Moderate exercise alone has little effect on systolic blood pressure - the upper number in a standard reading - in older adults, new research suggests.

“Older people should still be encouraged to exercise because it produces numerous health benefits, but their expectations need to be modified about how much good the exercise alone will do for reducing systolic blood pressure,” lead author Dr. Kerry J. Stewart, from the Johns Hopkins School of Medicine in Baltimore, said in a statement.

The findings, which appear in the Archives of Internal Medicine, are based on a study of 104 adults between 55 and 75 years old with untreated high blood pressure. The subjects were randomly selected to participate in 6 months of aerobic and resistance training or no exercise training.

Compared with the non-exercise group, the exercise group showed significant improvements in aerobic and strength fitness, increased lean body mass, and reduced general and abdominal Obesity. The exercise group also had significantly greater drops in systolic and diastolic blood pressure, the lower number on a standard reading.

Still, compared with starting blood pressures, only the exercise group’s diastolic blood pressure fell significantly. Their systolic blood pressure was relatively resistant to the beneficial effects of exercise.

Further analysis showed that 8 and 17 percent of the reductions in systolic and diastolic pressures, respectively, were due to body composition improvements, such as a drop in body fat, the authors note.

“These findings suggest that changes in body composition seem to be an important pathway by which exercise training improves cardiovascular health in older men and women,” the researchers note.

SOURCE: Archives of Internal Medicine, April 11, 2005.