INTRODUCTION
Metabolic syndrome (MetS) is recognized as a major global public health challenge in the modern era. It is characterized by a cluster of metabolic disorders, including central obesity, dyslipidemia, hypertension, and insulin resistance (1). The global prevalence of MetS is rising, with recent reports indicating it affects approximately 25%–30% of the adult population worldwide (2). This syndrome significantly increases the risk of cardiovascular diseases and type 2 diabetes and is associated with impaired antioxidant defense systems and elevated oxidative stress (3). High-Intensity Interval Training (HIIT) has gained significant attention in research due to its notable effects on improving insulin sensitivity, reducing visceral fat, and regulating lipid profiles (4). Resveratrol (RES), a natural polyphenol found in grapes and berries, has been identified as a promising supplement in previous studies owing to its antioxidant, anti-inflammatory (5), and metabolic-modulating properties (6). The present study aimed to investigate the effects of eight weeks of HIIT combined with RES supplementation on serum levels of malondialdehyde (MDA), as a marker of lipid peroxidation, and total antioxidant capacity (TAC), as an indicator of antioxidant defense, in men with MetS.

METHODS
Men aged 20–50 years diagnosed with MetS were voluntarily recruited based on inclusion and exclusion criteria. Following informed consent, the study protocol was explained to participants. They were required to attend the laboratory for three sessions over one week for coordination, anthropometric measurements, dietary assessment, and exercise intensity determination. Blood samples (5 ml) were collected from the basilic vein 24 h before the intervention and 48 h after the final session. Participants were randomly assigned to four groups (n=15 per group) using a random number table. RES capsules (250 mg) were obtained from Raha Pharmaceuticals Company, Iran. Placebo capsules (containing corn starch), identical in appearance and dosage to the RES capsules, were prepared by Baharan Pharmaceutical Company, Iran. Supplements were administered before lunch with a glass of water. The exercise protocol was conducted indoors over eight weeks under controlled temperature and humidity. Quantitative variables were compared using One-Way ANOVA, paired t-test, and ANCOVA. Data analysis was performed using the SPSS (version 25) software, with a statistical significance set at p < 0.05.

RESULTS
The findings indicated normal distribution of all physiological and anthropometric indices at baseline, with no significant differences observed between the four groups (p > 0.05). One-way ANOVA revealed no significant differences in the mean values of the studied indices between groups at baseline (p > 0.05). However, significant differences were found in post-test mean values (p ≤ 0.05). Paired t-test analysis showed that the HIIT+RES group exhibited significant post-test reductions in cholesterol, triglycerides, LDL-C, and MDA levels, alongside significant increases in HDL-C and TAC levels compared to baseline (p ≤ 0.05). Significant post-test reductions in cholesterol, triglycerides, and LDL-C were also observed in the PLC+HIIT group, and significant reductions in LDL-C and MDA were found in the RES group compared to baseline (p ≤ 0.05). Bonferroni test results indicated that mean serum levels of cholesterol, triglycerides, LDL-C, and MDA decreased in the RES, PLC+HIIT, and RES+HIIT groups compared to the PLC group. These decreases were statistically significant for cholesterol and triglycerides in the PLC+HIIT and HIIT+RES groups, for LDL-C in all three intervention groups, and for MDA in the RES and HIIT+RES groups (p < 0.05). Furthermore, the HIIT+RES group demonstrated a significant reduction in serum cholesterol and triglycerides compared to the RES group, and a significant reduction in serum MDA compared to the PLC+HIIT group (p < 0.05). No other significant pairwise differences were observed (p ≥ 0.05). Regarding HDL-C and TAC, the Bonferroni test indicated increased mean serum levels in the RES, PLC+HIIT, and RES+HIIT groups compared to PLC; however, this increase was only statistically significant in the HIIT+RES group (p < 0.05). No other significant pairwise differences were found (p ≥ 0.05).

CONCLUSION
The findings demonstrate that the combination of HIIT and RES supplementation exerts a significant synergistic effect on improving lipid profiles and oxidative stress markers in men with MetS. The significant reduction in MDA and increase in TAC observed in the combined group indicate enhanced antioxidant defense and reduced lipid peroxidation, aligning with previous research (7,10). Evidence also suggests that HIIT modulates the endogenous antioxidant system, increasing the activity of enzymes, such as Superoxide Dismutase (SOD) and Catalase (10). This anti-inflammatory effect may contribute to improved insulin resistance and lipid profiles (11). Overall, the results suggest that combining HIIT with RES represents an effective non-pharmacological therapeutic strategy for improving metabolic profiles and reducing oxidative stress in MetS patients. These findings underscore the importance of multifaceted interventions in managing the syndrome.

Ethical Considerations
Compliance with ethical guidelines
This study was approved by the Research Ethics Committee of Urmia University of Medical Sciences (Approval ID: IR.URMIA.REC.1404.013).

Funding
There is no funding support.
Authors' Contributions
All authors contributed equally to this work.
Conflict of Interest
The authors declared no conflict of interest.
Acknowledgments
The authors express their sincere gratitude to all participants who contributed to this study.