More Frequent Exercise Is Best, Researchers Say

Shorter, more frequent, rather than longer, less often exercise sessions are better for the heart, suggests a 12-year study of the exercise habits of more than 22,000 male physicians.

“The more frequent the exercise, the lower the risk of heart attack and death from heart disease,” says Dr. Claudia Chae, a cardiologist and research fellow at Brigham and Women’s Hospital in Boston. “Duration doesn’t have as much of an effect, with no significant differences in benefit among men who worked out for 11 to 24 minutes and those who exercised longer.”

Chae’s conclusions are based on data from the Physicians’ Health Study, which looks at the health and behavior of 22,071 male physicians who were 40 to 84 years old when the study began in the mid-1980s. She reported her findings at last month’s annual meeting of the American Heart Assn. and has been amazed at the strong media attention her study aroused.

“People seem surprised that you can get a great deal of benefit from relatively short bouts of exercise,” she says. “Everyone wants to know how little [exercise] they can get away with.”

So what’s the least amount of physical activity you can do for heart health?

“Our study suggests that exercising vigorously at least one to two times per week for at least 11 to 24 minutes per session can get you a pretty significant risk reduction,” she says. “If you can increase the frequency, you can get even more benefit.”

For example, the risk of heart attack decreased by 36% among those who exercised vigorously one to two times a week, 38% among those who exercised three to four times a week, and 46% among men who exercised five or more times weekly, Chae’s study found.

But there’s a catch: The Physicians’ Health Study looks only at vigorous exercise, defined as exercise that works up a sweat. And judging from the small fraction of adults who exercise strenuously, most Americans don’t like to sweat. Only 15% of American adults engage in vigorous physical activity for at least 20 minutes, three times a week, notes Carl Caspersen, a physical activity epidemiologist at the federal Centers for Disease Control and Prevention in Atlanta.

In general, the more intense the workout, the less time necessary to achieve a specific goal.

“Say your goal is to burn 200 calories,” says exercise physiologist Stephen Farrell of the Cooper Institute for Aerobics Research in Dallas. “You could do 40 minutes of a moderate-intensity activity like walking or just 20 minutes of a higher-intensity activity like jogging.”

Neither option is better than the other. They are both good choices, depending on your preferences, physical condition and time.

The U.S. Surgeon General’s Report on Physical Activity and Health, released last year, gave people many exercise options by emphasizing the amount rather than the intensity of physical activity. Its recommendation: Burn 150 calories per day in physical activity such as walking or raking leaves for 30 minutes, running for 15 minutes or washing and waxing a car for 45 to 60 minutes.

For a free copy of the brochure “Fitting Fitness In, Even When You’re Pressed for Time,” send a self-addressed, stamped business-size envelope to the American College of Sports Medicine, c / o Fitting Fitness In, P.O. Box 1440, Indianapolis, IN 46206-1440.

* Fitness runs Mondays in Health.