This study investigated if six-weeks intermittent hypoxic training (IHT) – designed to avoid reductions in training loads and intensities – improves endurance performance capacity of competitive distance runners.

18 athletes were assigned to either normoxia or intermittent hypoxia. Both before and after training, the athletes’ VO2max at sea level and in hypoxia was determined, alongside other physiological markers of endurance performance.

Only the athletes in the hypoxic training group improved VO2 max, as well as time to exhaustion. Those training in the normoxic group did not display any similar improvements.

This suggests IHT of HIIT and moderate duration hypoxic sessions may result in gains in trained athletes in the guise of muscular adaptations leading to increased endurance performance capacity.