The Effects of High-Intensity Interval Training on Oxidative Biomarkers, and Cardiac Function in Sedentary Adults with Metabolic Syndrome

Background: The present study aimed to investigate the impact of an eight-week HIIT intervention on oxidative stress markers and cardiac functional parameters in sedentary adults diagnosed with metabolic syndrome.Methods: In this randomized controlled trial, ۶۰ sedentary adults (aged ۴۰–۶۵ years) meeting the International Diabetes Federation criteria for metabolic syndrome were allocated into a HIIT group (n = ۳۰) or a control group (n = ۳۰). The HIIT group completed three supervised training sessions per week, consisting of repeated high-intensity intervals at ۸۵–۹۵% HRmax interspersed with low-intensity recovery bouts. Oxidative biomarkers—including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX)—were assessed at baseline and post-intervention. Cardiac function was evaluated using echocardiography (LVEF, LVEDD, LVESD) and heart rate variability (HRV). Statistical significance was set at p < ۰.۰۵.Results: Following the intervention, the HIIT group demonstrated significant reductions in MDA levels (p < ۰.۰۰۱) and marked increases in SOD (p = ۰.۰۰۳), CAT (p = ۰.۰۰۸), and GPX activity (p = ۰.۰۰۱), whereas no significant changes were observed in the control group. Cardiac function improved significantly in the HIIT group, with increases in left ventricular ejection fraction (p = ۰.۰۱۲), improved HRV indices (RMSSD and HF power, p < ۰.۰۵), and reductions in LVEDD (p = ۰.۰۲۸). Conclusion: This study demonstrates that an eight-week HIIT program effectively enhances antioxidant defense capacity, reduces oxidative damage, and improves cardiac functional indices in sedentary adults with metabolic syndrome.