title: Influence of blood donation on the incidence of plateau at VO2max.
abstract: OBJECTIVE
  The purpose of this study was to examine the effects of reductions in blood volume and associated oxygen-carrying capacity on the incidence of plateau at VO2max.
  
  
  METHODS
  Fifteen well-trained athletes (age 23.3 ± 4.5; mass 77.4 ± 13.1 kg, height 180.1 ± 6.0 cm) completed three incremental cycle tests to volitional exhaustion, of which the first was defined as familiarisation, with the remaining two trials forming the experimental conditions of pre- (UBL) and post-(BLE) blood donation (~ 450 cm(3)). The work rate for the incremental tests commenced at 100 W for 60 s followed by a ramp of 0.42 W s(-1), with cadence being held constant at 80 rpm. Throughout all trials, VO2 was determined on a breath-by-breath basis using a pre-calibrated metabolic cart. The criteria for plateau determination was a ∆VO2 ≤ 50 ml min(-1) over the final two consecutive 30 s sampling periods.
  
  
  RESULTS
  Despite a significant (P = 0.0028) 9.4 % reduction in haemoglobin concentration and 10.8 % (P = 0.016) reduction in erythrocyte count between UBL and BLE, there was no change in plateau incidence. However, significant differences were observed for both VO2max (P = 0.0059) 51.3 ± 7.6 (UBL) 48.4 ± 7.9 ml kg(-1) min(-1) (BLE) and gas exchange threshold arrival time 383.4 ± 85.2 s (UBL) 349.2 ± 71.4 s (BLE) (P = 0.0028).
  
  
  CONCLUSIONS
  These data suggest that plateau at VO2max is unaffected by O2 availability lending support to the notion of the plateau being dependent on the anaerobic capacity and the classically orientated concept of VO2max.
authors.forename: Dan
authors.initials: D
authors.lastname: Gordon
authors.forename: Madeleine
authors.initials: M
authors.lastname: Wood
authors.forename: Andrew
authors.initials: A
authors.lastname: Porter
authors.forename: Vignesh
authors.initials: V
authors.lastname: Vetrivel
authors.forename: Marie
authors.initials: M
authors.lastname: Gernigon
authors.forename: Oliver
authors.initials: O
authors.lastname: Caddy
authors.forename: Viviane
authors.initials: V
authors.lastname: Merzbach
authors.forename: Don
authors.initials: D
authors.lastname: Keiller
authors.forename: James
authors.initials: J
authors.lastname: Baker
authors.forename: Richard
authors.initials: R
authors.lastname: Barnes
mesh_terms: D000328:Adult; D015308:Anaerobic Threshold; D001782:Blood Donors; D001810:Blood Volume; D015444:Exercise; D006801:Humans; D008297:Male