Résumé
This study focuses on the effect of hyperoxia on maximal oxygen uptake ( ifmmode expandafter else . expandafter Unknown character . fi V O 2 max ) and maximal power (Pmax) in subjects exhibiting exercise-induced arterial hypoxemia (EIH) at sea level. Sixteen competing male cyclists ifmmode expandafter else . expandafter Unknown character . fi V O 2 max >60ml.min super(-1) .kg super(-1)) performed exhaustive ramp exercise (cycle-ergometer) under normoxia and moderate hyperoxia (FIO sub(2)=30%). After the normoxic trial, the subjects were divided into those demonstrating EIH during exercise [arterial O sub(2) desaturation ( Delta SaO sub(2)) >5%; n=9] and those who did not (n=7). Under hyperoxia, SaO sub(2) raised and the increase was greater for the EIH than for the non-EIH group (P<0.001). ifmmode expandafter else . expandafter Unknown character . fi V O 2 max improved for both groups and to a greater extent for EIH (12.8 plus or minus 5.7% vs. 4.2 plus or minus 4.6%, P<0.01; mean plus or minus SD) and the increase was correlated to the gain in SaO sub(2) for all subjects (r=0.71, P<0.01). Pmax improved by 3.3 plus or minus 3.3% (P<0.01) regardless of the group. These data suggest that pulmonary gas exchange contributes to a limitation in ifmmode expandafter else . expandafter Unknown character . fi V O 2 max and power for especially EIH subjects.