Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity

Abstract

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 F 2 -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, F 2 -isoprostanes declined significantly from Baseline to immediately postdehydration 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 F 2 -isoprostanes and PC.

Discussion of “Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity”

“…258-265. doi:10.1111/j.1553-2712.1998.tb02624.x. Georgescu, V.P., de Souza Junior, T.P., Behrens, C., Barros, M.P., Bueno, C.A., Utter, A.C., et al 2017. Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity.…”

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We read with great interest a recent article by Georgescu et al (2017) entitled "Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity". The authors aimed to investigate effects of hydration and rehydration by using sensitive indirect measures of oxidative stress and the antioxidant capacity response.

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The Effects of Dehydration on Metabolic and Neuromuscular Functionality during Cycling

“…Many studies have reported the consequences of dehydration on physical and mental levels, highlighting humoral changes and cognitive deficits, which not only compromise normal daily activities but can negatively affect sports performance [4][5][6]. More specifically, it has been shown that the inadequate restoration of fluids during exercise compromises neuromuscular function, increases fatigue perception, reduces technical skills, affecting metabolic and autonomic nervous system parameters [7][8][9][10].…”

“…Despite the importance of maintaining a euhydrated state, studies have shown individuals are not adequately replacing fluid during exercise [21]. Although many studies have investigated the physiological responses to dehydration [4][5][6][7][8][9][10][11][12], to our knowledge, no research has evaluated the impact of dehydration on both metabolic and neuromuscular variables during performance in active males. Therefore, the purpose of our study was to investigate the effects of progressive dehydration on heart rate (HR), oxygen uptake (VO 2 ), energetic cost, and neuromuscular functionality during both submaximal cycling exercise at a constant work rate and subsequent time-to-trial (TT) performance.…”

Heat and dehydration induced oxidative damage and antioxidant defenses following incubator heat stress and a simulated heat wave in wild caught four-striped field mice Rhabdomys dilectus

“…Heat stress and dehydration independently can disrupt this balance [40][41][42]. Heat stress can disrupt this balance through excessive metabolic ROS production and lowered antioxidant activity, resulting in a state of oxidative stress [43,44].…”