Distribution of hemoglobin and functional consequences of anemia in adult males at high altitude.

In order to assess better the normal hemoglobin (Hb) range among adult males at high altitude, a hematological survey was completed in La Paz, Bolivia (3700 m). Two statistical methodologies were utilized to identify the anemic and polycythemic contributions to the Hb distribution of normal healthy men (n = 526). The Hb of normal men has a Gaussian distribution with mean and SD of 18.8 +/- 1.4 g/dl. Cutoff levels of 15.8 and 22.0 g/dl Hb were selected to identify the anemic and polycythemic subpopulations. Iron status in this high altitude population is similar to that of low altitude populations, and iron deficiency is the cause of most anemia found. An exercise test on a subsample of 56 men was utilized to validate the anemia cutoff level. Anemics as identified by the 15.8 g/dl Hb level showed a significant reduction in aerobic capacity as measured by PWC150 and estimated VO2max.