High blood pressure is a modifiable risk factor for cardiovascular disease. Studies have shown that elevated blood pressure can lead to stroke, congestive heart failure, coronary heart disease, and renal disease. Because lowering blood pressure, even by a small amount, reduces cardiovascular disease morbidity and mortality, physicians should use all modalities to accomplish a reduction in blood pressure. A sedentary lifestyle is associated with increased blood pressure and is a major risk factor for cardiovascular disease. Several studies have demonstrated that physical activity reduces blood pressure in normotensive and hypertensive persons, regardless of weight loss. Whelton and associates collected data from clinical trials to clarify the effect of aerobic exercise on blood pressure.

The authors performed a MEDLINE search for appropriate trials published from 1966 to September 2001 in English-language journals and including adults in randomized intervention and controlled trials. The only permissible difference between the treatment and control groups was aerobic physical activity. Follow-up had to last at least two weeks.

Of the 54 trials included in this study (involving 2,419 persons), 53 trials included data on systolic blood pressure and 50 trials included data on diastolic blood pressure. The trials varied in length from three weeks to two years, with a median duration of 12 weeks. Statistically significant reductions in systolic blood pressure occurred in 20 of the 53 trials, and significant reductions in diastolic blood pressure occurred in 16 of 50 trials. The combined decrease in systolic and diastolic blood pressure with aerobic exercise was 3.84 mm Hg and 2.58 mm Hg, respectively. This drop increased in studies that did not require supervised aerobic exercise.

Reduced blood pressure was observed in all subgroups, although black and Asian participants had significantly greater reductions in systolic and diastolic blood pressures, respectively, compared with white participants. Studies with longer follow-up periods and more participants demonstrated a smaller blood pressure drop among the intervention groups. There was no difference in blood pressure changes among trials with normal or overweight participants or between participants who lost or did not lose weight.

The authors conclude that aerobic exercise has a significant blood pressure-lowering effect; this effect is consistent among patients from various ethnic groups and with different body weights, and is independent of weight loss. The decreased effectiveness of aerobic exercise in trials with longer follow-up was probably caused by poor program adherence, especially when the exercise was un supervised. The type of aerobic exercise involved did not alter the findings. Aerobic exercise can be an important aspect of strategies to prevent and treat high blood pressure.