L. Nelson, C. Brownell, K. Cook, E. Rhoads, K. Weigel, PL. Crosswhite

Gonzaga University, Spokane, WA

The pathophysiology of acute mountain sickness (AMS) is thought to be the result of abnormal water and sodium retention by the kidney, but the causal mechanisms are still largely unknown. Furthermore, there is limited research on AMS within an environmental chamber, which can control for confounding variables compared to field research with subjects exposed to the elements. PURPOSE: The purpose of this study was to investigate potassium (K+) as a potential treatment for mitigating symptoms caused by AMS. METHODS: Six subjects (4 female and 2 male) recruited from the Gonzaga University student population completed two experimental trials. Prior to each trial, subjects supplemented with K+, or a placebo, for three days. The experimental trials included two hours inside an environmental chamber, with twenty-minute walking and sitting intervals on a treadmill. Blood was collected before and after subjects entered the chamber. RESULTS: The K+ supplement was effective, causing a significant increase in plasma potassium levels (placebo trial = 5.9 ± 3.0 mmol/L and K+ trial = 7.6 ± 1.2 mmol/L, p=.04). A weak but positive correlation was observed between pre and post Na+ and K+ plasma levels (r=0.207, p=0.695). Furthermore, plasma Na+ levels decreased more when participants supplemented with K+ (t = 0.28, p = 0.40). Using a modified Lake Louise assessment, 1/5 subjects diagnosed as positive AMS during the placebo trial, while 3/5 subjects diagnosed as positive AMS during the K+ trial. CONCLUSION: While K+ supplementation did achieve increased natriuresis, hyperkalemia is also known to have a direct stimulatory effect on aldosterone, which triggers increased sodium reabsorption and may lead to increased water retention. Our results suggest it may be beneficial to avoid excess consumption of electrolytes, especially ones containing high levels of K+, before ascending to altitude. However, the direct effects of K+ in the mechanism of AMS remains unclear.

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