THE EFFECT OF GAS DENSITY ON THE WORK OF BREATHING IN MAN
Final rept. Jan 1964-Feb 1965
SCHOOL OF AEROSPACE MEDICINE BROOKS AFB TX
Pagination or Media Count:
The effect of gas density on the work of breathing was studied in 3 normal male subjects. Gas density was varied by decreasing the barometric pressure in an altitude chamber, as well as by varying the percentage of oxygen with nitrogen and helium. Three frequencies of breathing were selected at 8, 16, and 24 breaths per minute to cover the resting physiologic range, with tidal volume adjusted to allow an alveolar ventilation of 6 liters per minute. There appeared to be a slight decrease in the total work of breathing at the lower gas densities, owing to a decrease in the nonelastic work of breathing. The elastic work was not influenced by gas density but did decrease with increasing breathing frequency. The non-elastic work likewise was affected by frequency, decreasing at the lower breathing frequencies. The order of magnitude of these changes, however, would probably not be of any practical significance and thus would not be a factor in the preferential selection of a particular gas mixture - cabin pressure combination for a manned space vehicular environment.
- Anatomy and Physiology
- Stress Physiology