Prevalence of exercise-induced oxyhemoglobin desaturation and the effect of posture in healthy untrained young subjects

Exercise-induced hypoxemia is a common observation in endurance-trained athletes. The present study examined the kinetics of oxyhemoglobin saturation during upright (UP) maximal cycling exercise in 84 healthy, untrained subjects between 8 and 26 years old. The prevalence of oxyhemoglobin desaturation (DS: SaO$ sb2 $ 0.05). A subgroup of children (n = 6) repeated the maximal exercise protocol in the supine (SU) position. In NDS values of SaO$ sb2$ were not affected by posture (UP: 95.3 $ pm$ 2.3 vs SU: 94.1 $ pm$ 0.9) for similar VO$ sb{ rm 2max}$ (UP: 3.7 $ pm$ 0.36 vs SU: 3.43 $ pm$ 0.36) (p $>$ 0.05). These observations suggest that exercise-induced DS is independent of age or training status. Differences due to posture may be related to variations in ventilatory and/or pulmonary perfusion parameters