Original Article

European Journal of Applied Physiology

, Volume 112, Issue 9, pp 3287-3294

First online:

Acclimatisation in trekkers with and without recent exposure to high altitude

  • Meaghan J. MacNuttAffiliated withHealth and Integrative Physiology Laboratory, School of Kinesiology, University of British Columbia Email author 
  • , Paul B. LaursenAffiliated withHigh Performance Sport New ZealandSport Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of TechnologySchool of Exercise, Biomedical and Health Sciences, Edith Cowan University
  • , Shiksha KediaAffiliated withMountain Medicine Society of Nepal
  • , Maniraj NeupaneAffiliated withMountain Medicine Society of Nepal
  • , Parash ParajuliAffiliated withMountain Medicine Society of Nepal
  • , Jhapindra PokharelAffiliated withMountain Medicine Society of Nepal
  • , A. William SheelAffiliated withHealth and Integrative Physiology Laboratory, School of Kinesiology, University of British Columbia

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In mountaineers, recent altitude exposure has been shown to improve climbing performance and clinical outcomes during re-exposure to high altitude. However, the timing of previous altitude exposure has not been clearly reported and previous findings might be driven by individuals who were still acclimatised at the time of re-exposure. Our goal was to determine whether recent altitude exposure would confer an advantage even in individuals who had de-acclimatised for ≥1 week before being re-exposure. Low-altitude natives kept a daily trekking log throughout 7- to 8-day trek from Lukla (2,840 m) to Gokyo Ri (5,360 m). Trekkers with recent altitude exposure (re-acclimatisers, RA; n = 20) walked 20% faster (p < 0.01), reported lower acute mountain sickness scores (9 ± 8 vs. 15 ± 13; p = 0.02), and used less medication to treat headache (p < 0.05) compared to trekkers with no recent altitude exposure (initial acclimatisers, IA; n = 30). On Gokyo Ri, SpO2 was significantly higher in RA than IA trekkers (85 ± 6 vs. 78 ± 6; p = 0.01). These data indicate improved functional outcomes and physiological compensation for hypoxia in RA. However, even after de-acclimatisation for 7–30 days, it is possible that RA trekkers began the trek in a more acclimatised state than IA trekkers. RA trekkers might represent a self-selected group that has previously tolerated altitude well and has therefore opted to return. Some findings might also reflect improved psychological altitude tolerance in RA. A direct comparison of the functional and physiological responses to hypoxia throughout an initial and re-acclimatisation to high altitude is needed.


Hypoxia Pre-exposure Re-exposure De-acclimatisation Re-acclimatisation Altitude tolerance