Abstract des Autors

The aim of this study was to investigate the development of exercise-induced hypoxemia (EIH defined as an exercise decrease > 4 % in oxygen arterial saturation, i. e. SaO2 measured with a portable pulse oximeter) in twelve sportsmen and ten sportswomen (18.5 ± 0.5 years) who were non-elite and not initially engaged in endurance sport or training. They followed a high-intensity interval-training program to improve VO2max for eight weeks. The training running speeds were set at <140 % VO2max running speed up to 100 % 20-m maximal running speed. Pre- and post-training pulmonary gas exchanges and SaO2 were measured during an incremental running field-test. After the training period, men and women increased their VO2max (p<0.001) by 10.0 % and 7.8 %, respectively. Nine subjects (seven men and two women) developed EIH. This phenomenon appeared even in sportsmen with low VO2max from 45 ml/min/kg and seemed to be associated with inadequate hyperventilation induced by training: because only this hypoxemic group showed 1) a decrease in maximal ventilatory equivalent in O2 (VE/VO2, p<0.01) although maximal ventilation increased (p<0.01) with training, i. e. in EIH-subjects the ventilatory response increased less than the metabolic demand after the training program; 2) a significant relationship between SaO2 at maximal workload and the matched VE/VO2 (p<0.05, r=0.67) which strengthened a relative hypoventilation implication in EIH. In conclusion, in this field investigation the significant decrease in the minimum SaO2 inducing the development of EIH after high-intensity interval-training indicates that changes in training conditions could be accompanied in < 40 % non-endurance sportive subjects by alterations in the degree of arterial oxyhemoglobin desaturation developing during exercise. Verf.-Referat