Obesity; Cytokine; Insulin Resistance; Resistance Training

Obesity is a state characterized by a low-grade inflammation that leads to insulin resistance. The aim of the present study was to assess serum interleukin-18 (IL-18), interleukin-6 (IL-6), C-reactive protein (CRP) and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) in response to circuit resistance exercise in obese and normal-weight subjects with different levels of physical activity. Thirty-two healthy male students participated in the present study. Subjects were divided into 4 groups according to their BMI and level of physical activity: active obese (n=8), active non-obese (n=8), inactive obese (n=8), and inactive non-obese (n=8). To determine serum IL-6, IL-18, CRP, glucose and insulin concentrations, fasting and post-exercise blood samples were obtained. Subjects performed a bout of circuit resistance exercise in 2 sets with 10 repetitions at 60% of 1RM. Obese subjects comparing non-obese ones showed significant increase in IL-6 and significant decrease in IL-18 concentrations in response to exercise (p<0.05). There was no significant difference between active normal and inactive normal subjects in response to exercise. Also, there were not significant differences in four groups in response to exercise. The significant decrease in IL-18 concentration in the obese group comparing normal group in response to exercise was probably due to anti-inflammatory effects of exercise. Also, recommending this kind of exercise for obese persons with low level of physical activity can improve insulin resistance.