Relationships between kidney function and acute mountain sickness symptoms in healthy human adults.

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Upon rapid ascent to high altitude, increases in breathing can induce respiratory alkalosis - an increase in blood pH. Rapid ascent is known to induce alveolar hyperventilation, where one exhales more than one inhales, increasing the ratio of expelled CO2 to O2 intake. This reduction of CO2 in the blood creates a proportional surplus of bicarbonate ions, and shifts plasma pH to more alkaline levels. In order to restore blood acid-base balance, kidneys must compensate to excrete surplus bicarbonate ions via the urine. There is evidence of correlation between urine acidity - or lack of bicarbonate clearance - and AMS symptom severity. Furthermore, Acetezolamide, a drug known to improve kidney function at high altitude, is effective at alleviating AMS. Increased blood pH is known to impair cerebral auto-regulation, increase cerebral blood flow, and degrade the blood-brain-barrier. Given the symptoms of AMS, such as dizziness, headaches, nausea, and fatigue/lassitude, and its risks, such as high-altitude cerebral oedema (brain swelling), these changes in cerebral vasculature are a logically assumed source. All this considered, it has been suggested that interpersonal differences in AMS susceptibility arise from differences in kidney function. This study aims to prove the hypothesis that kidney function, cerebral auto-regulation, and AMS symptom severity are correlated phenomena. We also hope to produce a means of extrapolating AMS risk from measures of kidney function. This will allow future identification of at-risk individuals, and even indicate an avenue of inquiry into the management of AMS. In the advent of advanced transportation, and in the face of severe medical risks and even fatality from untreated AMS, this is pertinent. The study may also provide general information on cardiovascular function and cerebral auto-regulation dynamics within whole-body integrated physiology.