Abstract
For practical application, pre-acclimatisation at natural altitude can be effectively achieved through overnight stays above 2000 m or as frequent as possible daytime exposures above 3000 m. In this context, a week of pre-acclimatisation at natural altitude, combined with repeated ascents and descents in the mountains, can be recommended. Overnight stays and repeated exposures of 3–4 h at simulated altitudes above 4000 m are also likely to induce pre-acclimatisation effects and reduce the incidence of acute mountain sickness (AMS). The efficacy of pre-acclimatisation with even shorter hypoxic exposures (approximately 1 h) for AMS prevention remains questionable. As the effects of pre-acclimatisation do not persist for long, it should ideally be carried out within a few days prior to the planned altitude exposure. The optimal or minimal hypoxic dose required to prevent AMS has yet to be determined. Further research is needed to address these outstanding questions.