Exercise-induced arterial hypoxemia in gas exchange between alveoli and blood vessels (EIAH):
EIAH significantly contributes to the onset of fatigue in the arms and legs and can account for up to 15% of the loss in VO₂max.
In 30 to 70% of endurance athletes, we observe a drop in oxygen concentration during intense exercise. There is a decrease in hemoglobin saturation by 4 to 12% and in arterial oxygen pressure by 10 to 30 mmHg. In these athletes, we see a marked difference in oxygen concentration between the alveoli and the blood vessels, along with a limited hyperventilation response.
Factors contributing to this decrease in oxygen include the ratio between alveolar ventilation and the perfusion of blood vessels at the level of the alveoli. Proper ventilation of the alveoli and adequate perfusion of the surrounding blood vessels are essential for ensuring sufficient oxygen transfer into the bloodstream.
Studies show that this drop in blood oxygen concentration negatively affects muscle fatigue and exercise capacity.