Effects of Exercise Training on Bone Density in Older Men and Women

Abstract
Objectives: To determine the effects of up to 14 months of aerobic exercise on measures of bone density in older adults. Design: Randomized controlled trial with subjects assigned to either an aerobic exercise condition, non‐aerobic yoga, or a wait list non‐exercise control group for 4 months. Aerobic fitness and bone density were evaluated in all subjects at baseline (Time 1) and after 4 months (Time 2). A semi‐crossover design was utilized with all subjects completing 4 months of aerobic exercise, followed by another evaluation (Time 3). All subjects were then given the option of 6 additional months of aerobic exercise, after which they had a fourth evaluation (Time 4). Setting: An outpatient exercise rehabilitation facility at a large, major medical center. Subjects: One‐hundred‐one healthy men (n = 50) and women (n = 51) over age 60 (Mean age = 67.0), recruited from the community. Intervention: The exercise program included stretching, cycle ergometry, and walking three times per week for 60 minutes throughout the course of the study. Outcome Measures: Aerobic fitness (VO2 max) as assessed by cycle ergometry, and bone density (bone mineral content) measured by single photon absorptiometry. Results: Subjects achieved a 10%–15% increase in VO2 max after 4 months of exercise training, and 1%–6% further improvement with additional training. Aerobic fitness was associated with significant increases in bone density in men, but not women, who maintained aerobic exercise for 14 months.