One of the major challenges in adapting to high altitudes is that with increasing altitude sleeping quality declines rapidly. Thus, the night sleep can only provide limited to none regeneration. It usually takes a prolonged stay at a constant altitude to adapt sufficiently to the altitude and to have a refreshing night sleep. 1975 Reit et. al showed in their EEG-recordings that the sleep architecture (the regular succession of the particular sleep phases) is disturbed by repeating arousals which occur due to an irregularity in the breathing rhythm.