title: Impaired interval exercise responses in elite female cyclists at moderate simulated altitude.
abstract: The effect of hypoxia on the response to interval exercise was determined in eight elite female cyclists during two interval sessions: a sustained 3 x 10-min endurance set (5-min recovery) and a repeat sprint session comprising three sets of 6 x 15-s sprints (work-to-relief ratios were 1:3, 1:2, and 1:1 for the 1st, 2nd, and 3rd sets, respectively, with 3 min between each set). During exercise, cyclists selected their maximum power output and breathed either atmospheric air (normoxia, 20.93% O(2)) or a hypoxic gas mix (hypoxia, 17.42% O(2)). Power output was lower in hypoxia vs. normoxia throughout the endurance set (244+/-18 vs. 226+/-17, 234+/-18 vs. 221+/-25, and 235+/-18 vs. 221+/-25 W for 1st, 2nd, and 3rd sets, respectively; P< 0.05) but was lower only in the latter stages of the second and third sets of the sprints (452+/-56 vs. 429+/-49 and 403+/-54 vs. 373+/- 43 W, respectively; P<0.05). Hypoxia lowered blood O(2) saturation during the endurance set (92.9+/-2.9 vs. 95.4+/-1.5%; P<0.05) but not during repeat sprints. We conclude that, when elite cyclists select their maximum exercise intensity, both sustained (10 min) and short-term (15 s) power are impaired during hypoxia, which simulated moderate ( approximately 2,100 m) altitude.
authors.affiliation: Exercise Metabolism Group, Department of Human Biology and Movement Science, Royal Melbourne Institute of Technology University, Bundoora, Victoria 3183, Australia 2616.
authors.forename: M J
authors.initials: MJ
authors.lastname: Brosnan
authors.forename: D T
authors.initials: DT
authors.lastname: Martin
authors.forename: A G
authors.initials: AG
authors.lastname: Hahn
authors.forename: C J
authors.initials: CJ
authors.lastname: Gore
authors.forename: J A
authors.initials: JA
authors.lastname: Hawley
mesh_terms: D000143:Acids / Q000097:blood; D000531:Altitude; D001639:Bicarbonates / Q000097:blood; D001642:Bicycling; D004311:Double-Blind Method; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D000860:Hypoxia / Q000503:physiopathology*; D019344:Lactic Acid / Q000097:blood; D010092:Oximetry; D010100:Oxygen / Q000008:administration & dosage* / Q000097:blood; D010108:Oxyhemoglobins / Q000378:metabolism; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology*; D012420:Running / Q000502:physiology
chemical_list: D000143:Acids; D001639:Bicarbonates; D010108:Oxyhemoglobins; D019344:Lactic Acid; D010100:Oxygen