title: The influence of inspired oxygen on the oxygen uptake response to ramp exercise.
abstract: The relation between VO2 and work rate (WR) was examined in seven male subjects who performed ramp (1 W.3s-1) two-legged cycle ergometry to exhaustion while inspiring either hypoxic (12% O2), normoxic (21% O2), or hyperoxic (40% O2) air. The anaerobic threshold was estimated from respiratory gas exchange threshold (RGET). Prior to the RGET, the delta VO2/delta WR was greater under normoxic [mean (SD); 10.19(1.04) ml O2.min-1.W-1] and hyperoxic [10.44 (0.72)] conditions compared with hypoxia [9.34 (0.89)]. Above the RGET, the delta VO2/delta WR for hypoxia [8.91 (0.63)], normoxia [10.40 (0.77)], and hyperoxia [11.08 (0.48)] were all significantly different from each other. These data indicated that for two-legged, cycle, ramp ergometry in normoxia below the RGET, both the delta VO2/delta WR and response time was constant. Above the RGET, the normoxic VO2 response was the net result of a declining delta VO2/delta WR and a longer response time to the unsteady state character of a ramp exercise protocol.
authors.affiliation: School of Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: M L
authors.initials: ML
authors.lastname: Walsh
authors.forename: E W
authors.initials: EW
authors.lastname: Banister
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D010100:Oxygen / Q000008:administration & dosage*; D010101:Oxygen Consumption / Q000502:physiology*; D011659:Pulmonary Gas Exchange; D012119:Respiration
chemical_list: D010100:Oxygen