Exercise and Bone Mass

Swimming: The importance of physical activity for maintenance of skeletal health is generally recognized. Weight-bearing activity has been commonly considered to be essential for the beneficial effects of exercise on the skeleton; swimming, therefore, has been considered to be of little value in the maintenance of bone mass. Results of a new study suggest otherwise.

A group of men and women aged 40 to 85 years, competitors in the 1986 Masters Long Course National Swimming Championship held in Portland, Oregon, or regular swimmers who did not compete, participated in the study. They had all been swimming regularly (at least three hours a week for at least three years) but had engaged in no other form of exercise. They were compared with a similar group of nonexercising control subjects. Dietary calcium and protein intakes were similar in the two groups.

Male swimmers had significantly greater bone mineral density at both radial and vertebral sites compared with male controls, after the effects of age had been considered. No relationship between swimming and bone mineral density could be identified in women, however.

"These results suggest that swimming exercise may be beneficial in the prevention or therapy of osteopenia and that its usefulness in this regard should be further investigated." In view of its tremendous popularity, the ready availability of swimming facilities, and the relative safety and non-traumatic nature of swimming as an exercise, it seems particularly suitable for the elderly for the prevention and therapy of bone mineral loss.

ES Orwoll et al, The Relationship of Swimming Exercise to Bone Mass in Men and Women, Archives Internal Medicine 149(10):2197-2200 (Oct 1989) [Reprints: ES Orwoll, MD, Veterans Administration Medical Center (111), PO Box 1034, Portland OR 97207]