Coffee and your blood pressure

Coffee has been part of the human diet for about 1,000 years. During much of that time, it has stimulated controversy — and in the age of Starbucks, the dispute has blossomed from a tempest in a coffee pot to grounds for serious debate. Some of coffee's negative press seems to depend on the widespread belief that anything that tastes so good must be bad for you. But there is a serious side to the argument: Coffee stimulates the nervous system, increasing alertness but interfering with sleep. Acting as a diuretic, it stimulates the flow of urine. And it stimulates the cardiovascular system, boosting the heart rate and raising blood pressure. But the circulatory effects of coffee are more complex than they seem, and an interesting study can help you filter out fact from fiction.

A fresh look

Most doctors advise people to avoid coffee (and other sources of caffeine) before they have their blood pressures checked. It's standard advice based on the notion that caffeine raises the blood pressure enough to interfere with an accurate measurement. But medical research has been murky; some studies support a link between coffee drinking and hypertension, but others do not — and a 1987 Italian investigation suggests that coffee may even help to reduce blood pressure.

After poring over these divergent views, scientists from Switzerland and the United States decided to take a fresh look by performing detailed studies on 15 volunteers. None of the subjects had high blood pressure or hypertensive parents, and all were healthy nonsmokers; only six were habitual coffee drinkers.

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