TY - JOUR
T1 - Influence of hyperoxia on pulmonary O2 uptake kinetics following the onset of exercise in humans
AU - Wilkerson, Daryl P.
AU - Berger, Nicolas
AU - Jones, Andrew M.
PY - 2006/8/1
Y1 - 2006/8/1
N2 - The purpose of this study was to examine the influence of hyperoxic gas (50% O2 in N2) inspiration on pulmonary oxygen uptake (over(V, ̇)O2) kinetics during step transitions to moderate, severe and supra-maximal intensity cycle exercise. Seven healthy male subjects completed repeat transitions to moderate (90% of the gas exchange threshold, GET), severe (70% of the difference between the GET and over(V, ̇)O2 peak) and supra-maximal (105% over(V, ̇)O2 peak) intensity work rates while breathing either normoxic (N) or hyperoxic (H) gas before and during exercise. Hyperoxia had no significant effect on the Phase II over(V, ̇)O2 time constant during moderate (N: 28 ± 3 s versus H: 31 ± 7 s), severe (N: 32 ± 9 s versus H: 33 ± 6 s) or supra-maximal (N: 37 ± 9 s versus H: 37 ± 9 s) exercise. Hyperoxia resulted in a 45% reduction in the amplitude of the over(V, ̇)O2 slow component during severe exercise (N: 0.60 ± 0.21 L min-1 versus H: 0.33 ± 0.17 L min-1; P < 0.05) and a 15% extension of time to exhaustion during supra-maximal exercise (N: 173 ± 28 s versus H: 198 ± 41 s; P < 0.05). These results indicate that the Phase II over(V, ̇)O2 kinetics are not normally constrained by (diffusional) O2 transport limitations during moderate, severe or supra-maximal intensity exercise in young healthy subjects performing upright cycle exercise.
AB - The purpose of this study was to examine the influence of hyperoxic gas (50% O2 in N2) inspiration on pulmonary oxygen uptake (over(V, ̇)O2) kinetics during step transitions to moderate, severe and supra-maximal intensity cycle exercise. Seven healthy male subjects completed repeat transitions to moderate (90% of the gas exchange threshold, GET), severe (70% of the difference between the GET and over(V, ̇)O2 peak) and supra-maximal (105% over(V, ̇)O2 peak) intensity work rates while breathing either normoxic (N) or hyperoxic (H) gas before and during exercise. Hyperoxia had no significant effect on the Phase II over(V, ̇)O2 time constant during moderate (N: 28 ± 3 s versus H: 31 ± 7 s), severe (N: 32 ± 9 s versus H: 33 ± 6 s) or supra-maximal (N: 37 ± 9 s versus H: 37 ± 9 s) exercise. Hyperoxia resulted in a 45% reduction in the amplitude of the over(V, ̇)O2 slow component during severe exercise (N: 0.60 ± 0.21 L min-1 versus H: 0.33 ± 0.17 L min-1; P < 0.05) and a 15% extension of time to exhaustion during supra-maximal exercise (N: 173 ± 28 s versus H: 198 ± 41 s; P < 0.05). These results indicate that the Phase II over(V, ̇)O2 kinetics are not normally constrained by (diffusional) O2 transport limitations during moderate, severe or supra-maximal intensity exercise in young healthy subjects performing upright cycle exercise.
UR - http://www.scopus.com/inward/record.url?scp=33746836554&partnerID=8YFLogxK
U2 - 10.1016/j.resp.2005.09.006
DO - 10.1016/j.resp.2005.09.006
M3 - Article
C2 - 16309978
AN - SCOPUS:33746836554
SN - 1569-9048
VL - 153
SP - 92
EP - 106
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
IS - 1
ER -