title: Exercise-induced oxidative stress and hypoxic exercise recovery.
abstract: Hypoxia due to altitude diminishes performance and alters exercise oxidative stress responses. While oxidative stress and exercise are well studied, the independent impact of hypoxia on exercise recovery remains unknown. Accordingly, we investigated hypoxic recovery effects on post-exercise oxidative stress. Physically active males (n = 12) performed normoxic cycle ergometer exercise consisting of ten high:low intensity intervals, 20 min at moderate intensity, and 6 h recovery at 975 m (normoxic) or simulated 5,000 m (hypoxic chamber) in a randomized counter-balanced cross-over design. Oxygen saturation was monitored via finger pulse oximetry. Blood plasma obtained pre- (Pre), post- (Post), 2 h post- (2Hr), 4 h post- (4Hr), and 6 h (6Hr) post-exercise was assayed for Ferric Reducing Ability of Plasma (FRAP), Trolox Equivalent Antioxidant Capacity (TEAC), Lipid Hydroperoxides (LOOH), and Protein Carbonyls (PC). Biopsies from the vastus lateralis obtained Pre and 6Hr were analyzed by real-time PCR quantify expression of Heme oxygenase 1 (HMOX1), Superoxide Dismutase 2 (SOD2), and Nuclear factor (euthyroid-derived2)-like factor (NFE2L2). PCs were not altered between trials, but a time effect (13 % Post-2Hr increase, p = 0.044) indicated exercise-induced blood oxidative stress. Plasma LOOH revealed only a time effect (p = 0.041), including a 120 % Post-4Hr increase. TEAC values were elevated in normoxic recovery versus hypoxic recovery. FRAP values were higher 6Hr (p = 0.045) in normoxic versus hypoxic recovery. Exercise elevated gene expression of NFE2L2 (20 % increase, p = 0.001) and SOD2 (42 % increase, p = 0.003), but hypoxic recovery abolished this response. Data indicate that recovery in a hypoxic environment, independent of exercise, may alter exercise adaptations to oxidative stress and metabolism.
authors.affiliation: School of Kinesiology, Auburn University, Auburn, AL, 36830, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Ballmann
authors.forename: Graham
authors.initials: G
authors.lastname: McGinnis
authors.forename: Bridget
authors.initials: B
authors.lastname: Peters
authors.forename: Dustin
authors.initials: D
authors.lastname: Slivka
authors.forename: John
authors.initials: J
authors.lastname: Cuddy
authors.forename: Walter
authors.initials: W
authors.lastname: Hailes
authors.forename: Charles
authors.initials: C
authors.lastname: Dumke
authors.forename: Brent
authors.initials: B
authors.lastname: Ruby
authors.forename: John
authors.initials: J
authors.lastname: Quindry
mesh_terms: D000293:Adolescent; D000328:Adult; D000531:Altitude; D001774:Blood Chemical Analysis; D018592:Cross-Over Studies; D015444:Exercise; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000097:blood / Q000378:metabolism; D008054:Lipid Peroxides / Q000097:blood; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology*; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D000099156:Superoxide Dismutase 2
chemical_list: D051547:Heme Oxygenase-1; D008054:Lipid Peroxides; D051267:NF-E2-Related Factor 2; D013482:Superoxide Dismutase; D000099156:Superoxide Dismutase 2; C495635:NFE2L2 protein, human; C496541:HMOX1 protein, human