title: Influences of exercise and endurance training on the oxygen dissociation curve of blood under in vivo and in vitro conditions.
abstract: In experiments with graded exercise of 15 men (6 untrained, 3 semitrained, 6 endurance-trained) the trained subjects showed a massive shift to the right of the in vivo O2 dissociation curve (ODC) of femoral venous blood. At a saturation of 20 to 25% (18 mkp/sec) Po2 was about 9 mm Hg higher for the trained than for the untrained group. The following factors play a role: 1. The 2,3-diphosphoglycerate [2,3-DPG] concentration was increased by 15 to 20% in the trained group which explains about 2 mm Hg of the diffenence in Po2-2. Exercise acidosis in the femoral venous blood depends to a large extent on CO2 in the trained, but on lactic acid in the untrained group. At low saturations the CO2-Bohr effect increases sharply thus having a greater importance in the trained subjects. This factor can explain about 2 mm Hg of the difference. However, influence of chloride and 2,3-DPG on the Bohr effect must be taken into consideration. 3. Since the large ODC-shift to the right of the trained group was not reproducible under in vitro conditions, it is suggested that a rapidly decaying unknown substance accounts for the remaining difference in Po2.
mesh_terms: D000136:Acid-Base Equilibrium; D000138:Acidosis; D000328:Adult; D002245:Carbon Dioxide / Q000097:blood; D004163:Diphosphoglyceric Acids / Q000097:blood; D004912:Erythrocytes / Q000032:analysis; D005268:Femoral Vein; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000097:blood; D008297:Male; D010313:Partial Pressure; D010806:Physical Education and Training; D005082:Physical Exertion
chemical_list: D004163:Diphosphoglyceric Acids; D006454:Hemoglobins; D007773:Lactates; D002245:Carbon Dioxide