A commitment of only 60 to 90 minutes of aerobic exercise per week is optimal to reduce systolic and diastolic levels in people with essential hypertension, according to an article in the August issue of the American Journal of Hypertension. Japanese researchers found that such a weekly aerobic exercise regimen reduced systolic blood pressure by an average of 12 mm Hg and diastolic blood pressure by 8 mm Hg.

"This study confirms the importance of exercise," says Michael A. Weber, MD, an editor of the American Journal of Hypertension. "The investigators found a person does not have to spend great amounts of time working out. They determined that a modest time investment in exercise pays a dividend of reduced blood pressure. This finding means many people who are not dedicated exercisers should now be persuaded to make this modest commitment to their health."

The researchers evaluated dose response to aerobic exercise in 207 people (144 men and 63 women) who, except for hypertension, were healthy. The participants were divided into five groups based on level (dose) of exercise: sedentary controls (39 people), weekly exercise of 30 to 60 minutes (55 people), 61 to 90 minutes (54 people), 91 to120 minutes (21 people), and more than 120 minutes (38 people).

The regimens were conducted for 8 weeks at each participant’s nearest fitness club under the supervision of a personal trainer. Each exercise session consisted of a brief warm-up period, aerobic exercise (such as walking, jogging, cycle ergometer, or swimming), and conditioning work (sit-ups and stretches). Intensity of aerobic exercise was
standardized at 50 percent of maximum oxygen consumption.

The researchers found systolic and diastolic blood pressure did not change in the sedentary control group. The exercise groups demonstrated significant reductions in both systolic and diastolic blood pressure.

"The magnitude of reductions in systolic blood pressure was greater in the
61 to 90 minutes per week group compared with the 30 to 60 minutes per week
group," the authors wrote. "There were no greater reductions in systolic blood
pressure with further increases in exercise volume."

There was no association between weekly exercise frequency and effect in lowering blood pressure: "Our present results indicate that the amount of exercise required to
reduce blood pressure in the hypertension population may be considerably
lower than the current recommendation for physical activity," the investigators said. The current recommendation is 30 minutes a day of exercise.

"More important, the volume of exercise required to reduce blood pressure may be relatively small that should be reasonably attainable by this high-risk population," they added. "We should emphasize that our present results should not be viewed as a message against encouraging people to exercise more on a daily basis.

"It is important to note that depending on the cardiovascular risk factor, the dose of exercise required to induce health benefits seems to be different," the investigators concluded. "Our present results indicate that in previously sedentary hypertensive subjects, clinically significant decreases in blood pressure can be achieved with relatively modest increases in physical activity above sedentary levels."