Oxygenation during rapid ascent and residence at 3,800 m. Data were obtained via arterial blood gas/electrolyte measures at 1,045 m (day 0), prior to ascent, and at 3,800 m on days 2 (within 24 h of arrival by rapid ascent) and 9. A: , pressure of arterial oxygen. B: , arterial oxygen saturation. C: [Hb], hemoglobin concentration D: , arterial oxygen content. *Different than day 0. †Different than previous day. Presented as means ± SD. n = 16.