Effects of increasing oxygen availability on bicycle ergometer endurance performance.

Abstract

In order to test the effects of increasing oxygen availability on bicycle ergometer endurance performance, 26 subjects completed two criterion endurance performance tests of 6'min duration, (designed to elicit 115% of [Vdot]O2max) while breathing either room air or 100% oxygen. It was hypothesised that if oxygen availability is a limiting factor in endurance performance, one would expect increased work output in the hyperoxic condition, Hyperoxic conditions that do not result in increased work performance would support the cell as limiting. The results of the present study support the oxygen transport theory as the major limiting factor in aerobic endurance performance. Subjects turned substantially more pedal revolutions (17[sdot]3 revs :p < 0[sdot]01) and had significantly higher oxygen uptakes (650 to 780 cm3 greater: p < 0[sdot]01) in the 100% oxygen condition. In addition, there were no differences in estimated cardiac output between the two conditions while there were substantial differences in the estimated a-v O2 difference (2[sdot]92 cm3 100 cm−3 higher in 100% oxygen, p < 0[sdot]01). The increase in work performance was, therefore, ascribed to increased cellular availability of oxygen during hyperoxia.