Characterisation of the acute hypoxic response using breathing variability parameters: A pilot study in humans

•We exposed participants to normobaric hypoxia of increasing severity (i.e., simulating 2200m, 4000m, 5000m) at rest while recording respiratory rate, tidal volume, and SpO2.•Higher respiratory rate variability is independently associated with lower SpO2 during acute hypoxic exposure, while tidal volume variability parameters are not.•Respiratory rate variability may be a potentially interesting parameter to characterize individual responses to acute hypoxia.