title: Blood volume and hemoglobin mass in endurance athletes from moderate altitude.
abstract: OBJECTIVE
  To determine whether total hemoglobin (tHb) mass and total blood volume (BV) are influenced by training, by chronic altitude exposure, and possibly by the combination of both conditions.
  
  
  METHODS
  Four groups (N = 12, each) either from locations at sea level or at moderate altitude (2600 m) were investigated: 1) sea-level control group (UT-0 m), 2) altitude control group (UT-2600 m), 3) professional cyclists from sea level (C-0 m), and 4) professional cyclists from altitude (C-2600 m). All subjects from altitude were born at about 2600 m and lived all their lives (except during competitions at lower levels) at this altitude. tHb and BV were determined by the CO-rebreathing method.
  
  
  RESULTS
  VO2max (mL x kg(-1) x min(-1)) was significantly higher in UT-0 m (45.3 +/- 3.2) than in UT-2600 m (39.6 +/- 4.0) but did not differ between C-0 m (68.2 +/- 2.7) and C-2600 m (69.9 +/- 4.4). tHb (g x kg(-1)) was affected by training (UT-0 m: 11.0 +/- 1.1, C-0 m: 15.4 +/- 1.3) and by altitude (UT-2600 m: 13.4 +/- 0.9) and showed both effects in C-2600 m (17.1 +/- 1.4). Because red cell volume showed a behavior similar to tHb and because plasma volume was not affected by altitude but by training, BV (mL x kg(-1)) was increased in C-0 m (UT-0 m: 78.3 +/- 7.9; C-0 m: 107.0 +/- 6.2) and in UT-2600 m (88.2 +/- 4.8), showing highest values in the C-2600 m group (116.5 +/- 11.4).
  
  
  CONCLUSIONS
  In endurance athletes who are native to moderate altitude, tHb and BV were synergistically influenced by training and by altitude exposure, which is probably one important reason for their high performance.
authors.affiliation: Dept. of Sports Medicine and Sports Physiology, University of Bayreuth, 95440 Bayreuth, Germany. walter.schmidt@uni-bayreuth.de
authors.forename: Walter
authors.initials: W
authors.lastname: Schmidt
authors.forename: Katja
authors.initials: K
authors.lastname: Heinicke
authors.forename: Joel
authors.initials: J
authors.lastname: Rojas
authors.forename: Jose
authors.initials: J
authors.lastname: Manuel Gomez
authors.forename: Mauricio
authors.initials: M
authors.lastname: Serrato
authors.forename: Mercedes
authors.initials: M
authors.lastname: Mora
authors.forename: Bernd
authors.initials: B
authors.lastname: Wolfarth
authors.forename: Andreas
authors.initials: A
authors.lastname: Schmid
authors.forename: Joseph
authors.initials: J
authors.lastname: Keul
mesh_terms: D000328:Adult; D000531:Altitude; D015415:Biomarkers / Q000097:blood; D001810:Blood Volume / Q000502:physiology*; D001823:Body Composition / Q000502:physiology; D001824:Body Constitution / Q000502:physiology; D015992:Body Mass Index; D003105:Colombia; D004920:Erythropoiesis / Q000502:physiology; D005858:Germany; D006400:Hematocrit; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D010807:Physical Endurance / Q000502:physiology*; D011990:Receptors, Transferrin / Q000378:metabolism; D013177:Sports
chemical_list: D015415:Biomarkers; D006454:Hemoglobins; D011990:Receptors, Transferrin