Effects of a single session of concurrent exercise on leptin levels and insulin resistance index in sedentary males

Physical activity is known to influence and regulate leptin hormone secretion, which assists in the regulation of body weight and energy homeostasis. The purpose of the present study was to investigate the effects of a single session of concurrent exercise on leptin levels and insulin resistance, until 24 h post-exercise. Ten male subjects (22.9±1.7 years) healthy volunteer performed a single session of concurrent aerobic and resistance exercise [Aerobic exercise: 60%-70% of their maximal oxygen up take for 20 min and resistance exercise: 2 sets of 10 repetitions at 70% of 1 repetition maximum]. Leptin, glucose, insulin and insulin resistance index were measured before and 24 h after exercise. Significant difference was observed between serum leptin levels (5.75±1.06 ng.ml-1 vs, 5.06±0.62), insulin resistance index (1.21±0.18, vs. 1.03±0.13) and insulin concentration (6.02±0.54 UΙμ.ml-1 vs, 5.30±0.44). However, serum glucose levels (4.52±0.27 mmol.l-1 vs., 4.37±0.36) remained unchanged before and 24 h post-exercise. Significant correlations was observed between insulin resistance index to insulin levels (r=0.97, P=0.000) and glucose (r=0.91, P=0.000) and also between serum leptin to insulin levels (r=0.73, P=0.02) and insulin resistance index (r=0.68, P=0.038) (P<0/05). Results of this study indicated that even a single session of concurrent aerobic and resistance exercise with significant change in leptin levels could have positive effects on insulin resistance index.