The effect of rapid weight changes on oxidative stress and muscle damage in female weight class athletes

Athletes resort to rapid weight loss and quick weight regain methods before competitions with the belief that competing in a lower category will give them an advantage. Although athletes think that these methods of rapid weight loss and gain will provide them with an advantage, this practice negatively affects their health and performance. Therefore, this study aimed to investigate the effects of rapid weight loss and rapid weight regain on oxidative stress and muscle damage in weight class athletes and to determine whether there is a significant difference between these effects. Twelve healthy female athletes aged 20-25 (22.25±1.60), who had competed at the national level in weight class sports for at least five years, voluntarily participated in the study. Athletes managed to rapid weight loss within five days using their chosen method, followed by rapid weight gain within 16 hours. The body weights, lean body mass, body fat, and water ratios of the participants were determined before rapid weight loss, after rapid weight loss, and after rapid weight regain. Additionally, during this process, blood samples were taken from the antecubital veins of the participants to determine their total oxidant level (TOS), total antioxidant level (TAS) and creatine kinase (CK) levels for oxidative stress and muscle damage. Single-factor analysis of variance (ANOVA), Pearson correlation analysis and simple linear regression analysis were used to analyze the data. The significance level of the data was set at p<0.05. This study showed significant differences in oxidative stress and muscle damage markers during the periods of rapid weight loss and rapid weight regain (p<0.05). The decrease in body weight by 6.39% after rapid weight loss, along with the increase of 19.44% in total antioxidant level and 161.36% in creatine kinase, was statistically significant (p<0.05). However, the increase of 8.53% in total oxidant levels and the decrease of 22.74% in the oxidative stress index were not statistically significant (p>0.05). On the contrary, rapid weight regain showed a statistically significant increase of 22.33% in total oxidant levels and 52.79% in the oxidative stress index (p<0.05), while the decreases of 6.97% in total antioxidant levels and 0.86% in creatine kinase levels were not statistically significant (p<0.05). Additionally, a significant positive relationship was found between total oxidant level and creatine kinase during periods of rapid weight loss (r=0,674, p<0.05) and rapid weight gain (r=0,875, p<0.05)It was also determined that the total oxidant level explained 39.9% of the changes in muscle damage during rapid weight loss and 74.3% during rapid weight regain. This study has shown that despite an increase in total oxidant levels during rapid weight loss, the elevation in total antioxidant levels prevented oxidative damage. In contrast, during the rapid weight gain phase, the antioxidant level was insufficient to counterbalance the rising oxidant levels, resulting in oxidative stress. Furthermore, rapid weight loss was found to increase muscle damage, while rapid weight gain was not sufficient for recovery from muscle damage.