Developing pilot methodologies for monitoring hydration status in acute mountainous environments

Unaddressed dehydration is a serious medical problem in individuals facing extreme environmental, tactical or physical challenges, such as mountaineers, cold endurance athletes and military personnel. Dehydration directly impairs aerobic capacity, cognitive function, concentration, and may increase the risk of cold injury, acute mountain sickness (AMS), and in severe cases lead to death, yet individuals have limited ability to determine dehydration in acute, remote environments during mountaineering expeditions. The goal of this pilot study was to determine if field-capable hydration assessments correlated with gold-standard dehydration measurements in Cascadian mountaineers. In this pilot study, we employed in-field hydration assessment methods (urine color analysis, urine output, and urine specific gravity strips) and as well as classical, goal-standard measurements of hydration (urine osmolality) with longitudinal urine sampling in three mountaineers over the course of a climb (total n=21 unique data points). We also employed daily food/fluid intake questionnaires and health symptom surveys. Preliminary data suggests that hydration status in mountainous environments may correlate with total urine output and qualitative dehydration surveys, suggesting a potential method of populations accessing their hydration status in the field. The development of robust, in-field health data and urine sampling protocols that were obtained from this research lays crucial groundwork for the development of future longitudinal studies with aims of obtaining human data in extreme environments to develop performance, health and safety recommendations for populations in acute mountainous environments. Research reported in this publication was supported by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under grant number P20GM103395. The content is solely the responsibility of the authors and does not necessarily reflect the official views of the NIH. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.