faster, more blood moves through your body and through your lungs, leading to increased oxygenation, which is of crucial importance during sustained exertion and allows the muscles to operate more efficiently and with less effort. Caffeine also stimulates the metabolism, which means you're burning more calories when you're doing nothing. Don't get your hopes up for a weight loss shortcut though, because potential caffeine-based weight loss programs are a shaky proposition.

Helps you concentrate

As well as stealing adenosine's seat, caffeine is something of an enabler to serotonin, dopamine, and other neurotransmitters that help the brain talk to itself. Norepinephrine is another neurotransmitter that's produced in various parts of the body, and is especially good at speeding up brain function and improving concentration and memory retrieval. It also improves muscle function and efficiency. All very useful if you're running from a sabre toothed tiger, as well as for getting that report finished by the deadline.

Relieves headaches


Addiction and withdrawal


Bad stomach



Although it can take as little as 15 minutes for caffeine to get to work after entering your body, it can take as long as six hours for your body to remove it again. And for all that time, you're under its influence. That's great if you take it at the beginning of a long shift, but not so good if you're planning sleep any time soon. Because with all those extra hormones and neurotransmitters floating around your system, you're unlikely to keep your eyes closed, and when you do finally fall asleep, it messes with your sleep patterns—resulting in less time spent in REM sleep. All this adds up to more fatigue, which equals more coffee, and the whole thing starts again. Caffeine sure picked an effective marketing strategy.


If you've ever wondered what it's like to spend a year on the international space station, caffeine holds the answer…at least to one of the less pleasant side effects of space travel. That's because one of the things shared by astronauts and people who consume large quantities of caffeine is a loss of bone density. The people most at risk of this are the elderly of course, but it's definitely a possibility for someone looking to be extra authentic for their astronaut cosplay.