['To investigate the effect of physical training on leptin levels in elderly, obese patients with type 2 diabetes mellitus.', 'Twenty men and 38 women with type 2 diabetes mellitus with a body mass index (BMI) of > 25 kg/m2 participated in a prospective randomized study. Patients were either on oral glucose lowering drugs (n = 39) or insulin therapy (n = 19). Physical training consisted of a guided, standardized, 6-week training programme performed in the hospital on a cyclo ergometer followed by a 6-week period of guided training at home and ended in a 12-week period of training at home without supervision. Clinical data and laboratory samples including fasting insulin and leptin levels and maximal aerobic capacity were assessed at the start of the study and at 6 and 26 weeks thereafter.', 'Physical training resulted in significantly positive changes in maximal aerobic capacity (VO2max) and maximum work load. No effects of physical training on serum leptin levels and insulin concentrations were detected. Leptin levels were strongly correlated with body mass index (r = 0.63), body fat content (r = 0.61), and fasting insulin concentrations (r = 0.38). Women had threefold higher leptin levels than men. No differences in leptin levels between patients on insulin therapy and patients on oral glucose lowering drugs were found.'] Are serum leptin levels influenced by physical training in type 2 diabetes mellitus patients?