Preserved peak exercise capacity in Andean highlanders with excessive erythrocytosis both before and after isovolumic hemodilution
Cecilia Anza‐Ramirez, Wanjun Gu, José Luis Macarlupú, Rómulo Figueroa‐Mujíca, Gustavo Vizcardo‐Galindo, Erica C. Heinrich, Michael S. Tift, Harrieth Wagner, Peter D. Wagner, Tatum S. Simonson, Francisco C. Villafuerte
Abstract
Male Andean highlanders with and without excessive erythrocytosis (EE) have similar peak V̇o 2 at 4,340 m, with higher arterial [O 2 ] in EE and lower cardiac output (Q̇t), thus maintaining similar O 2 delivery. Peak V̇o 2 in participants with EE was unaffected by isovolumic hemodilution (hematocrit reduced from 67% to 53%), with lower O 2 delivery balanced by slightly increased Q̇t and greater O 2 extraction. Differences in lung and muscle diffusing capacity, and not hematocrit variation, accounted for essentially all interindividual variance in peak V̇o 2 .