Investigation of Lipid Peroxidation and Salivary Antioxidant Markers in Exercise Training: A Meta-analysis Study

Introduction and purpose: Many studies have pointed out the benefits of exercise training in preventing various diseases. In the body's physiological conditions, there is a balance between oxidants and antioxidants, which plays an important role in health. However, performing exercise training by increasing the metabolism and oxygen consumption rate causes this balance to be disturbed. In this meta-analysis, malondialdehyde as an oxidative index and the activity of catalase and superoxide dismutase enzymes as salivary antioxidant indices were investigated concerning exercise training in non-athletes. Methods: All articles published in Persian and English until September 2024 were searched from PubMed, Google Scholar, ScienceDirect, Scientific Information Database (SID), Scopus, and Irandoc databases and included in the meta-analysis. Fixed and random effects models for meta-analysis of average effect size (difference in mean with 95% confidence interval) in research related to malondialdehyde (11 studies), catalase (9 studies), and superoxide dismutase (9 studies) were performed with the help of CMA2 software. Results: The present meta-analysis indicated that exercise training caused a significant increase in malondialdehyde (ES=1.253, 95%CI=1.05 to 1.45, P=0.001), catalase (ES=2.235, 95%CI= 0.75 to 3.719, P=0.001), and superoxide dismutase (ES=0.894, 95%CI= 0.660 to 1.128, P=0.001). Conclusion: The results demonstrated that exercise training increases the production of malondialdehyde, which is an indicator of oxidative stress, and on the other hand, the antioxidant defense system increases as a biological reaction of the body to neutralize the destructive effects of free radicals.