Epidemiology of Exercise-Induced Hypoxemia in Athletes and the Role of Expiratory Flow Limitation

摘要

Exercise-induced arterial hypoxemia (EIAH) is a recognized phenomenon in healthy subjects, although its epidemiology and mechanisms remain incompletely understood. In this study, we assessed the prevalence rates of EIAH among various populations and further explored whether expiratory flow limitation plays a role in its causation. Eighty-two subjects underwent incremental exercise protocols to maximum volitional fatigue while being monitored using forehead pulse oximetry. Pre- and post-exercise spirometric tests were employed to detect evidence of airway hyper-responsiveness and expiratory flow limitation. Results were stratified by severity of oxygen desaturation, gender, age, training, fitness level, and mode of exercise, and statistically compared to determine EIAH prevalence and characteristics of the desaturating populations. The prevalence of EIAH in our study population was 35.4% (37.1% for males and 30% for females), which was significantly lower than that reported previously. We additionally observed a higher prevalence of EIAH in moderately fit individuals than previously documented (32.7%) and lower prevalence in the least trained subjects (36.8% vs. 12.5%). Younger subjects displayed a trend towards greater development of EIAH. Spirometric analysis revealed no statistically significant differences in lung volumes and flow rates between individuals with normal saturation and those who displayed desaturation. Our documented prevalence of EIAH is significantly lower, but more common in less fit and younger individuals, compared to previously published findings. Moreover, our results do not support the theory that expiratory flow limitation is a major contributory mechanism in the development of EIAH.