Changes in serum leptin concentrations in overweight Japanese men after exercise

To investigate the link between serum leptin concentrations and exercise.

Cross-sectional and longitudinal studies of an exercise intervention.

110 Japanese overweight men aged 32-59 years were recruited. At baseline, the average body mass index (BMI) was 28.5 +/- 2.5 kg/m2. From this group, we used data of 36 overweight men (BMI, 28.9 +/- 2.3) for a 1-year exercise programme.

Leptin was measured at baseline and after 1 year. Fat distribution was evaluated by visceral fat (V) and subcutaneous fat (S) areas measured with computed tomography (CT) scanning at umbilical levels. Anthropometric parameters, aerobic exercise level, muscle strength and flexibility were also investigated at baseline and after 1 year.

In the first analysis, using cross-sectional data, leptin was significantly correlated with total body fat (r = 0.760, p < 0.01), V (r = 0.383, p < 0.01) and S (r = 0.617, p < 0.01) areas. In the second analysis, using longitudinal data, leptin was significantly reduced after 1 year (pre 6.7 +/- 4.0 ng/ml vs. post 5.1 +/- 3.1 ng/ml, p < 0.01). Results showed that steps per day were increased, and aerobic exercise level, weight-bearing index (WBI) and insulin resistance were significantly improved. Although, there was a positive correlation between Delta leptin(positive changes in leptin after 1 year) and anthropometric measurements such as Delta body weight, Delta BMI and Delta body fat, leptin/body weight, leptin/BMI and leptin/body fat ratios were significantly reduced during exercise intervention.

The present study indicated exercise significantly lowers serum leptin concentrations, and thus it may improve the leptin resistance observed in overweight Japanese men.