Effect Of Training Under Hyperoxia On Exercise Performance And Aerobic Capacity In Trained Cyclists

Abstract

Some previous studies suggested that trained athletes can perform exercise at high power outputs and long duration during inspiration of a hyperoxic gas mixture, which would inhibit the decrease in arterial oxygen saturation (SpO2) levels during intense exercise. Training under hyperoxia could increase aerobic capacity, and thus improve exercise performance in trained athletes. PURPOSE: This study aimed to determine the effect of training under hyperoxia on exercise performance and aerobic capacity in trained cyclists. METHODS: Six male trained cyclists (age: 21.3 ± 1.9 yr, height: 168.6 ± 5.5 cm, weight: 59.7 ± 9.0 kg) performed training under hyperoxia. Before the training periods (pre-training), the subjects performed an incremental exercise test to exhaustion in which the work rate at initiation was 120 W for 3 min. The work rate was then increased as a step function by 40 W every 3 min at a pedal rate of 90 rpm to determine the workload corresponding to the maximal oxygen uptake (VO2max) and work rate max (WRmax) by using a bicycle ergometer. VO2max was determined by calculating the average of the breath–by–breath data over 30-s intervals during the incremental test. All the subjects underwent training under hyperoxia on 3 days per week for a 4-weeks period. The training protocol consisted of 5 repetitions of intense exercise at 3–min intervals. The intensity of the intense exercise was 90–100% WRmax. The duration of the intense exercise was 3 min in sets of 1–4, and the subjects cycled to voluntary exhaustion in 5 sets. All the subjects completed the training under conditions of hyperoxic gas mixture (36.1–37.2% O2). They also performed the incremental exercise test 3–6 days after the training periods (post-training). RESULTS: The time required by the subjects to perform the incremental exercise test in the post-training period was significantly longer than that required in the pre-training period (16.69 ± 1.64 min vs. 15.81 ± 2.22 min; p = 0.022). There were no statistically significant differences in VO2max between the post-training period and the pre-training period (57.2 ± 6.0 ml min-1 vs. 56.2 ± 6.6 ml min-1). CONCLUSION: Our results showed that submaximal training with inspiration of a hyperoxic gas mixture for 4 weeks improves exercise performance in trained cyclists.