THE EFFECT OF OXYGEN, ALTITUDE AND EXERCISE ON BREATH-HOLDING TIME

Abstract

1581 detns. of breath-holding time were made on 80 soldier volunteers. Randomization of control and exptl. measurements rendered the method reproducible and consistent. The hold appeared to depend primarily upon the O2 content of the lungs as demonstrated by various O2-air mixtures at ground level and at altitudes (decompression chamber) up to 38,000 ft. Hyperventilation increased the hold to a lesser extent and the 2 factors, O2 and CO2, appeared to act together. The hold was decreased progressively by increasing grades of exercise given over a standard period. The Valsalva maneuver which is a fundamental part of breath-holding appeared to increase the O2 saturation of the blood (measured with the Millikan Oximeter). At the end of the hold, the O2 saturation decreased sharply for a few secs. before the return to normal; saturation is about 30 secs. The general utility of the breath-holding maneuvers as a method for the study of respiratory physiology in man is discussed.