Abstract Background and aims:It has recently been documented that obesity is a global problem in all age groups, so that it affects about 250 million people in the world, accounting for 7% of the world’s population. Adipose tissue has an important role in inducing lung dysfunction through production and secretion of adipokines such as leptin. The aim of this study was to investigate the effect of a period of aerobic training on lung function indices and serum leptin levels in obese men. Methods:A total of 23 untrained obese men in Arak were recruited voluntarily for the study and randomly assigned to obese aerobic training group (Ob-AT, n = 12) (45.26 ± 2.45 years, body mass index (BMI) of 31.81 ± 0.77 kg/m 2 ) and obese control group (Ob-Cnt, n = 11) (47.03 ± 3.36 years, BMI of 31.45 ± 0.96 kg/m2). Another normal control group (No-Cnt, n = 9) was sampled from individuals with normal weight to compare at the base level (45.1 ± 4.1 years, BMI of 24.63 ± 0.45 kg/m 2 ). The obese exercise group participated in 12 weeks of progressive aerobic training, 3 sessions a week, 1.5 hours per session. Body composition (CT scan), leptin levels and lung function were measured before and after exercise protocol. Results: The participants with normal weight had significantly lower leptin concentration (P = 0.01) and a higher lung function (P = 0.016) compared to the obese participants. Moreover, the results indicated that leptin and obesity had an inverse correlation with lung function indices (forced vital capacity [FVC] and forced expiratory volume in one second [FEV 1 ]) (P ≤ 0.05). After the aerobic activity, obesity (BMI, WHR, body fat) and lung function indices (FVC and FEV1 ) significantly decreased in the obese aerobic training group compared to the obese control group(P ≤ 0.05). In contrast, leptin concentration significantly decreased after the aerobic exercise protocol (P = 0.018). Conclusion:We found that leptin level decreased after 12 weeks of aerobic exercise in obes
