title: Similar Hemoglobin Mass Response in Hypobaric and Normobaric Hypoxia in Athletes.
abstract: OBJECTIVE
  To compare hemoglobin mass (Hb(mass)) changes during an 18-d live high-train low (LHTL) altitude training camp in normobaric hypoxia (NH) and hypobaric hypoxia (HH).
  
  
  METHODS
  Twenty-eight well-trained male triathletes were split into three groups (NH: n = 10, HH: n = 11, control [CON]: n = 7) and participated in an 18-d LHTL camp. NH and HH slept at 2250 m, whereas CON slept, and all groups trained at altitudes <1200 m. Hb(mass) was measured in duplicate with the optimized carbon monoxide rebreathing method before (pre-), immediately after (post-) (hypoxic dose: 316 vs 238 h for HH and NH), and at day 13 in HH (230 h, hypoxic dose matched to 18-d NH). Running (3-km run) and cycling (incremental cycling test) performances were measured pre and post.
  
  
  RESULTS
  Hb(mass) increased similar in HH (+4.4%, P < 0.001 at day 13; +4.5%, P < 0.001 at day 18) and NH (+4.1%, P < 0.001) compared with CON (+1.9%, P = 0.08). There was a wide variability in individual Hb(mass) responses in HH (-0.1% to +10.6%) and NH (-1.4% to +7.7%). Postrunning time decreased in HH (-3.9%, P < 0.001), NH (-3.3%, P < 0.001), and CON (-2.1%, P = 0.03), whereas cycling performance changed nonsignificantly in HH and NH (+2.4%, P > 0.08) and remained unchanged in CON (+0.2%, P = 0.89).
  
  
  CONCLUSIONS
  HH and NH evoked similar Hb(mass) increases for the same hypoxic dose and after 18-d LHTL. The wide variability in individual Hb(mass) responses in HH and NH emphasizes the importance of individual Hb(mass) evaluation of altitude training.
authors.affiliation: 1Section for Elite Sport, Swiss Federal Institute of Sport, Magglingen, SWITZERLAND; 2Department of Physiology, Faculty of Biology and Medicine, ISSUL, Institute of Sport Sciences, University of Lausanne, SWITZERLAND; 3National School of Mountain Sports/National Ski-Nordic Centre, Prémanon, FRANCE; 4Departmental Section of Physical Education and Sports, University of Alicante, SPAIN; and 5Swiss Laboratory for Doping Analyses, University Center of Legal Medicine, Geneva & Lausanne, Center Hospitalier Universitaire Vaudois & University of Lausanne, SWITZERLAND.
authors.forename: Anna
authors.initials: A
authors.lastname: Hauser
authors.forename: Laurent
authors.initials: L
authors.lastname: Schmitt
authors.forename: Severin
authors.initials: S
authors.lastname: Troesch
authors.forename: Jonas J
authors.initials: JJ
authors.lastname: Saugy
authors.forename: Roberto
authors.initials: R
authors.lastname: Cejuela-Anta
authors.forename: Raphael
authors.initials: R
authors.lastname: Faiss
authors.forename: Neil
authors.initials: N
authors.lastname: Robinson
authors.forename: Jon P
authors.initials: JP
authors.lastname: Wehrlin
authors.forename: Grégoire P
authors.initials: GP
authors.lastname: Millet
mesh_terms: D000328:Adult; D000531:Altitude; D056352:Athletes; D054874:Athletic Performance; D001642:Bicycling / Q000502:physiology*; D005080:Exercise Test; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D000860:Hypoxia / Q000097:blood*; D008297:Male; D012420:Running / Q000502:physiology*; D055815:Young Adult
chemical_list: D006454:Hemoglobins