Figure 1.

Partial pressure of inspired oxygen (PiO2) as a percentage of sea-level values at increasing altitudes. Altitudes at which participants were recruited in this study (500 m, 2,500 m, > 3,650 m) and in other studies (A: Burg et al.²², at 1,600 m; B: Coote et al.¹⁹, Spicuzza et al.²⁰, at 4,380 m) are shown. The solid line represents inspired oxygen in mmHg (left hand y axis) and the dashed line represents percent of inspired oxygen compared to sea-level values (right hand y axis). Figure adapted from: Beall et al.⁷ Copyright (2007) National Academy of Sciences, USA.