Pulmonary Diffusing Capacity Limiting Human Performance at Altitude

In 6 internationally successful endurance athletes measurements of oxygen uptake, and pulmonary diffusion capacity at maximal bicycle exercise were performed at sea level and after 3 weeks stay at 2250 m altitude (Mexico City). Maximal oxygen uptake was 10–17 % lower at altitude and this reduction was related to the ratio at sea level between D LCO /max Vo 2 , The findings demonstrated that there is a physiological basis not only for a more marked reduction of max Vo 2 in welltrained groups at altitude but also for the observed large differences in performance at altitude between athletes of equal capability at sea level.