How Much Exercise Do You Need to Prevent Heart Disease?

The old thought was that vigorous exercise could be dangerous to people at risk for heart disease. Emerging evidence suggests that the more vigorous the workout, the more value to your heart—though short, 15-minute spurts of exercise may be as beneficial as one marathon session.

One cardiovascular death per year may be preventable for every 145 people with diabetes who are persuaded to walk at least two hours a week, according to researchers at the Centers for Disease Control and Prevention in Atlanta.

Exercise keeps you ticking
David Cullen's brother Steve died of a heart attack in 1995 at age 40. In 2002 two more of his brothers died of the same fate, one day apart.

Cullen, a state representative from Milwaukee, doesn't expect to die young. At 5'11", he weighs only 165 pounds and has low cholesterol. He credits his good health to running six to eight miles each day.

How exercise clears arteries
Exercise helps dilate the body's blood vessels and enables blood to circulate more freely, said Byung-il William Choi, MD, a professor of cardiovascular medicine at the Medical College of Wisconsin in Milwaukee.

In one study Harvard researchers found up to a 20% reduction of heart-disease risk for those who most frequently got vigorous exercise. This category included running or jogging, swimming laps, playing tennis, or doing aerobics.

Walking three miles or more a week resulted in a 10% reduction in risk. Other moderate exercises include walking, golf, and yard work.

"The benefits of physical activity seem to be independent of other coronary factors," Howard D. Sesso, ScD, of the department of epidemiology at the Harvard School of Public Health, said when the study was published.