A Comparison Of Bone Mineral Density And Body Composition In Post-Menopausal Athletic, Active, And Sedentary Women

Menopause has been shown to produce numerous physiological changes including decrements in bone mineral density (BMD) and increases in body fat content. Evidence suggests that physical activity may attenuate the changes observed in these measurements. However, the amount of physical activity necessary to slow the changes remains to be elucidated. The purpose of this cross-sectional study was to investigate BMD and body composition of post-menopausal women participating in various levels of physical activity. Ninety age-matched post-menopausal women (mean age+s.d. = 60.8 + 7.7 years) participated. Subjects were recruited based upon their history and level of physical activity and divided into 3 groups: Sedentary (S), n = 30; Active (AC), n = 30; and Athlete (AT); n = 30. Bone mineral content (BMC), BMD, and body composition including android and gynoid fat was determined by dual-energy x-ray absorptiometry. MANCOVA revealed higher (p < 0.05) BMD in AT and AC compared to S in the left and right femur. Total body BMD showed the same result. However, spine BMD was greater (p < 0.05) in AC than either AT or S (Table 1). Total BMC was also higher (p < 0.05) in the active groups compared to S. Body fat percentage (BF%) in S (40.8+7.8%) was higher (p < 0.05) compared to either AC (32.1+7.5%) or AT (27.4+8.1%). AT (40.3 + 4.0 kg) and AC (39.8 + 3.9 kg) had significantly larger (p < 0.05) amounts of lean body mass (LBM) than S (38.0 + 4.2 kg). No differences between AT and AC were observed for either BF% or LBM. Android (A) and gynoid (G) fat distribution patterns showed that AT (A = 30.5 + 11.2%: G = 36.9 + 8.1%) and AC (A = 35.4 + 11.5%: G = 40.9 + 6.6%) had significantly less fat distributed in these areas than did S (A = 46.2 + 11.6%: G = 47.8 + 6.2%). DISCUSSION: Results from this study support evidence indicating that long-term physical activity has positive effects on bone and body composition in post-menopausal women. However there did not appear to be any distinct advantage for the women who had been competitive athletes and who generally trained at higher exercise intensities than the recreationally active women. Moderate levels of physical activity appear to have the same beneficial effects on bone and body composition as higher intensity physical activity in post-menopausal women. This has important implications for the prevention and control of chronic diseases such as osteoporosis, obesity, and type II diabetes that occur with increasing frequency in older populations.