ABSTRACT
On May 8, 1978, Reinhold Messner and Peter Habeler became the first humans to summit Mt. Everest without the use of supplementary oxygen, thus achieving what many physiologists had believed to be impossible because sudden exposure to air with an oxygen concentration as on the summit of Mt. Everest results in unconsciousness within minutes, and if continued, death (2). Indeed, it was well known that capacity for exercise performance is progressively limited with increasing altitude (Fig. 1). Since the first ascent ‘‘by fair means’’ in 1978, several others, includ-
Figure 1 The decrease in V˙ o2 max as a function of altitude expressed in % of sea level control. Open symbols are acute hypoxic exposure and closed symbols chronic exposure.
