Does coffee increase blood pressure?

Coffee drinking has long been associated with increased blood pressure. At John Hopkins University, researchers have followed up with more than 1000 former medical students for 33 years. These students were all white males with an average age of 27. The participants would report the amount of coffee drank each day as well as their blood pressure. Among them, 82% have reported drinking one cup of coffee or more each day.

The findings show that those who reported drinking at least one cup of coffee a day display a heightened systolic blood pressure of 0.19 mm Hg more than those who do not. Also, their diastolic pressure is raised by 0.27 mm Hg. Coffee drinkers also have a greater incidence of hypertension than non-coffee drinkers.

The incidence rate of hypertension increases among those who consume five or more cups a day. Although this fact may be alarming on its own, its significance is highly reduced when the researchers adjusted the results for other hypertension risk factors such as genetics, smoking, alcohol intake and physical activity. The final readings show that the association between coffee drinking and hypertension is insignificant.

It is long-thought that caffeine causes the blood pressure increases among coffee-drinkers; however this change is quickly adapted to by the human body. These findings show that drinking coffee is linked to small increases in blood pressure, but plays only a minor role in the development of hypertension.

SOURCE: Archives of Internal Medicine, 2002;162:657-662