Impaired postural control in healthy men at moderate altitude (1630 m and 2590 m): data from a randomized trial.
OBJECTIVE
Intact postural control is essential for safe performance of mountain sports, operation of machinery at altitude, and for piloting airplanes. We tested whether exposure to hypobaric hypoxia at moderate altitude impairs the static postural control of healthy subjects.


METHODS
In 51 healthy men, median age 24 y (quartiles 20;28), static control was evaluated on a balance platform in Zurich, 490 m, and during a 4-day sojourn in Swiss mountain villages at 1630 m and 2590 m, 2 days each. The order of altitude exposure was randomized. Total center of pressure path length (COPL) and sway amplitude measured in two directions by a balance platform, and pulse oximetry were recorded. Data were compared between altitudes.


RESULTS
Median (quartiles) COPL during standing on both legs with eyes open at 490 m and in the evenings on the first and second days at 1630 and 2590 m, respectively were: 50 (45;57), 55 (48;62), 56 (49;61), 53 (47;59), 54 (48;60) cm, P<0.001 ANOVA. Corresponding arterial oxygen saturation was 97% (96;97), 95% (94;96), 95%(94;96), 92%(90;93), 93%(91;93), P<0.001. Anterior-posterior sway amplitudes were larger at 1630 and 2590 m compared to 490 m, P<0.001. Multiple logistic regression analysis confirmed that higher altitudes (1630 and 2590m) were independently associated with increased COPL when controlled for the order of altitude exposure and age (P=0.001).


CONCLUSIONS
Exposure to 1630 and 2590m was associated with impaired static postural control even when visual references were available.


BACKGROUND
ClinicalTrials.gov NCT01130948.
Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland; Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.
Katrin
K
Stadelmann
Pulmonary Division, University Hospital Zurich, Zurich, Switzerland.
Tsogyal D
TD
Latshang
Pulmonary Division, University Hospital Zurich, Zurich, Switzerland.
Christian M
CM
Lo Cascio
Department of Physiotherapy, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Australia.
Ross A
RA
Clark
Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; University Children's Hospital Zurich, Zurich, Switzerland.
Reto
R
Huber
Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; Pulmonary Division, University Hospital Zurich, Zurich, Switzerland.
Malcolm
M
Kohler
Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland; Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.
Peter
P
Achermann
Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; Pulmonary Division, University Hospital Zurich, Zurich, Switzerland.
Konrad E
KE
Bloch
D000328:Adult; D000368:Aged; D000531:Altitude; D001274:Atmospheric Pressure; D064368:Healthy Volunteers; D006801:Humans; D000860:Hypoxia; D008297:Male; D008875:Middle Aged; D010100:Oxygen; D010101:Oxygen Consumption; D011187:Posture; D055815:Young Adult
D010100:Oxygen