Effects of 12 Weeks of Moderate-Intensity Continuous Training and High-Intensity Interval Training on Irisin, Inflammatory Cytokines, and Hepatic Aminotransferases in Obese Adult Men

This study compared the effects of 12 weeks of energy-matched high-intensity interval training (HIIT, 85–95% HRR, VO2R) and moderate-intensity continuous training (MICT, 60–65% HRR, VO2R) on circulating irisin, inflammatory cytokines (TNF-α, IL-6), and hepatic aminotransferases (ALT, AST) in obese adult men. Thirty-seven men aged 30–49 years (body fat ≥25%; BMI ≥25 kg/m²) were randomly assigned to MICT (n=18) or HIIT (n=19) and trained on a treadmill three times/week for 12 weeks. Exercise duration was individually adjusted to achieve 300 kcal per session in both groups. VO2max, body composition, and blood irisin, TNF-α, IL-6, ALT, and AST were assessed pre/post, and two-way repeated-measures ANOVA was performed. Both groups improved; however, significant group×time interactions for VO2max, body fat percentage, and fat mass indicated greater improvements with HIIT. Irisin increased significantly only in the HIIT group, and reductions in TNF-α, IL-6, ALT, and AST were also significantly greater with HIIT than with MICT. In conclusion, under matched energy expenditure, HIIT (85–95% HRR) is more effective than MICT (60–65% HRR) for improving cardiorespiratory fitness and adiposity while increasing irisin and reducing systemic inflammation and liver enzyme levels.