• Whether you're 9 or 90, abundant evidence shows exercise can enhance your health and well-being. While many of us know this, far too few act upon it. Years ago, practically every American could count on getting a good dose of physical activity from everyday tasks and recreation. Today, cars, industrial machinery, and labor-saving appliances eliminate much of the physical work of daily life. Sedentary pastimes, such as watching TV, surfing the Internet, or playing computer and video games, have replaced more active pursuits. Millions of Americans simply aren't moving enough to meet the minimum threshold for good health — that is, burning at least 700–1,000 calories a week through physical pursuits. For most people, this translates into getting at least 30 minutes of moderate activity a day — the current government recommendation. Yet fewer than half of American adults meet this goal. Worse, more than one in three is completely sedentary.

• Just how much difference does staying active make? Literally hundreds of studies conducted over more than half a century demonstrate that regular exercise pares down your risk for developing some of the most lethal health problems, including heart disease, diabetes, stroke, and some forms of cancer. It eases the toll of chronic ailments like high blood pressure, diabetes, and arthritis. Put simply, exercise helps you feel better and live longer.

• Perhaps you're not sure how much exercise you must do to reap these gains or which activities will prove most helpful. Must you take up jogging? Spend hours huffing and puffing on treadmills at a gym? Neither is necessary. Just half an hour of moderately intense activity on all or most days of the week delivers solid health benefits. And you needn't perform this activity all at once; you can break it up into three 10-minute segments if you wish. A blend of activities is important, too. Cardiovascular workouts, muscle-strengthening exercises, and stretching and balance sessions all work together to help ward off or ease disability and illness. Ultimately, this helps you stay independent and enjoy a high quality of life in your later years.