Abstract

We test the hypothesis that breathing oxygen-enriched air (FIO2=100%) maintains exercise performance and reduces fatigue during intervals of maximal-intensity cycling. Ten well-trained male cyclists (age 25+3 years; peak oxygen uptake 64.8+6.2 ml _ kg–1 _ min–1; mean+s) were exposed to either hyperoxic or normoxic air during the 6-min intervals between five 30-s sessions of cycling at maximal intensity. The concentrations of lactate and hydrogen ions [Hþ], pH, base excess, oxygen partial pressure, and oxygen saturation in the blood were assessed before and after these sprints. The peak (P=0.62) and mean power outputs (P=0.83) with hyperoxic and normoxic air did not differ. The partial pressure of oxygen was 4.2- fold higher after inhaling hyperoxic air, whereas lactate concentration, pH, [Hþ], and base excess (P_0.17) were not influenced. Perceived exertion towards the end of the 6-min periods after the fourth and fifth sprints (P50.05) was lower with hyperoxia than normoxia (P50.05). These findings demonstrate that the peak and mean power outputs of athletes performing intervals of maximal-intensity cycling are not improved by inhalation of oxygen-enriched air during recovery. Verf.-Referat