Determinants of body composition in postmenopausal women

Background. Little is known about the effects of different levels of long-t erm physical activity on total body and regional fat and whether hormone re placement therapy interacts with physical activity level to affect body com position in postmenopausal women. Methods. We determined the associations between different levels of habitua l physical activity, hormone replacement therapy (HRT), and total and regio nal body composition in postmenopausal women. Twenty sedentary, 20 active n onathletic, and 23 endurance-trained women (approximately half on HRT) had total and regional body composition assessed by dual-energy x-ray absorptio metry. The athletes and active nonathletic women had been active for the sa me number of years and the same number of hours per week. Results, The athletes and sedentary women weighed the same, but the active nonathletic groups on and not on HRT weighed 3-12 kg more (p < .05). Athlet es had less trunk, arm, leg, and total body fat than sedentary and active n onathletic women (p < .05). Women on HRT tended to have lower total body (p = .07), but not regional, fat values. Linear regression analyses indicated that (V) over dot O-2 max in ml/kg/min was the major independent determina nt of total and regional; body fat accounting for 52% to 70% of their varia nces. Athletes had greater caloric and carbohydrate intake than their less active peers, but all groups had similar protein, fat, saturated fat, monou nsaturated fat, and polyunsaturated fat intakes. Conclusions. Intense training, but not low- to moderate-intensity physical activity, is associated with markedly lower levels of total and regional bo dy fat in postmenopausal women. HRT has less of an effect on body compositi on than intense exercise training in postmenopausal women.