The effect of moderate altitude on post-exercise blood lactate

Summary Post-exercise blood lactate levels were studied after a short exhaustive bicycle ride in 3 males at sea level control, at altitude (2300 m) and on return to sea level. The short exhaustive bicycle ride was performed at a work rate of 2730 kpm · min^–1 and ride times ranged from 55 to 105 sec. Compared to sea level controls, performance time of the tests at altitude were of similar intensity and duration. Although the changes were small, the oxygen uptakes during the ride and oxygen debts following the rides increased with each test. However, in comparison with sea level controls the blood lactate concentrations were reduced. The reduction on the average reached 44% after 4 days at altitude, and 51% after 22 days at altitude. This reduction in blood lactate concentration of the same subject at altitude as compared with his sea level values may indicate a decrease in the activity of the glycolytic pathway relative to the activity of the aerobic pathway. This appears to be a contradiction to what would be expected in the mild hypoxic conditions present at altitude.Work done while at the University of Michigan, Ann Arbor, Michigan.This study was supported in part by a grant from the Fitness and Amateur Sport Directorate, Ottawa, Canada.