A large-scale review of studies testing the effects of exercise in people with intermittent claudication, the most common symptom of peripheral arterial disease, suggests that regular walking - although moderately painful -- is beneficial, according to an article in the December 12th issue of The New England Journal of Medicine. Investigators evaluated more than 120 studies to reach their conclusions.

Peripheral arterial disease affects eight to ten million American adults, including five percent of people ages 50 years and older. The classic symptoms of leg pain, ache, and fatigue are due to the inability of peripheral arteries to deliver enough blood to meet the increased oxygen demands of walking or other exercise.

"Unlike coronary artery disease patients, who should stop exercising as soon as they experience chest pain, peripheral arterial disease patients with cramping pain, called claudication, should walk until they reach a moderate level of leg pain and then continue for several minutes," says Kerry J. Stewart, Ed.D., lead author of the study. "After a few minutes of rest, the walking should be resumed, and this cycle should be repeated until the person can walk for 50 minutes. A supervised exercise program in which patients walk on a treadmill several times a week may be the best way to eventually ease the pain."

Because patients with claudication experience pain when they exercise, they often stop exercising, Stewart noted. "As a result, many are so unfit they become housebound or dependent on others. In a gym setting such as a cardiac rehabilitation program, with staff monitoring and encouraging them, they're more likely to keep it up. The rewards are obvious: Studies show that patients who exercise three or more times a week for at least three months have substantial increases in the distance they can walk without painful symptoms."

Although exercise training does not appear to increase significantly the amount of blood that reaches the limbs, it increases muscle metabolism and endothelial function, which regulate blood vessels' ability to expand and contract. There also appears to be an exercise-related reduction in systemic inflammation. Another benefit is a more efficient walking style in patients who often alter the mechanics of walking to avoid pain.

Exercise also improves overall cardiovascular health -- lowering blood pressure, improving cholesterol levels, lowering blood glucose levels in diabetic patients, and reducing obesity. Stewart cautioned that patients with peripheral arterial disease should see their doctors for medical clearance before starting a walking program.

Exercise training is the cornerstone of treatment for most patients with peripheral arterial disease, along with smoking cessation and therapies (as needed) to lower blood pressure and cholesterol, control diabetes, and prevent blood clots. For patients with worsening disease, or for those who cannot or will not exercise, surgical treatments such as peripheral arterial bypass or angioplasty may be helpful.