Effect of breathing O2 at one atmosphere on the response to cold in human subjects.

Abstract

Experiments were designed to verify the suggestion, from previous work, that breathing O2 decreased the O2 consumption of humans during exposure to cold. The results of 4 measurements on each of 10 subjects, dressed and at normal room temperature (25°C) showed no significant difference between breathing air and O2 (P = 0.6). During the next experiments the room temperature was about 10°C. Two determinations of the O2 consumption were made while the subject was covered with blankets and four more after the nude subject had been exposed to room temperature for 20 minutes. Movements of the suspended bed were recorded during shivering. An electromyograph record was also obtained. For analysis the results were grouped into successive pairs of observations for breathing air and O2. The average decrease in O2 consumption when breathing O2 was 19.7 cc/min/m2 which represented 30% of the mean increase in O2 consumption in the cold and was significantly different from zero (P < 0.001). Breathing O2 also resulted in a lower heart rate (3 beats/min.,P < 0.001), lower minute volume (13.8% of increase due to cold, P = 0.02), lower respiratory frequency (0.48 cpm, P = 0.08) and lower EMG (16.8 μv, P = 0.08). Tremor was not affected by O2 (P = 0.90). Submitted on December 18, 1957