What Are the Specific Benefits of Exercise?

Effects on Bones and Joints

Osteoarthritis. Exercise helps to reduce pain and stiffness, and increases flexibility, muscle strength, endurance, and well being. Exercising also helps people reduce their weight and maintain weight loss. Osteoarthritis patients should avoid high-impact sports such as jogging, tennis, and racquetball. The three types of exercise that are best for people with arthritis are range of motion, strengthening (or resistance), and aerobic exercises. Strengthening exercises include isometric exercises (pushing or pulling against static resistance) and stretching exercises to build strength and flexibility without unduly stressing the joints. These exercises may be particularly important if leg muscle weakness turns out to be a cause of osteoarthritis, as some research suggests. Low-impact aerobics also help stabilize and support the joints and may even reduce inflammation in some joints. Cycling and walking are beneficial, and swimming or exercising in water is highly recommended for people with arthritis.
One study compared a group of patients who embarked on an aerobic and resistance exercise program with a group that received patient education; the exercising group developed less disability and pain and showed a better ability to perform physical tasks. Patients should strive for short but frequent exercise sessions guided by physical therapists or certified instructors.

Osteoporosis. Exercise is very important for slowing the progression of osteoporosis. Women should begin exercising before adolescence, since bone mass increases during puberty and reaches its peak between ages 20 and 30. Weight bearing exercise, which applies tension to muscle and bone, encourages the body to compensate for the added stress by increasing bone density by as much as 2% to 8% a year. High-impact weight-bearing exercises, such as step aerobics, are very protective for premenopausal women. These exercises, however, increase the risk for osteoporotic fractures in elderly patients, who would benefit most from regular, brisk, long walks. Even moderate exercise (as little as an hour a week) helps reduce the risk for fracture, but everyone who is in good health should aim for more. Careful weight training is beneficial as well for older women. Low-impact exercises that improve balance and strength, particularly yoga and T'ai Chi, have been found to decrease the risk of falling; in one study, T'ai Chi reduced the risk by almost half.

Back Problems. One of the most common complaints of modern men and women, lower-back pain, afflicts up to 80% of all Americans. Sedentary living, obesity, poor posture, badly designed furniture, and stress all contribute to back pain. An appropriate exercise program focusing on flexibility and strengthening the muscles in the abdomen may help prevent back problems. Yoga stretching is beneficial and can be incorporated into the warm-up and cool-down periods. The best exercises for athletes with bad backs include swimming, walking, and cross-country skiing. High-impact sports, including aerobic dance and downhill skiing, should be avoided. Exercises that strengthen the abdominal muscles such as partial sit-ups, which maintain the back's normal curve and help support the body's weight, can alleviate stress on the lower back. However, the classic full sit-up (raising your head and shoulders off the floor up to your knees) may aggravate back pain and should be avoided by anyone at risk for lower back problems.