Context: The increasing prevalence of obesity is a major public health concern. Physical activity may promote weight and body fat loss.
Objective: To examine the effects of exercise on total and intra-abdominal body fat overall and by level of exercise.
Design: Randomized controlled trial conducted from 1997 to 2001.
Setting and participants: 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.
Intervention: 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).
Main outcome measure: 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.
Results: 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.
Conclusions: Regular exercise such as brisk walking results in reduced body weight and body fat among overweight and obese postmenopausal women.