Why Use Exercise to Keep Bones Healthy & Strong?

The elderly can reduce the risk of fractures by exercising regularly.

The health of your bones affects your quality of life and physical well being. If your bones are unhealthy, your mobility becomes limited and you have less protection against crippling fractures and other injuries. According to “Bone Health and Osteoporosis: A Report of the Surgeon General” by the U.S. Department of Health & Human Services, about 1.5 million Americans experience a fracture related to osteoporosis, a disease in which your bones become porous and fragile. While vigorous exercise has been shown to promote an increase in bone mineral content, about 25 percent of all Americans don’t exercise at all.

Amount of Exercise and Skeletal Adaptation

Your skeletal system adapts to the amount of exercise you do. Adaptation also depends on the type of bone, spongy or compact and dense, that's being measured, and the type of activity that’s being done. A sedentary lifestyle with little to no activity can result in low mineralization and bone density. It can also lead to age-related osteoporosis. Your bones can grow fragile, which increases the risk of fractures and injury, according to Sharon Plowman’s book “Exercise Physiology.” If you exercise regularly, your bones will develop at a normal rate. The mineralization of your bones will be adequate if not improved. Exercise can also retard osteoporosis at a later age. But if your exercise regimen is excessive -- of long duration and high intensity -- it can damage your bones. Female athletes who have irregular periods can suffer from osteoporosis and other bone-related conditions. Overuse injuries can include inflammation, spurs, fractures and slippage of the vertebrae.

Weight-Bearing Exercise

According to the American College of Sports Medicine’s “Complete Guide to Fitness and Health,” rigorous aerobic activity can maintain or increase the bone mass of your spine and hips at every age. Aerobic exercise also builds your nervous, muscular and cardiovascular systems. The exercise should be weight-bearing and can include jogging, fast walking, aerobic dance, bench stepping, stair climbing, rowing and tennis. For children and teenagers, activities that involve high-intensity loading forces, such as gymnastics, plyometrics and vigorous resistance training, can lead to increased bone mass. These gains are then maintained into adult years. For your bones to enjoy the benefits of aerobic activity, do at least 30 minutes of moderate-intensity exercise five days weekly.

Walking

While walking has been touted as a weight-bearing exercise that benefits your bones, research has indicated that sedentary women who start a walking program have not shown improved bone mass. Surveys have indicated a link between walking and reduced fractures, but the results are inconclusive, according to the American College of Sports Medicine. Studies have shown that walking at the pace of a racewalker can strengthen your spine. However, a racewalker’s pace at 5 to 6 miles per hour far outdoes an even brisk walking pace of 2 to 3 miles per hour. To improve bone health, the American College of Sports Medicine recommends that you intersperse uphill climbs and stretches of very quick walking into your walking program.

A Sedentary Lifestyle

If you don’t do weight-bearing exercise, you can lose bone mass -- as shown in patients who are bedridden as well as astronauts, according to Plowman. When you break a bone and it’s put in a cast, your compact bones will atrophy faster than your spongy bones. As an adult, your goal should be to maintain bone mass. While it’s not clear that exercise will increase bone density in adults as it does in children, it appears that exercise will retard the onset of age-associated fragility of the bones. People who remain active into advance age experience fewer fractures.

References

• Exercise Physiology: Basis of Human Movement in Health and Disease; Stanley P. Brown et al.
• Exercise Physiology; Sharon A. Plowman et al.
• ACSM’s Complete Guide to Fitness and Health; Barbara Ann Bushman
• U.S. Department of Health & Human Services: Bone Health and Osteoporosis: A Report of the Surgeon General
• NHS Choices: Osteoporosis

Resources

• Medicine & Science in Sports & Exercise: Physical Activity and Bone Health; Wendy Kohrt et al.