PERFORMANCE AS RELATED TO COMPOSITION OF ALVEOLAR AIR

Abstract

Per-formance, (contrast discrimination test and hand steadiness test) and heart rates of human subjects were measured during 1/2 hr. exposures to various alveolar CO2 and O2 ten-sions. The results are plotted on pCO2-PO2 coordinates, and regions of normal performance and of various types of impaired performance are delineated. An analysis of performance impairment in terms of anoxic and acapnic components indicates that acapnia and anoxia are additive rather than antagonistic in their effects on performance, and that there exists at each altitude an optimum alveolar gas composition for best performance. This optimum may be different for different types of performance, however. Performance impairment in most individuals breathing naturally at air-breathing altitudes is essentially a matter of anoxia alone. Heart rate is increased by anoxia but is not consistently affected by acapnia.