Study Says Moderate Caffeine Boosts Heart Disease Potential

A Duke University researcher says drinking a few extra mugs of coffee every day can boost blood pressure, heart rate and stress levels enough to increase the risk of developing heart disease over a lifetime of moderate caffeine consumption.

Nineteen coffee drinkers wore blood-pressure monitors during their daily activities. James Lane, an associate research professor of psychiatry found that the equivalent of four to five cups raised blood pressure an average of five points, compared to days when they had only one cup. The effect occurred within an hour, and the blood pressure remained elevated all day.

Lane says that while a five-point increase is not excessive, it can have significant clinical implications over time. A review of nine major studies of blood pressure and cardiovascular disease risk showed that a five point difference was associated with at least a 34 percent hike in the incidence of stroke and a 21 percent increase in coronary heart disease.

"The relevant message here is that the more caffeine you consume during the day in coffee, tea or soft drinks, the higher your blood pressure is likely to be," Lane said.

Researchers have long known that caffeine boosts blood pressure, but such studies were conducted in lab settings under controlled conditions.

Lane said his study is the among the first to analyze blood pressure levels at 15-minute intervals under normal daily circumstances, while the subjects were exposed to a range of moods and activities, from sitting to standing to walking.