Effects of Two Different Training Programs on Cardiometabolic Health, Body Composition and Irisin in Middle Age Obese Males: A Pilot Study

Obesity is a chronic disease characterized by excessive fat accumulation. Irisin, released during exercise, regulates energy metabolism and may contribute to exercise-induced metabolic adaptations. This study aimed to compare the effects of 24 weeks of two different training programs on body composition, physical capacities, and irisin levels in male adults with obesity, and to investigate the relationship between irisin and metabolic parameters. Thirteen male adults with obesity were randomly assigned to polarized (POL) or threshold (THR) training programs. Anthropometric measurements, physical capacity parameters, serum and salivary samples were collected before (T0) and after the training period (T1). Irisin levels were measured by ELISA. After training, body composition significantly improved, with reductions in body mass and body mass index, and an increase in fat-free mass. Maximal oxygen consumption (V’O2max) significantly increased, while a decrease in HRmax indicated improved cardiac efficiency. Although serum and salivary irisin levels did not significantly increase overall, a trend toward increased irisin was observed in the THR group. Furthermore, serum irisin at T1 positively correlated with V’O2 at the respiratory compensation point (p = 0.019), and V’O2max (p = 0.031). Both POL and THR training programs significantly improved body composition and cardiometabolic fitness after 24 weeks. The positive association of irisin with aerobic fitness parameters suggests that irisin may reflect physiological adaptations to exercise.