Many people exercise for weight control. But regular exercise can do much more: It preserves and builds muscle and bone tissue, increases flexibility, improves the body's response to insulin, and helps control blood pressure. Physical activity may lower blood cholesterol levels and increase levels of desirable HDL. The higher your HDL, the better. More to the point, studies show that active people live longer.

Increasingly, experts are recommending a combination of aerobic activity, such as brisk walking and bicycling, and strength training, commonly known as weight lifting. You don't need to jog daily or climb mountains to reap the benefits of physical activity, however. New research suggests that even moderate movement, including gardening, dancing, strolling, and household chores, promotes good health when done regularly, for 30 minutes per day, four to five times a week.