Caffeine

Caffeine is a stimulant found in coffee, tea and soda and may help ward off sleepiness. It is a commonly used drug that has been shown to enhance vigilance, increase alertness and improve mood and reaction time. It is generally considered safe for most people to consume a moderate amount of caffeine, out 300 milligrams, or the amount in two cups of coffee.

However, caffeine affects everyone a little differently and a lot depends on how much you're used to consuming. The more caffeine you drink, the more of a "tolerance" you develop. If you typically drink several cups of coffee each day, you would have to drink even more than that in order to feel caffeine's effects like keeping you alert. The best strategy for both your health and your grades may then be to only drink a cup of coffee or soda now and then when your concentration could use a boost as opposed to regularly.

Are there any side effects of having too much caffeine?

There are side effects of consuming caffeine. First of all, caffeine temporarily stimulates the central nervous and cardiovascular systems, increasing heart rate and blood pressure, stimulating muscles and increasing urination. Secondly, caffeine at doses higher than someone is accustomed to may cause jitters, anxiety and diarrhea. In addition, someone who consumes caffeine regularly may experience withdrawal symptoms, including jitters and headache, when caffeine is suddenly decreased. But because people have different tolerances to caffeine and some people are simply more sensitive to it, it is difficult to quantify the number of milligrams at which point any side effects will occur.

Caffeine can also increase calcium losses, but moderate amounts (300 mg per day) seem to have little influence on bone health. The Recommended Dietary Allowance (RDA) for calcium is 1000 mg and if you choose a 12-ounce latte with skim milk, you'll get 450 mg of calcium towards your daily total.

The Bottom Line

Caffeine has been shown to improve concentration and alertness the most in people who don't regularly consume it. Therefore, unless your doctor tells you otherwise, it is generally safe to consume a moderate amount of caffeine, less than 300 mg per day. If you haven't always been a latte lover and suddenly begin to consume a lot of caffeine during the week of exams, you may find yourself jittery, nervous and running to the bathroom.