Effects of high and low intensity endurance training on levels of leptin, cortisol, testosterone, growth hormone, and insulin resistance index in sedentary obese men

Introduction and purpose
: Exercise and physical activity ameliorate obesity and related complications via effecting on hormones that regulate energy homeostasis and metabolism.This study examined the influence of low intensity versus high intensity endurance training on serum levels of leptin, cortisol, testosterone, Growth Hormone (GH) and insulin resistance index(HOMA-IR) in sedentary obese men. 27 sedentary obese men (BMI=33.82.81 kg/m2,
mean aged 21 years) randomly assigned to two training and one control groups. The participants wereexposed to 16 weeks of low intensity (40-45% of heart rate reserve) and high intensity endurance training (80-85% of heart rate reserve), 50-60 minutes per session and 3 days per week. Serum levels of leptin, cortisol, testosterone, GH and HOMA-IR, and anthropometric indices were measured before and 48 hours after last training session. Statistical analysis was done by oneway ANOVA, paired ttest and Pearson correlation, and P value<005 being considered significant. Low intensity endurance training resulted in significant decreases in serum levels of leptin (P=0.020) and anthropometric indices such as weight, body fat percent and BMI (P<0.05), and significant increases in testosterone of serum (P=0.047). In addition to significant decline in leptin concentration, HOMA-IR and most of anthropometric indices (P<0.05), high intensityendurance training resulted in significant augmentations in levels of GH and cortisol (P<0.05). Furthermore, there were significant correlations between changes in serum levels of leptin andalterations of most of anthropometric indices and body composition in both training groups (P<0.05).Discussion and High intensity endurance training is more effective in the improvement of body composition and ameliorating metabolic hormonal profile than low intensity endurance training in obese men.