Physiological Responses in Humans Acutely Exposed to High Altitude (3480 m): Minute Ventilation and Oxygenation Are Predictive for the Development of Acute Mountain Sickness.

The importance of arterial oxygen saturation for the prediction of acute mountain sickness (AMS) is still a matter of debate. Reasons for discrepancies may result from varying laboratory or field conditions and their interactions. Thus, we analyzed data from our prior high-altitude studies, including participants of a broad range of age of both sexes (20 males and 20 females, aged between 20 and 67 years) under strictly standardized conditions of pre-exposure and acute exposure to real high altitude (3480 m). A set of resting cardiovascular, respiratory, hematological, and metabolic variables were recorded at high altitude (Testa Grigia, Plateau Rosa, 3480 m; Swiss-Italian boarder) after performing pretests at low altitude (Innsbruck, 600 m, Austria). Our analyses indicate that (1) smaller changes in resting minute ventilation (VE) and a larger decrease of peripheral oxygen saturation (SpO2) during the first 3 hours of acute exposure to high altitude were independent predictors for subsequent development of AMS (90% correct prediction), (2) there are no differences of responses between sexes, and (3) there is no association of responses with age. Considering the independent effects of both responses (VE and SpO2) may be of clinical/practical relevance. Moreover, the presented data derived from a broad age range of both sexes might be of interest for comparative purposes.