Introduction: Repeated short-term exposures to a severe degree of hypoxia, alternated with similar intervals of normoxia, are recommended for performance enhancement in sports. However, scientific evidence for the efficiency of this method is controversial with regard to anaerobic performance. Therefore, we conducted a randomized, double-blind, placebo-controlled study to investigate the effects of this new method on both anaerobic and aerobic performance.
Methods: During 15 consecutive days, 20 endurance-trained men (V O2max (mean +/- SD) 60.2 +/- 6.8 mL x kg(-1) x min(-1)) were exposed each day to breathing (through mouthpieces) either a gas mixture (11% O2 on days 1-7 and 10% O2 on days 8-15; hypoxia group, N = 10) or compressed air (control group, N = 10), six times for 6 min, followed by 4 min of breathing room air for a total of six consecutive cycles. Before and after the treatment, an incremental cycle ergometer test to exhaustion and the Wingate anaerobic test were performed to assess aerobic and anaerobic performance.
Results: Hypoxic treatment did not improve peak power or mean power during the Wingate anaerobic test, nor did it affect maximal oxygen uptake (V O2max), maximal power output (Pmax), lactate threshold or levels of heart rate (HR), minute ventilation (V E), oxygen uptake (V O2), or blood lactate concentration at the submaximal workloads during the ergometer test. Maximal lactate concentration (Lamax) after the tests and HRmax and maximal respiratory exchange ratio (RERmax) during the ergometer test were not significantly different between groups at any time.
Conclusion: The results of this study demonstrated that 1 h of intermittent hypoxic exposure for 15 consecutive days has no effect on aerobic or anaerobic performance.