Abstract
ObjectivesIntact 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.MethodsIn 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.ResultsMedian (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).ConclusionsExposure to 1630 and 2590m was associated with impaired static postural control even when visual references were available.Trial RegistrationClinicalTrials.gov NCT01130948.
Highlights
Control of posture is essential for the safe performance of many activities of daily life, and in particular for sports, operating cars, machinery and for piloting airplanes
Total center of pressure path length (COPL) and sway amplitude measured in two directions by a balance platform, and pulse oximetry were recorded
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)
Summary
Control of posture is essential for the safe performance of many activities of daily life, and in particular for sports, operating cars, machinery and for piloting airplanes. Impairments in postural stability during short exposures of a few hours to simulated altitudes between 1500 m and 5500 m have been reported [7,8,9]. It remains unclear whether such impairments persist or even aggravate during a prolonged stay at altitude, and to which extent they are altitude-dependent [7,9,10]. Whether similar impairments in postural control occur and persist during a prolonged stay even at moderate altitudes of 1600 to 2600 m remains unknown. Applying a randomized cross-over study design we tested the hypothesis that static control was impaired in an altitude dependent manner at Davos Jakobshorn (2590 m) compared to Davos Wolfgang (1630 m) and Zurich (490 m), respectively
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