Evidence of exercise-induced O2 arterial desaturation in non-elite sportsmen and sportswomen following high-intensity interval-training

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. SaO(2) 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 VO(2)max for eight weeks. The training running speeds were set at similar to140% VO(2)max running speed up to 100% 20-m maximal running speed. Pre- and post-training pulmonary gas exchanges and SaO(2) were measured during an incremental running field-test. After the training period, men and women increased their VO(2)max (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 VO(2)max from 45 ml x min(-1) x kg(-1) and seemed to be associated with inade-quate hyperventilation induced by training: because only this hypoxemic group showed 1) a decrease in maximal ventilatory equivalent in 02 (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 SaO(2) 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 SaO(2) inducing the development of EIH after high-intensity interval-training indicates that changes in training conditions could be accompanied in similar to40% non-endurance sportive subjects by alterations in the degree of arterial oxyhemoglobin desaturation developing during exercise.