• fat distribution;
  • stable isotopes;
  • acetate correction factor;
  • upper body;
  • lower body


Objective: Previous studies have shown that fat metabolism is different in upper body (UB) and lower body (LB) obese women. The present study investigated whether the effect of low-intensity exercise training on fat metabolism is different in UB and LB obese premenopausal women.

Research Methods and Procedures: Twenty-one healthy, premenopausal women with either LB obesity (waist-to-hip ratio of ≤0.79; n = 8) or UB obesity (waist-to-hip ratio of ≥0.85; n = 13) participated in the present study. The UB obese women were matched and randomly divided in an exercise training group (UB) and a nonexercising control group (UB-C). Subjects in the UB and LB groups participated in a low-intensity exercise training program (40% Vo2max) three times per week for 12 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 increased 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 exercise training, and nonplasma fatty acid oxidation tended to increase in the UB group compared with the UB-C group (p = 0.08).

Discussion: Low-intensity exercise training increased the contribution of fat oxidation to total energy expenditure during exercise but not at rest in UB obese women. Exercise training had no significant effect on fat metabolism in the LB obese women.