In order to compare the work efficiency in hypoxia with that in normal environment, given work was loaded to five healthy male subjects in a decompression chamber. Hyoxia was induced by decompression to a simulated altitude of 4, 000 meter, where the subjects walked on a treadmill with a slope of 5% at a speed of 80 m/min for 10 minutes. Oxygen consumption, expiratory volume, R. Q., respiratory rate, heart rate, oxygen pulse, and oxygen removal were measured before, during and after the work. Blood samples were taken to determine lactate value before and after the work. The results obtained and the conclusion are as follows ;
1) Vo
2 at rest in the hypoxia was slightly less than that of the control, while the total oxygen consumed by the work was more in the hypoxia than the control value.
2) Making correction for anaerobic mechanism, effect of respiratory and circulatory acceleration, and decreased air density on oxygen consumption revieled that the true work efficiency in hypoxia was completely same as in the controle.
3) Respiratory quotient dropped in the early stage of the work, thereafter increased in the control, while it increased on work without initial drop in the hypoxia. Total extra CO
2 eliminated by the work was significantly more than the control value.
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