Why Exercise?

Exercise may be the closest thing to the fountain of youth available. It improves overall health and appearance. It can maintain some of the body's functions that decline with aging. It can even restore some functions that have already declined. In addition, people who exercise—regardless of how much they weigh, whether they smoke, or whether they have a disorder—tend to live longer than those who do not exercise.

Specifically, exercise can do the following:

• Make the heart stronger. Then the heart can pump more oxygen-rich blood to the body with each heartbeat.
• Improve circulation. For example, muscles in the legs squeeze leg veins and help them return blood to the heart. Strengthening these muscles helps them do it more effectively.
• Decrease blood pressure.
• Decrease the levels of total and low density lipoprotein (LDL) cholesterol—the "bad" cholesterol—and increase the level of high density (HDL) cholesterol—the "good" cholesterol.
• Make muscles stronger and increase flexibility. As a result, people may be able to do more activities or do them more easily.
• Make bones denser and stronger if the exercise involves weight bearing. Weight bearing means that the body is supporting its entire weight. Examples are walking, stair climbing, and dancing. Swimming is not a weight-bearing exercise.
• Improve balance and coordination.
• Help prevent falls and fractures.
• Burn calories and thus help maintain a healthy weight.
• Help control the level of sugar in the blood and thus help prevent or control diabetes.
• Boost the immune system. The body is then better able to fight off infections.
• Increase the level of endorphins. Endorphins are chemicals in the brain that reduce pain and induce a sense of well-being. Thus, exercise may help improve mood and energy levels and may even lessen depression.
• Improve mental alertness and the ability to concentrate.
• Help with sleep.
• Make constipation less likely.

Exercise reduces the risk of coronary artery disease, heart attack, stroke, colon cancer, osteoporosis, and type 2 diabetes. It may reduce the risk of breast cancer. Risk factors for many of these disorders include obesity, abnormal cholesterol levels, high blood pressure, and, most obviously, physical inactivity. Exercise helps control all of them.

People benefit from exercise only as long as they continue exercising. If they stop, the benefits decrease within months.