Effects of circuit resistance training on serum myokine METRNL, cytokines, insulin resistance, body composition, and lipid profile in overweight participants: A 6-week intervention study

Abstract Objectives: This study investigated the effects of circuit resistance training (CRT) on Meteorin-like protein (METRNL), interleukin-4 (IL-4), interleukin-13 (IL-13), and metabolic health markers in overweight individuals. Methods: Thirty overweight male university students (BMI 25-30 kg/m²) were randomly assigned to a 6-week CRT intervention group (n=15) and a control group (n=15). The CRT program comprised three weekly 45-minute sessions at 60-70% of one-repetition maximum. Serum METRNL, IL-4, IL-13, insulin resistance index, body composition, and lipid profile were measured pre-and post-intervention. Results: The CRT group showed significant improvements compared to controls. Body mass index and body fat percentage decreased, while serum METRNL, IL-4, and IL-13 levels increased significantly (p<0.05). Metabolic health markers improved, with reductions in fasting blood glucose, fasting insulin, HOMA-IR, total cholesterol, triglycerides, and LDL-C, and increased HDL-C (p<0.05). Lean body mass remained unchanged between groups. Conclusions: CRT effectively enhances METRNL secretion, potentially contributing to improved immune and metabolic functions in overweight individuals. This suggests its potential as a therapeutic strategy for managing obesity-related immunometabolic disorders, warranting further investigation.