The increasing prevalence of obesity is a major public health concern. Physical activity may promote weight and body fat loss. To examine the effects of exercise on total and intra-abdominal body fat overall and by level of exercise. Randomized controlled trial conducted from 1997 to 2001. A total of 173 sedentary, overweight (body mass index > or =24.0 and >33% body fat), postmenopausal women aged 50 to 75 years who were living in the Seattle, Wash, area. Participants were randomly assigned to an intervention consisting of exercise facility and home-based moderate-intensity exercise (n = 87) or a stretching control group (n = 86). Changes in body weight and waist and hip circumferences at 3 and 12 months; total body, intra-abdominal, and subcutaneous abdominal fat at 12 months. Twelve-month data were available for 168 women. Women in the exercise group participated in moderate-intensity sports/recreational activity for a mean (SD) of 3.5 (1.2) d/wk for 176 (91) min/wk. Walking was the most frequently reported activity. Exercisers showed statistically significant differences from controls in baseline to 12-month changes in body weight (-1.4 kg; 95% confidence interval [CI], -2.5 to -0.3 kg), total body fat (-1.0%; 95% CI, -1.6% to -0.4%), intra-abdominal fat (-8.6 g/cm2; 95% CI, -17.8 to 0.9 g/cm2), and subcutaneous abdominal fat (-28.8 g/cm2); 95% CI, -47.5 to -10.0 g/cm2). A significant dose response for greater body fat loss was observed with increasing duration of exercise. Regular exercise such as brisk walking results in reduced body weight and body fat among overweight and obese postmenopausal women.
