Study Supports Health Benefits of Moderate Exercise

Harder exercise is better, but even moderate regular exercise can reduce a man’s risk of heart disease--and the exercise doesn’t have to be done in one burst, new research shows.

The findings, from a long, large ongoing project, show a benefit that lasts over decades. And they support federal recommendations that people should do 30 minutes a day of at least moderate exercise, in at least 10-minute segments, most days of the week.

“What we didn’t know is, by adhering to this pattern of exercise, that translated into long-term benefits,” said Howard D. Sesso of Harvard School of Public Health. He worked on two studies that were reported in Circulation, a journal of the American Heart Assn.

Both reports delved into the large pool of data in the long-running Harvard Alumni Health Study. Former Harvard students answered questionnaires about their health and their health habits, including physical activity.

One study looked at the intensity of exercise required to reduce the risk of heart disease, and the amount of time in which the activity should be done. The researchers reviewed data on 7,307 men from 1988 through 1993. The men reported their exercise in as little as 15-minute segments.

As long as the energy expended was the same, it didn’t matter whether the exercise was done in two 15-minute segments or one 30-minute segment, the report said.

Although the Harvard study was structured to look at 15-minute segments, this doesn’t imply the 10-minute segments recommended by the federal government are too short, Sesso said. The federal recommendations were based on valid but more limited studies, he said.

The other study investigated whether the risk of heart disease decreased among people who worked out harder. This time, researchers followed 12,516 men from 1977 through 1993.

The men who did the more vigorous exercise got a better payoff in reduced risk of disease, the study found. The vigorous exercisers, who did such things as running or aerobics, had a risk reduction of up to 20% compared with people who did no vigorous exercise. But those who walked had a reduction of 10%.

The findings support the idea that people who do no exercise should start, and those who are doing a moderate amount could benefit from working harder, said Sesso’s colleague, I-Min Lee.

The new studies fill in some holes in the knowledge that experts had when the Centers for Disease Control and Prevention and the Surgeon General’s Office released their recommendations in the mid-1990s, said Gregory Heath, a physical activity researcher at CDC.

“We had a body of evidence, perhaps not as strong as this longitudinal study,” Heath said. “This confirms that it wasn’t our best guess, but consistent with thinking and the previous data.” Earlier studies were shorter term and found improvements in conditions that could lead to heart disease, such as high blood pressure, he said.

Heath and Sesso hope the findings encourage more people to take up physical activity and thereby get out of the highest risk group for heart disease.

And the findings fit nicely with other work on fitness--the ability of exercisers to get an aerobic benefit from their workouts, said Steve Blair of the Cooper Institute of Aerobics Research in Dallas. But his research indicates there may be a way other than intense workouts to get into the healthy, high-fit group. Long-duration, moderate-intensity exercise may get the same result, he said.

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On the Net:

American Heart Assn.: https://www.americanheart.org

Cooper Institute for Aerobics Research: https://www.cooperinst.org

Office of the Surgeon General: https://www.surgeongeneral.gov/sgoffice.htm

Circulation online: https://circ.ahajournals.org/current.shtml