title: Effect of 3-week high-intensity interval training on VO2max, total haemoglobin mass, plasma and blood volume in well-trained athletes.
abstract: OBJECTIVE
  This study examined the haematological adaptations to high-intensity interval training (HIT), i.e. total haemoglobin mass (tHb-mass), blood volume (BV), and plasma volume (PV), and its effects on VO2max in well-trained athletes.
  
  
  METHODS
  Twenty-seven male and eight female well-trained (VO2max 63.7 ± 7.7 ml/min/kg) athletes were randomly assigned to the HIT (HITG, N = 19) or the control group (CG, N = 16). Over a 3-week period, the HITG performed 11 HIT sessions, consisting of four 4-min interval bouts at an exercise intensity of 90-95 % of the individual maximal heart rate (HRmax), separated by 4-min active recovery periods. Before and 5 ± 2 days after the intervention, tHb-mass, BV and PV were determined by the CO-rebreathing method. VO2max was assessed in a laboratory treadmill test.
  
  
  RESULTS
  tHb-mass (from 753 ± 124 to 760 ± 121 g), BV (from 5.6 ± 0.8 to 5.6 ± 0.9 l) and PV (from 3.2 ± 0.5 to 3.2 ± 0.5 l) remained unchanged after HIT and did not show an interaction (group × time). Within the HITG, VO2max improved from baseline by +3.5 % (p = 0.011), but remained unchanged in the CG. No interaction (group × time) was seen for VO2max. The HITG showed a significant reduction in HRmax compared to the baseline measurement (-2.3 %, p ≤ 0.001), but HRmax remained unchanged in the CG. There was a significant interaction (group × time) for HRmax (p = 0.006). Also, oxygen pulse significantly increased only in HITG from 22.9 ± 4.4 to 23.9 ± 4.2 ml/beat, with no interaction (p = 0.150).
  
  
  CONCLUSIONS
  Eleven HIT sessions added to usual training did neither improve VO2max nor haematological parameters compared to the CG.
authors.affiliation: Medical Section, Department of Sport Science, University Innsbruck, Fürstenweg 185, 6020, Innsbruck, Austria. verena.menz@student.uibk.ac.at.
authors.forename: Verena
authors.initials: V
authors.lastname: Menz
authors.affiliation: Medical Section, Department of Sport Science, University Innsbruck, Fürstenweg 185, 6020, Innsbruck, Austria.
authors.forename: Jochen
authors.initials: J
authors.lastname: Strobl
authors.affiliation: Medical Section, Department of Sport Science, University Innsbruck, Fürstenweg 185, 6020, Innsbruck, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Faulhaber
authors.affiliation: Medical Section, Department of Sport Science, University Innsbruck, Fürstenweg 185, 6020, Innsbruck, Austria.
authors.forename: Hannes
authors.initials: H
authors.lastname: Gatterer
authors.affiliation: Medical Section, Department of Sport Science, University Innsbruck, Fürstenweg 185, 6020, Innsbruck, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Burtscher
mesh_terms: D000328:Adult; D056352:Athletes; D001810:Blood Volume / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D064797:Physical Conditioning, Human / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D055815:Young Adult
chemical_list: D006454:Hemoglobins
keywords: Blood volume; High-intensity interval training; Maximal oxygen uptake; Plasma volume; Total haemoglobin mass; Well-trained individuals