Effect of Exercise-Induced Dehydration on Circulatory Markers of Oxidative Damage and Antioxidant Capacity
Dehydration is a common event associated with exercise. However, few studies have examined the effects of dehydration on plasma redox status in humans. Eighty-two athletes were recruited and had Baseline anthropometrics and blood samples obtained. Athletes then engaged in a dehydration protocol, training until 3% of pre-weight body mass was lost. Athletes returned to the lab and had Post-dehydration blood collected. Athletes then consumed an isotonic drink until pre-exercise body weight was reestablished. Blood was then recollected (1-h post-full rehydration (PFR)). Samples were centrifuged and the plasma snap frozen in liquid nitrogen and stored at -80°C. Lipid and protein oxidative stress was determined by measuring F2-isoprostanes and protein carbonyls (PC), respectively. Antioxidant capacity was determined by the ferric reducing ability of plasma (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays. Plasma osmolality was determined using an osmometer. Statistical analysis utilized a 1-way ANOVA with post-hoc testing. Values are reported as mean ± SD. Plasma osmolality was significantly elevated immediately post-dehydration (p≤0.001) but decreased to Baseline at PFR. Plasma TEAC increased immediately post-dehydration and at PFR (p<0.001). FRAP increased immediately post-dehydration (p<0.001) and decreased to below Baseline at PFR (p<0.05). Conversely, F2-isoprostanes declined significantly from Baseline to immediately post-dehydration and then significantly rose at PFR (p≤0.001), while PC declined at PFR (p<0.01). This study indicates that dehydration and exercise cause a significant increase in plasma osmolality and antioxidant potential immediately post-exercise. We propose dehydration significantly elevates antioxidant concentration which suppresses F2-isoprostanes and PC.
Autor / Fonte:Vincent P Georgescu, Tacito P Souza-Junior, Christian Behrens, Marcelo P Barros, more. Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme 2017 February 9