The effect of low-intensity exercise training on fat metabolism of obese women

Objective: Previous studies have shown that fat metabolism is different in upper body (UB) and lower body (LB) obese women. The present study investig ated whether the effect of low-intensity exercise training on fat metabolis m is different in UB and LB obese premenopausal women. Research Methods and Procedures: Twenty-one healthy, premenopausal women wi th either LB obesity (waist-to-hip ratio of less than or equal to0.79; n = 8) or UB obesity (waist-to-hip ratio of greater than or equal to0.85; n = 1 3) participated in the present study. The UB obese women were matched and r andomly divided in an exercise training group (UB) and a nonexercising cont rol group (UB-C). Subjects in the UB and LB groups participated in a low-in tensity exercise training program (40% Vo(2)max) three times per week for 1 2 weeks. Before and after the intervention, measurements of fat metabolism at rest and during exercise, body composition, and maximal aerobic capacity were performed. Results: Exercise training did not change the respiratory exchange ratio at rest in the UB and LB groups. During exercise, relative fat oxidation incr eased in the UB group by 19% (p < 0.05), whereas no change in the LB and UB -C groups was found. Plasma free fatty acid oxidation did not change by exe rcise training, and nonplasma fatty acid oxidation tended to increase in th e UB group compared with the UB-C group (p = 0.08). Discussion: Low-intensity exercise training increased the contribution of f at oxidation to total energy expenditure during exercise but not at rest in UB obese women. Exercise training had no significant effect on fat metabol ism in the LB obese women.