Effects of prior hypoxia exposure on visual target detection during later more severe hypoxia

Three groups of 15 subjects each were exposed to 3 different combinations of intermediate (staging) altitudes and exposure times, and were then tested for visual target detection capability at a final altitude of 4300 m. All groups with staging exposure performed better at altitude and had fewer symptoms of acute mountain sickness than a fourth group which went directly to 4300 m altitude from sea level. The data showed that task factors of both viewing distance and degree of peripheral placement of the target significantly influenced detection time within all groups regardless of variations in exposure to altitude.