title: Responses to exercise in normobaric hypoxia: comparison of elite and recreational ski mountaineers.
abstract: OBJECTIVE
  Hypoxia is known to reduce maximal oxygen uptake (VO(2max)) more in trained than in untrained subjects in several lowland sports. Ski mountaineering is practiced mainly at altitude, so elite ski mountaineers spend significantly longer training duration at altitude than their lower-level counterparts. Since acclimatization in hypobaric hypoxia is effective, the authors hypothesized that elite ski mountaineers would exhibit a VO2max decrement in hypoxia similar to that of recreational ski mountaineers.
  
  
  METHODS
  Eleven elite (E, Swiss national team) and 12 recreational (R) ski mountaineers completed an incremental treadmill test to exhaustion in normobaric hypoxia (H, 3000 m, F(1)O(2) 14.6% ± 0.1%) and in normoxia (N, 485 m, F(1)O(2) 20.9% ± 0.0%). Pulse oxygen saturation in blood (SpO(2)), VO(2max), minute ventilation, and heart rate were recorded.
  
  
  RESULTS
  At rest, hypoxic ventilatory response was higher (P < .05) in E than in R (1.4 ± 1.9 vs 0.3 ± 0.6 L · min⁻¹ · kg⁻¹). At maximal intensity, SpO(2) was significantly lower (P < .01) in E than in R, both in N (91.1% ± 3.3% vs 94.3% ± 2.3%) and in H (76.4% ± 5.4% vs 82.3% ± 3.5%). In both groups, SpO(2) was lower (P < .01) in H. Between N and H, VO(2max) decreased to a greater extent (P < .05) in E than in R (-18% and -12%, P < .01). In E only, the VO(2max) decrement was significantly correlated with the SpO(2) decrement (r = .74, P < .01) but also with VO(2max) measured in N (r = .64, P < .05).
  
  
  CONCLUSIONS
  Despite a probable better acclimatization to altitude, VO(2max) was more reduced in E than in R ski mountaineers, confirming previous results observed in lowlander E athletes.
authors.affiliation: Dept of Physiology, Faculty of Biology and Medicine, University of Lausanne, Switzerland.
authors.forename: Raphael
authors.initials: R
authors.lastname: Faiss
authors.forename: Claudia
authors.initials: C
authors.lastname: von Orelli
authors.forename: Olivier
authors.initials: O
authors.lastname: Dériaz
authors.forename: Grégoire P
authors.initials: GP
authors.lastname: Millet
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000328:Adult; D015444:Exercise / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D009051:Mountaineering / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology; D012119:Respiration; D012865:Skiing / Q000502:physiology*; D055815:Young Adult
chemical_list: D010100:Oxygen