Details

Autor(en) / Beteiligte

• Hoshikawa, Masako
• Hashimoto, Shiori
• Kawahara, Takashi
• Ide, Rika

Titel

Postural instability at a simulated altitude of 5,000m before and after an expedition to Mt. Cho-Oyu (8,201m)

Ist Teil von

• European journal of applied physiology, 2010-10, Vol.110 (3), p.539-547

Erscheinungsjahr

2010

Quelle

Springer Journals

Beschreibungen/Notizen

• To clarify the effects of altitude acclimatization on postural instability at altitudes, six female climbers stood with their eyes open or closed on a force-measuring platform under normoxia (NC) and hypobaric hypoxia, equivalent to a 5,000m altitude (HC), before and after an expedition to Mt. Cho-Oyu (8,201m). The expedition extended over 84days. We recorded sways in the center of foot pressure, electromyograms (EMGs) of lower-leg muscles, blood components and arterial oxygen saturation (SpO sub(2)). Before the expedition, the maximum amplitude of sway with the eyes open and integrated EMG from the medial gastrocnemius increased for HC. After the expedition, red blood cell (from 423.4 plus or minus 15.4 to 498.0 plus or minus 24.510 super(4) mu l super(-1)), hemoglobin content (from 12.6 plus or minus 0.32 to 14.5 plus or minus 1.00g/dl) and 2,3-diphosphoglycerate (from 1.93 plus or minus 0.21 to 2.24 plus or minus 0.34 mu mol/ml) increased. The SpO sub(2) under HC increased from 69.2 plus or minus 9.6 to 77.2 plus or minus 10.0%. The maximum amplitude of sway with the eyes open decreased for HC. No difference in the sway path length and integrated EMGs was observed between NC and HC. These results suggest that acclimatization can improve the impaired postural stability on initial arrival at altitudes. However, it is still unclear how long acclimatization period is needed. Further studies are needed to reveal this point.