title: High-altitude adaptation and maximum work performance.
abstract: 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.
mesh_terms: D000222:Adaptation, Physiological; D000531:Altitude; D000818:Animals; D001810:Blood Volume; D006400:Hematocrit; D008297:Male; D005082:Physical Exertion; D051381:Rats; D011919:Rats, Inbred Strains