[Effect of maximum physical exertion on the oxygen transport system of the blood]

Ventilation, gas exchange, gas composition and pH of venous blood, as well as oxyhemoglobin dissociation curves were investigated during exercise tests of 9 healthy volunteers, aged 19-31. During maximal exercises the dissociation curve shifted to the right. The shift was associated with the extraerythrocyte factor, i.e. the Bohr effect due to metabolic acidosis in muscles. The shift which indicates a lower hemoglobin affinity for oxygen and a higher oxygen release by blood is of adaptive importance: during exercises oxygen supply to tissues increases. This shift is also evidenced by an increase of venous pO2 during muscle work.