““Typical sympathoadrenal response to both acute and chronic high altitude exposure. During initial exposure, epinephrine levels increase dramatically as a direct result of hypoxia on stimulating adrenal medullary activity. As oxygen content improves over time with acclimatization, this stimulus is lessened and epinephrine levels return toward sea level values. Sympathetic nerve activity, however, increases steadily over time at altitude as indicated by both arterial and urinary norepinephrine levels. There is a transient increase in cortisol levels with initial exposure to altitude””
