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Oxidative stress impairs NO‐dependent cutaneous vasodilation but not NO‐dependent sweating in young adults during high intensity exercise
Author(s) -
Meade Robert,
Fujii Naoto,
McGinn Ryan,
Paull Gabrielle,
Akbari Pegah,
Kenny Glen
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.993.13
Subject(s) - microdialysis , vasodilation , oxidative stress , medicine , thermoregulation , nitric oxide , intensity (physics) , heart rate , exercise intensity , endocrinology , chemistry , blood pressure , physics , quantum mechanics , central nervous system
Our recent work showed that nitric oxide (NO)‐dependent sweating and cutaneous vasodilation are diminished in young males during intermittent exercise at high (700 W) relative to moderate (400 W) rates of metabolic heat production. We tested the hypothesis that this impairment results from increased oxidative stress during high intensity exercise. On separate days, nine young (24 ± 2 years) healthy males performed two 30 min bouts of semi‐recumbent cycling in the heat (35°C, 20% RH) at a rate of metabolic heat production of i) 500 W or ii) 700 W. The first and second exercise bouts were followed by 20 and 40 min of recovery, respectively. Forearm local sweat rate (LSR) and cutaneous vascular conductance (CVC) were measured at 4 skin sites that were continuously perfused via intradermal microdialysis with: 1) lactated Ringer's solution (Control), 2) 10 mM ascorbate (ASC, antioxidant), 3) 10 mM L‐N G ‐Nitroarginine methyl ester (L‐NAME, non‐selective NO synthase inhibitor), or 4) 10 mM ASC + 10 mM L‐NAME. During moderate intensity exercise (i.e., 500 W), L‐NAME and ASC + L‐NAME reduced LSR and CVC compared to the Control site (all P < 0.05), while no effect of ASC was observed (all P > 0.05). Conversely, high intensity exercise performed at 700 W did not result in differences in LSR between treatment sites ( P = 0.85). However, compared to Control, CVC was elevated at the ASC (all P < 0.05) while it was reduced at the L‐NAME (all P < 0.05) and ASC + L‐NAME (all P < 0.05) sites. Altogether these results suggest that oxidative stress impairs NO‐dependent cutaneous vasodilation but not LSR during intense exercise. Support: Natural Sciences and Engineering Research Council of Canada.