RESUMO
This study examined the effects of interval training on serum levels of leptin, cortisol, testosterone, growth hormone [GH]and insulin resistance index [HOMA-IR] in young overweight/ obese men. Eighteen previously sedentary, overweight/ obese men [BMI=31.2 +/- 3.33 Kg/m2, mean age 20 y- 3 mo] in two, the experimental and control groups, participated in 16 weeks of moderate to high intensity interval training [8-10 x 4 minutes sets of running at 60-90% of Reserve Heart Rate and 2 minutes rest interval at 40-50% of Reserve Heart Rate], three days per week. Serum levels of leptin, cortisol, testosterone, insulin, GH and HOMA-IR, and anthropometric indices were measured before and 48 hours after the last training session. Statistical analysis was done by paired and independent t-test and Pearson correlation, P value<0.05 being considered significant. Interval training resulted in decreased in levels of leptin [P=0.007] and anthropometric indices such as body fat percent, body fat mass, waist circumference and waist - to- hip ratio [P<0.05]; testosterone and cortisol levels increased following interval training [P<0.05]. However, no significant correlation was found between primary levels and alterations in leptin levels and the anthropometric indices assessed [P>0.05]. Moderate to high intensity interval training improves lipid metabolism via regulating leptin, testosterone and cortisol levels and body composition, in young overweight/ obese men, changes that may not be in line with changes occuring in insulin and GH.