Exercise effect on weight and body fat in men and women

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.

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).

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.

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