Simulated moderate hypoxia reduces intermittent sprint performance in games players

BACKGROUND: Exercise at altitude places additional physiological stress on the individual in comparison with sea-level performance. This study examines the effect of a moderate hypoxic environment (FiO2=~17%) on intermittent sprint exercise performance. METHODS: Nine male games players completed two consecutive sets of a 40 minute cycling intermittent sprint protocol (CISP×2) in a hypoxic (HYP; FiO2=~17%) and normoxic (NORM; FiO2=~21%) environment. During each sprint peak power output (PPO; the highest power during each 5 s sprint), mean power output (MPO; the average power during the 3 s sprint) were measured and total work done (WD; force applied from the highest 3 s period of power output) was calculated. Physiological responses were recorded throughout the testing procedure. RESULTS: Reductions were found in PPO (944±155 vs. 983±167 W), MPO (900±176 vs. 853±177 W) and WD (102±20 vs. 108±20 kJ) during the CISP×2 (P<0.05) at HYP compared to NORM. Reductions in PPO, MPO and WD were also found between the 1st half and 2nd half CISP (P<0.05) and there was a greater decline from the 1st half CISP to the 2nd half CISP in PPO, MPO and WD at HYP. Heart rate was higher and peripheral arterial oxygen saturation lower during HYP compared to NORM (P<0.05). CONCLUSION: Moderate hypoxia significantly reduced PPO (~4%), MPO (~5%) and WD (~5%) compared to normoxia. The results suggest athletes will be at a disadvantage when performing intermittent sprinting at moderate altitude