Exercise effect on weight and body fat in men and women.

OBJECTIVES: The effect of national exercise recommendations on adiposity is unknown and may differ by sex. We examined long-term effects of aerobic exercise on adiposity in women and men.

RESEARCH METHODS AND PROCEDURES: This was a 12-month randomized, controlled clinical trial testing exercise effect on weight and body composition in men (N = 102) and women (N = 100). Sedentary/unfit persons, 40 to 75 years old, were recruited through physician practices and media. The intervention was facility- and home-based moderate-to-vigorous intensity aerobic activity, 60 min/d, 6 days/wk vs. controls (no intervention).

RESULTS: Exercisers exercised a mean 370 min/wk (men) and 295 min/wk (women), and seven dropped the intervention. Exercisers lost weight (women, -1.4 vs. +0.7 kg in controls, p = 0.008; men, -1.8 vs. -0.1 kg in controls, p = 0.03), BMI (women, -0.6 vs. +0.3 kg/m(2) in controls, p = 0.006; men, -0.5 kg/m(2) vs. no change in controls, p = 0.03), waist circumference (women, -1.4 vs. +2.2 cm in controls, p < 0.001; men, -3.3 vs. -0.4 cm in controls, p = 0.003), and total fat mass (women, -1.9 vs. +0.2 kg in controls, p = 0.001; men, -3.0 vs. +0.2 kg in controls, p < 0.001). Exercisers with greater increases in pedometer-measured steps per day had greater decreases in weight, BMI, body fat, and intra-abdominal fat (all p trend < 0.05 in both men and women). Similar trends were observed for increased minutes per day of exercise and for increases in maximal oxygen consumption.

DISCUSSION: These data support the U.S. Department of Agriculture and Institute of Medicine guidelines of 60 min/d of moderate-to-vigorous physical activity.