Is there a role for exercise in the prevention of osteoporotic fractures?

OBJECTIVES: To examine whether there is a role for exercise in improving bone mineral density (BMD), particularly in postmenopausal women. The effects of different types of exercise are examined together with their effects at selected skeletal sites. The role of activity in reducing falls and hip fractures will also be considered as well as the potentially negative effects of excessive exercise.
METHODS: A literature search over the past 20 years was conducted and landmark papers selected.
RESULTS: Certain types of exercise have been found to exert moderate benefits on BMD of the wrist, spine, and hip. Most studies do not detect a difference between the effects of endurance activities and strength training for BMD of the spine. It has been more difficult to isolate the optimal type of activity for effecting an osteogenic response at the hip, but recent evidence suggests that high impact work such as stepping and jumping may be effective at this site. The combination of hormone replacement therapy and exercise would appear to be more effective than either intervention on its own. Certain types of exercises have additional benefits, such as muscle strengthening, which could reduce the incidence of falls. Excessive exercise can lead to menstrual disturbances in female athletes and this in turn can cause bone loss, particularly from the spine.
CONCLUSIONS: Exercise across the life span should be encouraged in order to maximise peak bone mass, reduce age related bone loss, and maintain muscle strength and balance. Although the effects of exercise on BMD later in life are small, epidemiological evidence suggests that being active can nearly halve the incidence of hip fractures in the older population. This effect is most probably multifactorial through the positive effects on bone, muscle strength, balance, and joint flexibility. Younger women should be aware of the dangers to the skeleton of menstrual disorders.