Effects of exercise on different antioxidant enzymes and related indicators: a systematic review and meta-analysis of randomized controlled trials

Numerous studies on the effects of exercise on antioxidant enzymes have generally concluded that regular exercise positively impacts antioxidant enzyme activity. However, some studies suggest that regular exercise may have no effect on antioxidant enzymes or could even negatively impact them. This suggests that other potential factors may influence antioxidant enzyme activity. Therefore, this study synthesizes existing literature on the effects of exercise interventions on antioxidant enzymes and employs subgroup analysis to identify factors that may influence exercise outcomes, offering insights for individuals aiming to enhance antioxidant capacity through exercise. A systematic review and meta-analysis were performed on exercise intervention studies measuring changes in blood antioxidant enzymes. This study was registered in PROSPERO (identifier: CRD 42023477230). (1) Exercise did not significantly increase superoxide dismutase (SOD) activity in women. (2) In individuals over 45 years of age, exercise did not significantly improve SOD activity or total antioxidant capacity (T-AOC) levels. (3) Regardless of exercise type, trends in SOD and catalase (CAT) activity were similar; however, only resistance exercise increased glutathione peroxidase (GPX) activity and reduced thiobarbituric Acid Reactive Substances (TBARS) levels. (4) High-intensity exercise significantly reduced CAT levels but did not significantly increase GPX levels. (5) Exercise interventions lasting more than 16 weeks showed no significant impact on the activity of SOD, CAT, or GPX. 6. Regular exercise at least three times per week significantly increased SOD and GPX activity and had a notable impact on T-AOC and TBARS levels. This study found that exercise significantly enhanced the activity of most antioxidant enzymes and overall antioxidant capacity. Moderate-to-low intensity exercise, performed at least three times per week for more than 16 weeks, demonstrated the greatest efficacy in enhancing antioxidant enzyme activity. Notably, we also found that women may need to exert more effort than men to achieve increases in antioxidant enzyme activity.