Incremental ascent to 4300 m does not alter standing balance in lowlanders or Tibetan highlanders

We investigated the influence of incremental ascent to 4300 m on standing balance under eyes open and eyes closed conditions in lowlanders and Tibetan highlanders (e.g., Sherpa).

29 healthy participants, that included 15 lowlanders (LL, 7 M, 8F; 22.4 ± 3.0 years) and 14 Tibetan highlanders (TH; 7 M,7F, 22.9 ± 4.5 years) completed this study. Unacclimatized participants performed two 90-s standing balance trials on a force plate with eyes open and eyes closed, at low altitude (1400 m) and after 5 days of incremental ascent to high altitude (4300 m). Center of pressure (CoP) velocity and standard deviation were calculated to quantify postural sway. Peripheral blood oxygen saturation (SpO₂) was continuously monitored during standing balance trials.

SpO₂ was significantly lower at high altitude compared to low altitude (P < 0.0001). We did not find significant changes in COP velocity amplitude or standard deviation between low and high altitude for all participants, or when comparing LL and TH, or males and females, in either the eyes open or eyes closed conditions (P > 0.1532). TH had significantly greater CoP velocity compared to LL with eyes open (P= 0.0090). Males had significantly greater sway velocity than females with eyes closed (P = 0.0193).

These findings suggest that incremental ascent to 4300 m does not change standing balance in LL and TH. This finding contradicts previous studies that found standing balance to be impaired at high altitude. Future work is needed to investigate the influence of high altitude trekking models and acclimatization on standing balance.