title: Effects of oxygen supplementation on acute mountain sickness symptoms and functional capacity during a 2-kilometer walk test on Chajnantor plateau (5050 meters, Northern Chile).
abstract: OBJECTIVE
  The aim of this study was to test the hypothesis that administration of low-flow oxygen will improve physical performance in subjects unacclimatized to altitude. We evaluated the effects of oxygen supplementation on functional capacity and acute mountain sickness (AMS) symptoms in young, healthy male and female subjects who performed a 2-km fast walk test following rapid ascent to the Chajnantor plateau (5050 m above sea level) in Northern Chile.
  
  
  METHODS
  The participants were randomly distributed into 2 groups according to oxygen supplementation levels: 1 or 3 L O(2) · min(-1). Within each group, males and females were evaluated separately. A preliminary walk test was carried out at sea level on a 100-m long, flat track with 10 U-turns. For the first walk at altitude, subjects carried the supplementary oxygen system but did not breathe the oxygen. Subjects received oxygen through a facemask the following day during the second test. The nights prior to altitude tests were spent at 2400 m in San Pedro de Atacama.
  
  
  RESULTS
  Supplementary oxygen administration during a 2-km walk test significantly improved walking times at 5050 m. We also observed a significant improvement in AMS symptoms. As expected, however, performance was poorer at altitude compared to test values at sea level, despite supplementary oxygen administration.
  
  
  CONCLUSIONS
  Our findings demonstrate the beneficial effects of supplementary oxygen administration on physical capacity, reducing the incidence of AMS and, thus, improving health and safety conditions for high altitude workers following rapid ascent, when adequate acclimatization is not possible.
authors.affiliation: Unidad de Fisiología, Departamento Biomédico, Facultad de Ciencias de la Salud, Universidad de Antofagasta, Antofagasta, Chile.
authors.forename: Juan A
authors.initials: JA
authors.lastname: Silva-Urra
authors.forename: Constanza
authors.initials: C
authors.lastname: Urizar
authors.forename: Carla
authors.initials: C
authors.lastname: Basualto-Alarcón
authors.forename: Joan Ramon
authors.initials: JR
authors.lastname: Torrella
authors.forename: Teresa
authors.initials: T
authors.lastname: Pagés
authors.forename: Claus
authors.initials: C
authors.lastname: Behn
authors.forename: Ginés
authors.initials: G
authors.lastname: Viscor
mesh_terms: D000064:Acclimatization; D000532:Altitude Sickness / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D009051:Mountaineering; D010100:Oxygen / Q000008:administration & dosage*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D010100:Oxygen