Effect of exercise differs by gender

Poor fitness levels increase the chance of a heart attack for both sexes, but women can lower their risk more dramatically than men simply by becoming physically active.

A new study published last month in Circulation: Journal of the American Heart Assn. is the first to highlight the risk of inactivity for women.

“This is one of the most important public health issues,” said Dr. Martha Gulati, an assistant professor of medicine at Rush-Presbyterian-St. Luke’s Medical Center in Chicago, where the study was conducted. “We’ve got to start attacking it.”

Women have long been underrepresented in cardiovascular research, and this study helps close some of that gender gap, researchers say.

In 1992, researchers began tracking more than 5,700 women with a median age of 52 who had no symptoms of heart disease. The women were asked about medical and family history and were given an exercise stress test on a treadmill. A fitness level, ranging from a least-fit score of 1.5 to the most-fit score of 20, was assigned to each woman based on her performance.

At the end of the study, researchers found that for every 1-point increase in fitness level, there was a 17% decrease in the overall risk of death over the next eight years. A similar study of men showed only about an 8% decrease in deaths for roughly the same amount of fitness-level improvement. Gulati said her study provides a “clear, clinical rationale” for the routine stress testing of middle-aged women who have no symptoms of heart disease.

“Knowing a person’s physical fitness provides information beyond blood pressure, cholesterol levels and whether someone smokes,” Gulati said. “It’s remarkably easy and important to assess it. And we should.”

However, in an editorial accompanying the study, two doctors from the Duke Clinical Research Institute in Durham, N.C., said more data is needed before they could recommend exercise stress testing for female patients without heart disease symptoms.