Your Brain On: A Caffeine Buzz

We're all about effective studying here at Sciencing. And, let's be honest, many of us have relied on a few cups of coffee to get us through an intensive study session. So if you find yourself reaching for your fave brew to get through exam season, you're far from alone.

And, if you're a fan of caffeine, you already know it can have a significant effect on your body – from feeling more alert during late-night studying to helping you wake up for your exam the next day. But did you ever think about exactly why it's so helpful? Read on to find out.

Caffeine is by far the most well-known active ingredient in coffee, but it's not the only compound in there that affects your body. In fact, a cup of coffee contains more than a thousand compounds, which means your fave brew is probably more complex than you think.

For one, coffee also contains an array of antioxidants – chemicals that neutralize highly reactive compounds called free radicals, which can have a negative effect on your cells. It also contains fat-soluble chemicals, called diterpenes, which can affect your heart health.

How much caffeine – and the amounts of other compounds – found in your cup all depend on the type of beans and the type of roast you choose. In general, light roasts have more caffeine, since less of it gets destroyed during the roasting process, while dark roasts and espresso have less caffeine.

To understand how caffeine keeps you awake, you need to understand how sleep signals work in your brain. One way your brain boosts sleepiness is through releasing a chemical called adenosine. It can get a little complex, but here's the gist of it: As more adenosine compounds attach to special proteins called receptors, the sleepier you get. And, eventually, your adenosine levels get high enough that you're ready to hit the sheets.

At least, if you didn't have caffeine. See, caffeine has a chemical structure that's kinda similar to adenosine. It's close enough that it's able to block adenosine from binding to its receptors – but not so similar that it also induces sleepy feelings.

The end result? Caffeine suppresses the "sleep" signals in your brain, so you're less tired – and more ready to study for hours.

Instant alertness sounds great, right? And it is – in moderation.

But you still need to sleep.

And one of the downsides of caffeine is that it can feel harder to sleep, even when you want to. Excess caffeine consumption is linked to a (temporary) high heart rate and higher blood pressure, which means it can feel harder to relax. And drinking too much coffee, or drinking it too close to bedtime, can cause insomnia.

Over time, sleep deprivation caused by caffeine can make you feel tired, anxious and keep you from concentrating properly. So drink coffee in moderation. Try sticking to one cup of coffee in the morning, and avoiding it before bedtime. And if you do need a caffeine buzz to get through late-night studying, make sure to get a good night's sleep the next night.