CHICAGO (AP) - Moderate physical activity is good for preventing heart disease, but revving up the pace may be better - especially if combined with weight-training, a Harvard study of more than 40,000 men suggests.
Researchers have debated whether pace makes a significant difference in protecting the heart, but the new study found that men who exercised at high intensity were 17 percent less likely to develop heart disease than those who did low-intensity exercise.
High-intensity exercise includes running or jogging at 6 mph, while low-intensity activities include walking at a pace of about 2 mph.
Researchers also have debated whether weight-training has a big impact on the heart, since it does not give the heart and lungs the kind of workout they get from aerobic activities such as brisk walking or running for at least 20 minutes.
But in the Harvard School of Public Health study, men who engaged in weight training for 30 minutes or more weekly had a 23 percent lower risk of heart disease than men who did not pump iron. The researchers said the benefits may result in part from reductions in blood pressure and body fat achieved through weight training.
Given the independent results from weight training, the researchers theorized that adding weight training to a high-intensity exercise program would reap even greater benefits.
The study appears in Wednesday's Journal of the American Medical Association. It is based on medical records and questionnaires given periodically to 44,452 health professionals from 1986 to 1998. Participants were ages 40 to 75 at the outset.
Heart disease was ultimately diagnosed in 1,700 participants.
Men who ran for an hour or more weekly at 6 mph or more were 42 percent less likely to develop heart disease than non-runners. Men who did brisk walking at a moderate pace of at least 3 mph for at least a half hour daily were 18 percent less likely to develop heart disease than those who did not. There were no significant heart benefits found from low-intensity walking.
"The more exercise you do and the higher intensity seems to be better with regard to cardiovascular protection," said Dr. Gerald Fletcher, an American Heart Association spokesman and cardiologist at the Mayo Clinic in Jacksonville, Fla.
He said the findings correspond with AHA guidelines, which recommend aerobic exercise at least six days a week and weight-training two or three times weekly.
But Fletcher said the results should not discourage couch-potatoes who may be contemplating starting an exercise program.
"A little is better than sitting in front of the television," he said.
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