Although exercise is part of the nonpharmacologic treatment of hypertension, studies of older patients have included only a small number of participants and have had inconsistent results. Hypertension in older patients usually is caused by increased peripheral resistance and stiffening of the large arteries. Because these are different mechanisms than those that cause hypertension in younger patients, it is unclear how exercise might affect hypertension in older patients. Older patients also have less muscle mass and more body fat than younger patients, which increases their risk of cardiovascular disease. Exercise has been shown to improve body composition in older patients, but few studies have evaluated its effect on blood pressure. Stewart and colleagues assessed how exercise programs affected blood pressure in older patients.
The randomized controlled trial included men and women 55 to 75 years of age with untreated systolic blood pressures between 130 and 159 mm Hg or diastolic blood pressures between 85 and 99 mm Hg. Participants were randomized to receive combined aerobic and resistance training or usual care. The exercise program consisted of three supervised sessions per week including resistance exercises and 45 minutes of aerobics. The usual care group received advice about physical activity and diet. The following measurements were taken at baseline and at the end of the six-month study: blood pressure; aerobic fitness and strength; body composition (i.e., body mass index; waist circumference; total fat, lean fat, and percent fat mass; and abdominal, visceral, and subcutaneous fat); and arterial stiffness measured by aortofemoral pulse-wave velocity.
The exercise group included 51 participants, and the control group included 53 participants. The exercise group had significantly improved aerobic and strength fitness, increased lean body mass, and decreased general and abdominal obesity. Both groups had decreased blood pressures. The reduction of systolic blood pressure was not significantly different between the two groups, but the exercise group had a significantly greater reduction in diastolic blood pressure compared with the control group. Neither group had a change in aortic stiffness. Improvement in body composition had a significant impact on systolic and diastolic blood pressure reductions.
The authors conclude that a six-month exercise program for older adults with mild hypertension lowered diastolic blood pressures but did not significantly affect systolic blood pressures. Because there was no change in aortic stiffness, older persons may be more resistant to decreasing systolic blood pressures through exercise. The authors add that body composition improvements were associated with decreased blood pressure, which may be why exercise training improves cardiovascular health in older persons.