Effect of exercise training on serum leptin levels in type 2 diabetic patients

To evaluate the effect of exercise training on serum leptin levels 50 seden tary subjects with type 2 diabetes were enrolled in either 6 weeks of aerob ic exercise training with diet therapy (n = 23) or diet therapy alone (n = 27). The training program consisted of walking and cycle ergometer exercise for 1 hour at least 5 times per week, with the intensity of exercise maint ained at 50% of maximum oxygen uptake. Serum leptin levels decreased signif icantly in the exercise training (TR) group (7.2 +/- 3.6 to 4.6 +/- 2.5 ng/ mL, P < .05), but not in the sedentary (SED) group (6.9 +/- 3.4 to 5.6 +/- 2.9 ng/mL). Leptin levels standardized for percentage body fat (dividing se rum leptin level by percentage body fat) after treatment were lower in the TR subjects compared with the SED subjects. Body weight and percentage body fat decreased in all patients; however, no significant changes were observ ed in either group. Fasting concentrations of plasma insulin and cortisol a nd the urinary excretion of 17-hydroxycorticosteroid (17-OHCS) did not diff er between the groups either before or after treatment. Fasting plasma gluc ose and hemoglobin A(1c) (HbA(1c)) improved significantly in both groups, a lthough no significant differences were observed between the groups either before or after treatment. Ventilatory threshold increased significantly in the exercise training subjects. This study demonstrates that exercise trai ning in type 2 diabetic subjects reduces serum leptin levels independent of changes in body fat mass, insulin, or glucocorticoids. Copyright (C) 2001 by WB. Saunders Company.