Ogura, Y., Katamoto, S., Uchimaru, J., Naito, H., & Aoki, J. (2005). Effects of different levels of hypoxia on anaerobic energy release during supramaximal exercise in trained athletes. Medicine and Science in Sports and Exercise, 37(5), Supplement abstract 1552.

Males (N = 7) performed 12 submaximal cycling-economy tests to establish the relationship between submaximal workload and O2 uptake. Ss then performed three 40-second Wingate tests under 20.9, 16.4, and 12.8% O2 conditions.

No significant differences between the three conditions were observed in pedal frequency, power output, and estimated O2 demand. Oxygen uptake was significantly lower in the 12.8% condition in the 21-30-second interval when compared to the 20.9% condition. The percent anaerobic energy release was significantly lower in 21-30 and 31-40-second intervals in the 12.8% condition when compared to the 20.9% condition.

Implication. Severe hypoxia stimulated a significant increase of hypoxia-induced anaerobic energy release during supramaximal exercise. Perhaps there is an "hypoxic threshold" below which the ambient O2 concentration has to fall for a significant increase in anaerobic energy to occur.

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