Study: Easier workouts may still help older exercisers' hearts

Wed Mar 19, 8:11 PM ET

By IRA DREYFUSS, Associated Press Writer

WASHINGTON - For older exercisers, effort counts.

At least that's what a large Harvard study of heart disease in older men showed.

It found that those who thought their workouts were hard had a lower risk of coronary heart disease, even though the amount of energy they burned was below minimum federal guidelines.

"Are they getting any benefit? The bottom line is yes, they are," said researcher I-Min Lee of the Harvard School of Public Health. Even though the study involved only men, Lee said the study could be applied to women as well.

The study suggests that older people may be able to do less exercise and get heart health benefits — provided they feel they are working hard. The findings were published in February in the American Heart Association journal Circulation.

Researchers looked at 7,337 men in the long-running Harvard Alumni Health study. The scientists examined questionnaires from 1988-95 from men who had an average age of 66. In the study period, 551 developed coronary heart disease, a narrowing of the small blood vessels that feed the heart.

In the questionnaires, the alumni listed their physical activities. The researchers then estimated how much energy the men probably used in doing them. Those results were tallied in METs — multiples of resting metabolic rate, or the amount of energy a person uses just to sit quietly.

Sitting quietly is 1 MET; walking briskly would be about 4 METs, and jogging a mile (1.6 kilometer) in 12 minutes would be 6 METs.

The men rated the difficulty levels of the exercise on a 1-10 scale with 10 being the most difficult.

Researchers focused on the men whose workouts were at or below 3 METs, because the 3-to-6 MET range is the minimum energy expenditure that federal exercise recommendations consider healthful, Lee said.

Looking at this low-MET group, the scientists compared men whose activities felt hard to those who felt their activities were easy.

The ones who rated their intensity at 5 on the 10-point scale had a 31 percent lower rate of coronary heart disease than did men who rated their intensity at .5.

"The ones who felt they were exercising hard did better than ones who felt nothing," said Lee.

The results make sense because the cardiovascular system is sensitive to increased effort, said scientist William Haskell of Stanford University, who was not part of the research team.

If a person's fitness level is low at the start, then a strong effort can create a training effect, he said. Training that feels hard can be enough to increase the heart's ability to pump more blood with each beat, and also could reduce cholesterol levels, he said.

Lee said she did the study to see if people who do less than the METs targeted in the recommendations would still get some benefit. However, neither she nor Haskell believe people should try to get by on less. For one thing, a higher metabolic rate means more calories are burned — and weight can be lost.

But current MET standards don't adequately account for the slowing of metabolism that comes with age, Lee said. The guidelines are based on the bodies of younger adults who have higher metabolic rates that could run at 3 to 6 METs in moderate exercise, she said.

Lee said older people would feel they are working just as hard at lower METs.

Although the science behind the exercise recommendations is based in part on METs, the guidelines themselves are written in language based on ratings of perceived exertion. Because people can't keep track of their METs, the guidelines call for at least moderate exercise for a minimum of 30 minutes on most days of the week.

Lee would not change the wording. The recommendations are easy to understand and widely applicable — and even older exercisers who won't reach 3 to 6 METs still could find their efforts rewarded, she said.

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