Newswise — To keep your arteries healthy, a regular exercise program is essential, reports the June issue of the Harvard Men's Health Watch.

Arterial diseases are responsible for heart attacks and strokes, the first and third leading causes of death in American men. The culprit is atherosclerosis, in which cholesterol-laden plaques build up in the arteries. As the plaques enlarge, the arteries narrow, impairing blood flow. If a plaque ruptures, a blood clot forms that can block the artery completely, killing the cells that depend on that artery's blood supply. If this happens in an artery leading to the heart or brain, the result is a heart attack or stroke.

Exercise helps prevent atherosclerosis in a number of ways. It keeps arteries healthy by lowering bad cholesterol and boosting good cholesterol. And it reduces other risk factors for atherosclerosis and blood clots, such as high blood pressure, diabetes, obesity, and stress.

Regular exercise also helps arteries by boosting the production of nitric oxide by the cells lining the arteries, which helps circulation. And new research in mice suggests that exercise stimulates the bone marrow to produce new cells for the arterial lining, which replace aging cells and repair damaged arteries.

Even in healthy people who are free of atherosclerosis, age takes its toll on arteries. As you age, arteries become stiffer, stickier, and narrower. But scientists in Italy found that in people who exercised regularly, age had a much smaller effect on arteries.

"You don't have to be a triathlete to help your arteries stay young. Just two to three miles of brisk walking nearly every day will help," says Dr. Harvey Simon, editor in chief of the Harvard Men's Health Watch.

Also in this issue:"¢ Vitamin C"¢ Metabolic syndrome"¢ A doctor discusses: carrots and prostate cancer

Harvard Men's Health Watch is available from Harvard Health Publications, the publishing division of Harvard Medical School, for $24 per year. Subscribe at http://www.health.harvard.edu/men or by calling 1-877-649-9457 (toll free).