To present the acclimatization strategy employed by an elite athlete prior to 2 successful ascents to Mount Everest (including a "fastest known time") in 1 wk.
Training volume, training content, and altitude exposure were recorded daily. Vertical velocity was recorded by GPS (global positioning system) heart-rate monitor.
The subject first used a live high-train low and high preacclimatization method in normobaric hypoxia (NH). Daily, he combined sleeping in a hypoxic tent (total hours: ∼260) and exercising "as usual" in normoxia but also in NH (altitude >6000 m: 30 h), including at high intensity. The hypoxic sessions were performed at the second threshold on treadmill in NH at 6000 m, and the pulse saturation increased from 70% to 85% over 1 mo. Then, the subject was progressively exposed to hypobaric hypoxia, first in the Alps and then in the Himalayas. On day 18, he reached for the second time an altitude >8000 m with the fastest vertical velocity (350 m/h) ever measured between 6300 and 8400 m. Afterward, he climbed twice in a week to the summit of Mount Everest (8848 m, including a "fastest known time" of 26.5 h from Rongbuk Monastery, 5100 m).
Overall, this acclimatization was successful and in line with the most recent recommendations: first, using live high-train low and high, and second, using hypobaric hypoxia at increasing altitudes for a better translation of the NH benefits to hypobaric hypoxia. This case study reports the preparation for the most outstanding performance ever acheived at an extreme altitude.