Aerobic exercise maintains regional bone mineral density during weight loss in postmenopausal women

This studyexamines the effects of weight loss by caloric restriction (WL) andaerobic exercise plus weight loss (AEx+WL) on total and regional bonemineral density (BMD) in older women. Healthy,postmenopausal women age 63 ± 1 (SE) yr] not onhormone-replacement therapy underwent 6 mo of WL(n = 15) consisting of dietarycounseling one time per week with a caloric deficit (250-350kcal/day) or AEx+WL (n = 15)consisting of treadmill exercise three times per week in addition tothe weight loss. Maximal aerobic capacity increased only in the AEx+WLgroup (P < 0.001). Body weight,percent fat, and fat mass decreased similarly in both groups(P < 0.005), with no changesin fat-free mass. Total body BMD (by dual-energy X-rayabsorptiometry) decreased in both groups(P < 0.05). Femoral neck, Ward'striangle, and greater trochanter BMD decreased in the WL group(P  0.05) but were not significantlydifferent after AEx+WL.L₂-L₄BMD did not significantly change in either group. Thus WL andAEx+WL both result in losses of totalbody BMD; however, AEx+WL appears to prevent the loss in regional BMDseen with WL alone in healthy, older women. This suggests that theaddition of exercise to weight-loss programs may reduce the risk forbone loss.