Figure 1. Altitude profile and the sequence of testing sessions for untrained (UT) and trained (T) Caucasians, and for Tibetan lowlanders (Tib 2) and Sherpas (Sh).

Untrained and trained Caucasians underwent control measurements (PRE) at sea level. The same data were adopted also at 1300 m, based on the observation that V̇_O2peak of sedentary subjects is not affected by altitudes below 1500 m (Terrados et al. 1985; Gore et al. 1996). Control measurements (PRE) in Tibetan lowlanders were performed at 1300 m. Experiments were carried out 2–4 (ALT1), 14–16 (ALT2), and 26–28 (ALT3) days after arrival at the Pyramid-Laboratory. At ALT3, Tibetan lowlanders repeated the test also in acute hypobaric normoxia (ALT3-O₂). At altitude, Sherpas underwent experiments only on one occasion (ALT3) and thereafter they were brought and tested at 1300 m (PRE).