Effects of normobaric hypoxia on equilibrium and sensory organization
Poster session at 62nd Annual Meeting of the American College of Sports Medicine (ACSM)
San Diego, CA
Dizziness or lightheadedness is a common symptom following rapid ascent to high altitude, which could result in diminished equilibrium. However, the effect of hypoxia on balance has not been well studied. PURPOSE: Compare the effects of varying levels of nomobaric hypoxia on equilibrium and sensory organization before and after exercise. METHODS: Following a familiarization trial, 12 males (27.3 ± 7.1 y) completed 3 sessions on a NeuroCom SMART Balance Master. This device provided an assessment of the sensory and motor control of balance on either a stable or unstable surface and in a stable or dynamic visual environment. A composite equilibrium score was determined. Additionally, information on somatosensory, visual, and vestibular responses was obtained. The 3 sessions were performed under 3 altitude conditions: a sham trial at the ambient altitude of 1400 m (LOW) and simulated altitudes of 3000 m (MID) and 5000 m (HIGH) created by a hypoxic generator. The order of the 3 altitude sessions was randomized. Each session consisted of 20 min of rest followed by the NeuroCom test, then 10 min of exercise (5 min walking at 3 mph and 5 min running at 6 mph) followed by a second NeuroCom test, all while connected to the hypoxic generator. Mean differences were identified with a two-way (pre/post exercise and altitude condition), repeated-measures ANOVA. RESULTS: The composite equilibrium score was significantly lower (p < 0.001) during the HIGH condition (73.4 ± 12.0) compared to the LOW (80.8 ± 7.0) and MID (84.1 ± 5.0) altitudes. Exercise had no additional influence on balance as the pre-exercise and post-exercise scores were not different (p = 0.91). The inability to ignore inaccurate visual cues in a situation of visual conflict was the most common error in the sensory analysis during the HIGH trials. CONCLUSIONS: Moderate hypoxia does not affect balance, but severe hypoxia significantly reduces equilibrium. Furthermore, it appears that the alterations in equilibrium are primarily from impairments in visual function.
Wagner D, Davis J, Saunders S, & Robertson B. (2015, May). Effects of normobaric hypoxia on equilibrium and sensory organization. Poster session at 62nd Annual Meeting of the American College of Sports Medicine (ACSM), San Diego, CA.