Scientific Publications Database

Article Title: Oxidative stress does not influence local sweat rate during high-intensity exercise
Authors: Meade, Robert D.; Fujii, Naoto; Poirier, Martin P.; Boulay, Pierre; Sigal, Ronald J.; Kenny, Glen P.
Journal: EXPERIMENTAL PHYSIOLOGY Volume 103 Issue 2
Date of Publication:2018
Abstract:
New Findings What is the central question of this study? We evaluated whether oxidative stress attenuates the contribution of nitric oxide to sweating during high-intensity exercise.What is the main finding and its importance? In contrast to our previous report of an oxidative stress-mediated reduction in nitric oxide-dependent cutaneous vasodilatation in this cohort during intense exercise, we demonstrated no influence of local ascorbate administration on the sweating response during moderate- (approximate to 51% peak oxygen uptake) or high-intensity exercise (approximate to 72% peak oxygen uptake). These new findings provide important mechanistic insight into how exercise-induced oxidative stress impacts sudomotor activity.Nitric oxide (NO)-dependent sweating is diminished during high- but not moderate-intensity exercise. We evaluated whether this impairment stems from increased oxidative stress during high-intensity exercise. On two separate days, 11 young (24 +/- 4years) men cycled in the heat (35 degrees C) at a moderate [500W; 52 +/- 6% peak oxygen uptake (V-O2 peak )] or high (700W; 71 +/- 5% V-O2 peak ) rate of metabolic heat production. Each session included two 30min exercise bouts separated by a 20min recovery period. Local sweat rate was monitored at four forearm skin sites continuously perfused via intradermal microdialysis with the following: (i) lactated Ringer solution (Control); (ii) 10mm ascorbate (Ascorbate; non-selective antioxidant); (iii) 10mmN(G)-nitro-l-arginine methyl ester (l-NAME; NO synthase inhibitor); or (iv) 10mm ascorbate plus 10mm l-NAME (Ascorbate + l-NAME). During moderate exercise, sweat rate was attenuated at the l-NAME and Ascorbate + l-NAME sites (both approximate to 1.0mgmin(-1)cm(-2); all P<0.05) but not at the Ascorbate site (approximate to 1.1mgmin(-1)cm(-2); both P0.28) in comparison to the Control site (approximate to 1.1mgmin(-1)cm(-2)). However, no differences were observed between treatment sites (approximate to 1.4mgmin(-1)cm(-2); P=0.75) during high-intensity exercise. We conclude that diminished NO-dependent sweating during intense exercise occurs independent of oxidative stress.