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Updated: Jun 20, 2026

A Model to Simulate Clinically Relevant Hypoxia in Humans
Published on: December 22, 2016
Hydration and the physiological responses to acute normobaric hypoxia
Alan Richardson1, Peter Watt, Neil Maxwell
1University of Brighton, Chelsea School Reseasrch Centre, Eastbourne, United Kingdom. a.j.richardson@brighton.ac.uk
Objective:
The effect hydration status has on exposure to hypoxia is unclear. The purpose of the study was to identify how hydration status, above and below euhydrated levels, affects the physiological responses and onset of acute mountain sickness symptoms during acute normobaric hypoxia.
Methods:
Eight males completed intermittent walking tests under normobaric hypoxic conditions (FIo2 = 0.13) after controlled hyperhydration, hypohydration, and euhydration protocols. A range of physiological, psychological, and altitude illness markers were monitored throughout the 125-minute exposure.
Results:
Heart rate, core temperature, peripheral arterial oxygen saturation, urine osmolality, and mean self-reported Lake Louise Questionnaire acute mountain sickness scores were significantly different between euhydration, hypohydration, and hyperhydration, respectively, and closely correlated with environmental symptoms questionnaire, Lake Louise questionnaire, and headache scores (P < .05). Other measures of ventilation and lung function were also significantly different between hydration conditions (P < .05).
Conclusions:
Hydration state above and below euhydration has detrimental consequences on physiological strain and onset of acute mountain sickness symptoms when exposed to acute normobaric hypoxia.
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