title: Changes in blood gas transport of altitude native soccer players near sea-level and sea-level native soccer players at altitude (ISA3600).
abstract: OBJECTIVE
  The optimal strategy for soccer teams playing at altitude is not known, that is, 'fly-in, fly-out' versus short-term acclimatisation. Here, we document changes in blood gas and vascular volumes of sea-level (Australian, n=20) and altitude (Bolivian, n=19) native soccer players at 3600 m.
  
  
  METHODS
  Haemoglobin-oxygen saturation (Hb-sO₂), arterial oxygen content (CaO₂), haemoglobin mass (Hbmass), blood volume (BV) and blood gas concentrations were measured before descent (Bolivians only), together with aerobic fitness (via Yo-YoIR1), near sea-level, after ascent and during 13 days at 3600 m.
  
  
  RESULTS
  At baseline, haemoglobin concentration [Hb] and Hbmass were higher in Bolivians (mean ± SD; 18.2 ± 1.0 g/dL, 12.8 ± 0.8 g/kg) than Australians (15.0 ± 0.9 g/dL, 11.6 ± 0.7 g/kg; both p ≤ 0.001). Near sea-level, [Hb] of Bolivians decreased to 16.6 ± 0.9 g/dL, but normalised upon return to 3600 m; Hbmass was constant regardless of altitude. In Australians, [Hb] increased after 12 days at 3600 m to 17.3 ± 1.0 g/dL; Hbmass increased by 3.0 ± 2.7% (p ≤ 0.01). BV decreased in both teams at altitude by ∼400 mL. Arterial partial pressure for oxygen (PaO₂), Hb-sO₂ and CaO₂ of both teams decreased within 2 h of arrival at 3600 m (p ≤ 0.001) but increased over the following days, with CaO₂ overcompensated in Australians (+1.7 ± 1.2 mL/100 mL; p ≤ 0.001). Yo-YoIR1 was lower on the 3rd versus 10th day at altitude and was significantly related to CaO₂.
  
  
  CONCLUSIONS
  The marked drop in PaO₂ and CaO₂ observed after ascent does not support the 'fly-in, fly-out' approach for soccer teams to play immediately after arrival at altitude. Although short-term acclimatisation was sufficient for Australians to stabilise their CaO₂ (mostly due to loss of plasma volume), 12 days appears insufficient to reach chronic levels of adaption.
authors.affiliation: Department of Sports Medicine/Sports Physiology, University of Bayreuth, , Bayreuth, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Wachsmuth
authors.forename: Marlen
authors.initials: M
authors.lastname: Kley
authors.forename: Hilde
authors.initials: H
authors.lastname: Spielvogel
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Aughey
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Gore
authors.forename: Pitre C
authors.initials: PC
authors.lastname: Bourdon
authors.forename: Kristal
authors.initials: K
authors.lastname: Hammond
authors.forename: Charli
authors.initials: C
authors.lastname: Sargent
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Roach
authors.forename: Rudy Soria
authors.initials: RS
authors.lastname: Sanchez
authors.forename: Jesus C Jimenez
authors.initials: JC
authors.lastname: Claros
authors.forename: Walter F
authors.initials: WF
authors.lastname: Schmidt
authors.forename: Laura A
authors.initials: LA
authors.lastname: Garvican-Lewis
mesh_terms: D000064:Acclimatization / Q000502:physiology; D000293:Adolescent; D000531:Altitude; D001315:Australia / Q000208:ethnology; D001784:Blood Gas Analysis; D001838:Bolivia / Q000208:ethnology; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008297:Male; D010100:Oxygen / Q000097:blood; D010108:Oxyhemoglobins / Q000378:metabolism; D010313:Partial Pressure; D010809:Physical Fitness / Q000502:physiology; D012916:Soccer / Q000502:physiology*
chemical_list: D006454:Hemoglobins; D010108:Oxyhemoglobins; D010100:Oxygen
keywords: Altitude; Physiology; Respiratory; Soccer