Physical Fitness and Human Tolerance to Acute Exposure to Life at High Altitude. Effect on Hematocrit and Hemoglobin Values of Variations in the State of Physical Activity, Physical Condition and Altitude

摘要

Attention was focused on three variables: (1) The role of exercise in raising the hematocrit; (2) the role of physical fitness in preserving a degree of homeostasis close to an hematocrit level of 40 which is the viscosity and cell concentration for optimal 'oxygen flow' to the tissue; and (3) the role of changing altitudes as an independent variable which change is associated with a rise in hematocrit and hemoglobin both at rest and during exercise and more so in the sedentary than in the fit subject. The data suggest that the peripheral venous blood hematocrit and hemoglobin levels are lower in athletes than they are in sedentary or fit subjects. Exposing athletes to high altitude apparently does not raise these lower hematocrit and hemoglobin levels as much as this exposure does in healthy normal subjects. This phenomenon can be interpreted to be evidence for a physiological cross-adaptation between high degrees of physical fitness and speed of acclimatization to high altitude. (Author)