AJP - Regulatory, Integrative and Comparative Physiology, Vol 246, Issue 4 619-R623, Copyright © 1984 by American Physiological Society
High-altitude adaptation and maximum work performance
E. S. Johnson and C. A. Finch
The treadmill work performance of rats at sea level with normal or elevated
hematocrits was compared with that of rats conditioned in a hypobaric
chamber at 450 Torr for 3 wk with similar hematocrit adjustments. A mean
increase in hematocrit to 62 significantly improved the work performance of
rats at sea level and at ambient O2 tensions of 100, 75, and 35 Torr. By
contrast, rats conditioned in a hypobaric chamber with mean hematocrits of
40 and 58 performed similarly at all O2 tensions compared with sea-level
rats with hematocrits of 43. Thus, although an increase in O2-carrying
capacity of the blood of sea-level animals increased work capacity,
altitude adaptation did not appear to result in any positive effect on work
capacity, and indeed, seemed to interfere with the beneficial effect of
polycythemia on maximum work performance.
