And the hypertensive effects of coffee seem to depend on ingredients other than caffeine.

Coffee does raise blood pressure in people who are not used to it but not in regular coffee drinkers youngsters appear more sensitive to coffee. The study helps explain why earlier investigations produced such variable results. It did not raise blood caffeine levels, but it boosted the average systolic blood pressure of the nondrinkers by 12 mm Hg, virtually as much as the high-test brew. The decaffeinated espresso proved the point. Caffeine gets the blame for raising blood pressure, but the disparity between espresso and pure caffeine suggests there is more to the story. Moreover, the coffee drinkers and the nondrinkers responded similarly to intravenous caffeine.Ī simple cup of coffee contains hundreds of complex substances. But the straight-up caffeine had a much smaller effect on blood pressure than the espresso, boosting systolic blood pressure by an average of just 6 mm Hg. Indeed, blood caffeine levels rose to the same degree after the caffeine injections and the espresso. In fact, espresso did not boost the pressures of habitual coffee drinkers, though it raised systolic pressure readings on average by 13 mm Hg and diastolic pressures by 7 mm Hg in subjects who were not coffee drinkers.Įspresso is strong stuff, but an intravenous slug of caffeine should be even more potent. But although blood caffeine levels rose to a similar degree in all the subjects, not all experienced a rise in blood pressure. The researchers monitored each volunteer's blood pressure, heart rate, and sympathetic nervous system under four conditions: before and after drinking a triple espresso, before and after drinking a decaffeinated triple espresso, before and after receiving 250 mg of caffeine by intravenous injection, and before and after an intravenous placebo (salt solution).Ī triple espresso causes quite a jolt, and it did jolt blood pressure readings. None of the subjects had high blood pressure or hypertensive parents, and all were healthy nonsmokers only six were habitual coffee drinkers. 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.Īfter 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. It's standard advice based on the notion that caffeine raises the blood pressure enough to interfere with an accurate measurement.

Most doctors advise people to avoid coffee (and other sources of caffeine) before they have their blood pressures checked. Is coffee bad for high blood pressure? A fresh look The circulatory effects of coffee are more complex than they seem, and an interesting study can help you filter out fact from fiction. But many people are sensitive to even one cup of coffee, making them feel jittery or interfering with sleep. Some of coffee's negative press seems to depend on the widespread belief that anything that tastes so good must be bad for you.īut there is a serious side to the argument: Coffee stimulates the nervous system, increasing alertness. 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. Coffee has been part of the human diet for about 1,000 years.

Caffeine and blood pressure