Drink Up.(caffeine's side effects)

Byline: --AMY KELLER LAIRD

When you ingest it, caffeine does far more than just give you the jitters. The question is, are we drinking too much coffee for our own good--or not enough? A look at the latest research on caffeine's health-related highs and lows:

CAFFEINE CAN...

...lower your risk of disease. In a new study in the European Journal of Cancer Prevention, testers who drank two to three cups of caffeinated coffee every day were 13 percent less likely to have had nonmelanoma skin cancer than nondrinkers, and those who consumed six or more cups daily were a whopping 30 percent less likely. Additionally, researchers at the Harvard School of Public Health in Boston found that the chance of developing type 2 diabetes--a condition that raises the risk of heart problems--was about 30 percent lower in women who drank four or more cups of caffeinated coffee per day compared with women who consumed fewer.

...make exercise easier. Exercisers who drank 24 ounces of coffee before running, walking, or weight training for one to two hours perceived their exertion as significantly lower than the noncaffeine drinkers did, according to a study at the University of South Carolina. (While some had headaches and muscle tremors, study authors say that just one pre-workout coffee could make exercise seem easier with fewer negative side effects.) And researchers at the University of Illinois at Urbana--Champaign suggest that having one or two caffeinated drinks an hour before exercising (the time it takes for caffeine's effects to peak) can reduce muscle pain and enhance performance. The theory is that caffeine blocks adenosine, a pain-stimulating chemical.

...heighten your concentration. Slugging down 12 ounces of highly caffeinated tea improved testers' speed and accuracy when typing both an understandable paragraph and one consisting of nonsensical words--but only for those who infrequently drank coffee, tea, or cola.

BUT IT CAN ALSO...