Caffeine and hypertension: a bad brew?
Bong Hee Sung, a hypertension researcher at the State University of New York at Buffalo, measured the cardiovascular effects of caffeine and exercise on men with normal and elevated blood pressure. The results of her study suggest that caffeine and exercise in combination may exert a more deleterious effect on hypertensives than on people with normal blood pressure.
Sung measured the heart rate and blood pressure of men who exercised after ingesting either a placebo or the caffeine equivalent of three cups of coffee. She found that hypertensives experienced much greater increases in heart rate on caffeine than on placebo, whereas the heart rates of men with normal blood pressure went up the same amount regardless of which substance they downed.
Systolic blood pressure, which reflects the force exerted by the contracting heart, rose in both groups when they exercised after taking caffeine. However, only the hypertensives showed a rise in diastolic pressure -- the pressure on the blood vessels when the heart muscles are relaxed -- when exercising under the influence of caffeine.
The increases in systolic and diastolic blood pressures attributable to caffeine averaged about 10 percent. Sung argues that such incremental boosts increase the damage done to the cardiovascular systems of people who already have higher-than-normal blood pressure.
"Until further studies show that antihypertension medications protect [patients] from the effects of caffeine, I think we have to warn [them] to abstain from caffeine if they can," Sung advises.
Sung's work, which focuses on the cardiovascular consequences of caffeine and exercise on hypertensive men, is part of a larger, federally funded study assessing the effects of caffeine and stress. Sung now plans to investigate whether antihypertension medications cancel out caffeine's influence on blood pressure.
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|Title Annotation:||coffee-drinking and exercise should not be combined in hypertensive people|
|Article Type:||Brief Article|
|Date:||Nov 21, 1992|
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