Exercising for Fun Better for the Heart

Work-related physical strain, however, has the opposite effect

WEDNESDAY, May 28, 2003 (HealthDayNews) -- Engaging in exercise in your leisure hours can decrease your risk of a heart attack by as much as 60 percent, a German study has found.

If your exercise comes in the form of physical strain at work, however, the opposite is true -- your risk of heart disease goes up.

These are among the findings of a study at the University of Ulm Medical Center in Germany, that studied 781 middle-aged men and women, 312 of whom had heart disease.

"The study provides additional evidence that leisure time physical activity (LTPA), but not work-related physical strain (WRPS) is associated with a decreased risk of coronary heart disease," the authors write.

The findings appear in the May 26 issue of the Archives of Internal Medicine.

By asking participants to fill out questionnaires about their physical activity during the summer and winter, both at work and at leisure, and taking blood samples, the researchers found nonwork-related physical activity was associated with a lower risk for heart disease.

Also significant was that those who reported more leisure time activity had lower levels of various biomarkers in the blood that are involved in the inflammatory response, which is thought to be involved in the buildup of plaque in the blood vessels.

"This study was well done for the completeness of the inflammatory markers. The authors looked very carefully at more markers," says Dr. Richard Stein, a spokesman for the American Heart Association and chief of cardiology at Brooklyn Hospital Center.

Stein says this is important because these inflammatory markers -- such as C-reactive protein (CRP) and interleukin 6 (IL-6) -- could be increasingly important in determining the causes for heart attacks.

"Coronary events are not due to how much coronary disease you have, but to the fracturing of the plaque that blocks the heart vessel," he says, and while you can't say now that having high levels of inflammatory markers can predict coronary events, research is suggesting the likelihood of these events are associated with these markers.

In the study, there was a clear relationship between leisure time physical activity and a decrease in risk of heart disease, with the benefits accruing dramatically as the amount of exercise increased. Those who exercised for an hour or less a week reduced their heart disease risk by 15 percent compared to those who did no leisure time exercise.

People who exercised between one and two hours a week had a 40 percent reduction in heart disease risk, and those who exercised for more than two hours weekly reduced their risk for heart disease by 61 percent.

"The single, most proactive thing you can do for yourself to reduce the risk for heart disease is to exercise regularly three or more times a week," Stein says.

Conversely, study participants who reported work-related physical strain (WRPS) had a much higher risk of heart disease, from a doubling of the risk for those who reported light WRPS to more that four times the risk for those who had heavy WRPS.

One reason for this difference, the authors suggest, could be that work-related physical activity is probably long-lasting and static, while leisure time activity is mainly short-lasting and dynamic in nature. But, they add, it also may be due to other, unknown risks.

Stein says that previous studies report the same discrepancy between different types of exercise but that the cause for the differences is unknown.

"It may be a mind-body connection, but it's not clear," he says.

More information

Get suggestions for increasing your physical activity from the American Heart Association. An article explaining the biomarker C-reactive protein (CRP) can be found at the National Library of Medicine.

SOURCES: Richard Stein, M.D., spokesman, American Heart Association, professor, clinical medicine, Weill Cornell Medical Center, and chief, cardiology, Brooklyn Hospital Center, New York City; May 26, 2003, Archives of Internal Medicine
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