Work Performance at Altitude After Adaptation in Man and Dog

Abstract

The work performance of 3 human subjects was initially recorded by a standard treadmill test at 760 feet. These tests were repeated at 14,900 feet after 2.5 months adaptation to this altitude, and again 2 weeks after return to the initial low altitude of 760 feet. A similar treadmill test was used to measure the work performance of 4 carefully selected and trained dogs at 760 feet, before and during residence at a simulated altitude of 19,000 feet in an altitude chamber, and after they had been re-compressed to 760 feet. A breathing mixture of 10% O2 and 90% N was used during the simulated high altitude work performance test. Ventilation, O2 consumption and pulse rates were re-corded. There was a marked increase in ventilation and ventilatory equivalents for a given work load at altitude for all subjects without a corresponding increase in the heart rate. O2 consumption was quite constant for similar work loads in all tests. Characteristic rises in hemoglobin, hematocrit, and red blood cell count were noted in all subjects. Lactic pyruvic acid ratios were much lower at altitude in the human subjects.