Recovery in normobaric hypoxia as an additional stimulus for high-intensity intermittent training

Objective. - This study aimed to compare the acute physiological responses from hypoxic expo-sure during intervals between efforts performed in high intensity. Methods. - Nine healthy men voluntarily participated in this randomized, single-blind design study. Participants completed two training sessions with ten 1-minute efforts in normoxia [oxy-gen inspired fraction (FiO(2)) = 20.9%] at 120% of the peak speed achieved in a graduated exercise test, followed by 2-minute passive recovery with or without hypoxia (FiO(2) = 13.6%). During the sessions, the physiological responses (heart rate (HR), peripheral oxygen saturation (SpO(2)), blood lactate), the internal and external exercise loads, the hypoxia dose, and the arterial par-tial oxygen pressure (PaO2) were measured. The recorded data were analyzed using a Bayesian statistical approach. Results. - There was no difference between normoxia and hypoxia for blood lactate, internal and external loads. SpO(2) and PaO2 in hypoxia were lower than in normoxia, while HR and dose of hypoxia were higher in hypoxia than in normoxia. Conclusions. - These results demonstrate that exposure to hypoxia in the intervals between efforts can be an additional stimulus to training without impairing the external load and the quality of the training sessions. Published by Elsevier Masson SAS.