The Role of Exercise in Prevention of Osteoporosis

Abstract

Summary Osteoporosis is currently the major cause of bone fractures in post-menopausal women and older people and is associated with a high personal and medical cost. Peak bone mass is achieved in the fourth decade followed by a gradual loss of bone which is less in men than women. Superimposed on this gradual age-related loss is an accelerated period of bone loss following the menopause in women. Preventive strategies against the development of osteoporosis include maximising bone mass early in life and slowing the age-related loss. It is now well established that mechanical force through gravity or muscle pull is a major factor in maintaining or increasing bone mass and strength, the improvements being specific to the bone being loaded. Conversely, physical inactivity and weightlessness are associated with loss of bone mass. Many athletes have a greater bone mass than their age-matched sedentary controls. Correlates have been also found between indices of physical activity, fitness and muscle and bone mass in relatively sedentary men and women over a wide age range. Controlled prospective trials of exercise intervention have demonstrated that physical exercise can prevent or reverse loss of bone in pre- and post-menopausal women. Additional desirable effects of increased exercise are improvements in muscle strength, cardiovascular fitness and general well-being. The combined effect of these should be to decrease the incidence of falls and therefore protect against further fractures. Further long-term studies are now required to determine the most effective form of exercise, the optimum duration and frequency and the effect that this has on fracture incidence.