Arterial O2 Desaturation During Supine Exercise in Highly Trained Cyclists
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Performance of intense dynamic exercise in highly trained athletes may be associated with a drop in arterial O2 saturation (%SaO2), also called exercise-induced hypoxemia (EIH) (4, 9). The causes for this gas exchange imperfection are unclear, but ventilation-perfusion mismatch is considered an important factor (5, 6). Blood flow distribution in the lung is greatly influenced by body position, and ventilation-perfusion distribution, reportedly, is more homogenous in the supine (Sup) than in the upright (Up) position (1). In order to examine the influence of body posture on %SaO2 in exercise, we exercised a group of elite road cyclists progressively to maximum in Sup and Up, the hypothesis being that an expected desaturation in upright cycling would disappear or be reduced during supine work as a result of attenuation of uneven ventilation-perfusion distribution.
KeywordsTrained Athlete Ventilatory Capacity Supine Exercise Upright Exercise Lower Work Intensity
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