Abstract des Autors

In the past decade, new facts were detected on improving oxygen transport, expecially during adaptation to extreme altitude. An increased hypoxic drive on ventilation makes it possible to transport the volume of oxygen necessary for a 120 W work performance into the alveoli even at 8800 m of altitude, however, with a tremendous hypocapnia as a consequence. The diffusion capacity of the lungs probably increases resulting from the rise in hemoglobin concentration. Hemodilution reduces maximal oxygen uptake in healthy subjects at high altitude. Influence of changes in acid-base status and 2,3-diphosphoglycerate on oxygen affinity cancel each other in arterial as well as in mixed venous blood up to extreme altitude. In the muscle, fiber diameter and mitochondrial volume decrease whereas the capillary network remains unaffected. The diffusion capacity of the muscle thus is increased. Performance inprovements at sea level following altitude training possibly result from an increased buffer capacity. Verf.-Referat