" In this study, "moderate" translated to sustained exercise for about an hour, three times a week. Researchers say that people's concerns stem from the fact that during each workout, blood pressure can on average rise from 40 millimeters to 60 millimeters of mercury. The Hopkins study is believed to be the first to evaluate the effects of exercise on the heart's ability to function, to pump and to fill up with blood. "

" "While having high blood pressure at rest is a well-established risk factor for heart problems, older people should not fear the effects of moderate exercise on the heart, despite short-term bump-ups in blood pressure during their workout," says lead study investigator and exercise physiologist Kerry Stewart, Ed.D., a professor of medicine and director of clinical and research exercise physiology at The Johns Hopkins University School of Medicine and its Heart Institute. "Exercise is a highly effective means of increasing the heart's efficiency and reducing body fat, factors that may ward off future health problems, such as heart disease and diabetes." "

" A report on the Hopkins study, published in the July issue of the journal Heart, showed that after six months of aerobic exercise on a treadmill, bicycle or stepper, plus weightlifting, participants showed no overall ill effects in 11 measures of diastolic heart function, when the organ's main chamber fills with blood between beats. They also found that exercise produced no increase in eight measures of heart size, including left ventricular mass and wall thickness. In contrast, a long-term effect of hypertension, even when the body is relaxed, is hypertrophy, an enlargement of the heart that eventually stiffens and weakens the muscle. "

" Not only were there no ill effects sustained, despite periodic increases in blood pressure during the workout, Stewart and his team reported, but results also suggest that the exercise producing these effects benefited the hearts of those who made the most gains in physical fitness and for those who lost the most abdominal fat. "

" Researchers found, for example, that each single point gain in aerobic fitness (of 1 milliliter per kilogram per minute), as measured by peak oxygen uptake by the blood during exercise, translated to a 1.5 percent improvement in one key measure (the E/A ratio), used to measure diastolic heart function. In addition, every 10-point decrease in abdominal fat (of 1 square centimeter) translated to a 1.2 percent gain in a second key measure (the Em/Am ratio). "

" And, researchers say, unlike the increased heart size that results from high blood pressure, any increase in heart size observed in the active group was similar to what athletes experience when their hearts get bigger and stronger, not stiff. "

" They describe the activity-related form as physiological hypertrophy as opposed to the former kind, which they call pathological hypertrophy. "

" For a six-month period, the Hopkins team assessed the benefits of a supervised program of exercise training in a group of 104 older men and women, measuring heart function, and body fitness and fat levels at the start and end of the study. All of the participants were in general good health except for untreated, mild hypertension. Half were randomly placed in a widely recommended moderate exercise program while the rest maintained their usual physical routine and diet. "

" The active group participated in a supervised series of exercises for 60 minutes, three times per week. The combination of exercises was designed to work all major muscle groups, including the heart, with substantial improvements observed in active participants' body fat, and muscle and fitness
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