The effects of carbon monoxide on three types of performance at simulated altitudes of 10,000 and 15,000 feet.

Abstract

Measurements of the critical flicker frequency threshold, body sway, and the red visual field were made on subjects before, during and after low pressure chamber runs. Twenty subjects with 12-22% blood COHb took part in runs at 15,500 ft., and 6 subjects with 5-10% COHb were tested at 10,000 ft. Control runs were made at the same altitudes with the same subjects. There was a significant impairment of performance at altitude, both under conditions of anoxia alone and anoxia after exposure to CO. However, no significant difference was found between the mean scores of tests during anoxia and those during anoxia after CO was breathed. Incipient collapses occurred: 3 at 15,500 ft. without CO; 4 at 15,500 with CO, and one at 10,000 with CO. It is thought that the additional burden imposed by the stated increments of COHb, under conditions of light .activity, is masked by compensatory activities evoked by the moderate anoxia associated with these altitudes.