By Markham Heid
September 07, 2014
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Colleges and universities are back in session. That means millions of students nationwide are going to be reaching for their favorite study-time stimulant and morning eye-opener. (And no, it's not Adderall.)

Coffee is still king of the late-night cram session and early morning course schedule. Of course, the drink helps you feel lucid and sharp. (More on that in a minute.) But coffee's effects on your brain don't end there. From your memory to your mood, coffee canoodles with your brain and its chemicals in interesting ways.

How Coffee Perks You Up

Everyone knows caffeine is the stuff in your coffee that keeps you awake and alert-at least for a while. How does it work? It plugs neurochemical receptors in your brain that would normally light up in response to the types of hormones that make you feel tired, shows a study from the U.S. and Italy.

At the same time, by plugging those sleep-triggering receptors, caffeine allows energizing brain chemicals like glutamate and dopamine to circulate more freely. When you feel a buzz from your triple espresso, it's those two chemicals-not caffeine-that are amping you up, research shows. So think of caffeine as the DJ at a wild party; it's hanging out off to the side of things and keeping the party going so your brain's good-time chemicals can rock out.

Coffee, Your Memory, and More

A study from Johns Hopkins University found swallowing the amount of caffeine in one or two cups of coffee boosts a person's memory for new information by roughly 10 percent. How? Probably in the same ways caffeine keeps you awake and sharp, explains Michael Yassa, Ph.D., co-author of the Johns Hopkins study. Yassa says caffeine might help ramp up the activity of those brain chemicals involved in memory storage.

There's also some evidence that coffee may strengthen the sense-based information your brain collects. Many studies dating back to the 1970s have found that the amount of caffeine in one to four cups of coffee can heighten your brain's sensitivity to light and color, as well as sound. This may contribute to caffeine's memory boosting abilities, the studies hint. (If you're brain is better at absorbing sensory info, your memories will be sharper, the data suggest.)

Dozens and dozens of research papers have also tied coffee and caffeine to improved decision making, focus, quicker information recall, longer and sharper attention span, and many more brain benefits. Some newer research has even linked coffee consumption to lower rates of age-related brain diseases like dementia.

Coffee and Your Mood

Coffee may help ward off the blues (the serious kind linked to depression). Several research papers have shown the caffeine in coffee may increase the amount and activity of the brain chemical serotonin. Low levels of serotonin have been linked to depression. And this serotonin boost may help explain why a study from the U.K. found people who drink coffee in the morning feel friendlier, happier, and more content.

On the other hand, too much caffeine can heighten your feelings of tension and anxiety, shows a study from Singapore. It can also crank up your stress levels if you're already feeling frazzled. "Too much" depends on how much caffeine your system is used to dealing with, the authors say. So if you're a two-cup-a-day person, you'd probably have to drink double that amount to feel these negative mood effects. At the same time, if you don't drink much coffee, smaller doses of caffeine could trigger anxious feelings, the authors say.

The Bad News

Multiple studies have shown caffeine is both habit- and tolerance-forming. That means if your brain gets used to your drinking coffee, you may not be able to think clearly or feel sharp if you abandon your brew. You may also have to drink more and more coffee to feel like yourself, research suggests. But the good news? For most people, there are few downsides to drinking up to 24 ounces of coffee a day, concludes a massive review study from Oregon State University.


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