Introduction: The use of antioxidants before high-intensity training, which leads to the release of free radicals and muscle injuries, can result in reduced damage during exercise. Accordingly, in this study, we aimed to evaluate the effect of selenium supplement intake on oxidative stress, following exhaustive aerobic exercise among young physically-active females.Methods: In this quasi-experimental study, 20 healthy girls (age: 23.6±1.5 years, height: 1.61±0.0126 m, and weight: 60.2±7.13 kg) were randomly divided into exercise (n=10) and supplement+exercise (n=10) groups. The participants were asked to consume selenium supplements (200?g/day) for a period of 14 days. The Bruce protocol stress test was conducted 24 h after the final intake of supplements and primary blood collection (in a fasting state). Also, immediately after performing the Bruce test, the second blood samples were drawn from the subjects. Oxidative stress markers (i.e., creatine kinase, lactate dehydrogenase, and malondialdehyde levels) were measured at each stage of blood sampling and were compared between the groups using paired t-test. Data analysis was performed by SPSS (version 18). Pvalue less than 0.05 was considered statistically significant.Results: The results indicated that exhaustive aerobic exercise could cause a significant increase in creatine kinase, lactate dehydrogenase, and malondialdehyde levels. The comparison between the control and intervention groups suggested the significant effect of selenium supplementation on declining of lactate dehydrogenase level (P<0.05).Conclusion: The results of the present study demonstrated that selenium supplements could reduce oxidative stress, induced by exhaustive physical exercise.
