Caffeine can increase heart disease risk.

Drinking a few extra cups of coffee each day can boost blood pressure, heart rate, and stress levels enough to increase a person's risk of developing heart disease over a lifetime of moderate caffeine consumption, warns James Lane, associate research professor of psychiatry, Duke University, Durham, N.C. In a study of habitual coffee drinkers who wore ambulatory blood-pressure monitors throughout their daily jobs, he found that the equivalent of four to five cups raised blood pressure an average of five points, compared to days when they consumed only one cup. The effect occurred within an hour of consumption, and the subjects' blood pressure remained elevated throughout the day. They also reported higher levels of stress during the day when they received the higher dose of caffeine and showed a corresponding increase in heart rate.

While a five-point increase in blood pressure is not excessive...