title: Effect of prolonged exercise on arterial oxygen saturation in athletes susceptible to exercise-induced hypoxemia.
abstract: This study examined the effect of prolonged endurance exercise on the development of exercise-induced hypoxemia (EIH) in athletes who had previously displayed EIH during an incremental maximal exercise test. Five male and three female endurance-trained athletes participated. Susceptibility to EIH was confirmed through a maximal incremental exercise test and defined as a reduction in the saturation of arterial oxygen (SpO(2)) of >/=4% from rest. Sixty minutes of running was conducted, on a separate day, at an oxygen consumption corresponding to 95% of ventilatory threshold. Immediately following the 60 min exercise bout, athletes commenced a time trial to exhaustion at 95% maximal oxygen consumption (VO(2max)). The reduction in SpO(2) was significantly greater during the maximal incremental test, than during the 60 min, or time trial to exhaustion (-8.8+/-1.4%, -3.3+/-1.1%, and -4.1+/-2.3%, P<0.05, respectively). The degree of desaturation during the 60 min was significantly related to the relative intensity of exercise at 95% ventilatory threshold (adjusted r(2)=0.54, P=0.02). In conclusion, athletes who did not exercise at greater than 73% VO(2max) during 60 min of endurance exercise did not display EIH, despite being previously susceptible during an incremental maximal test.
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Qld, Australia. i.stewart@qut.edu.au
authors.forename: I B
authors.initials: IB
authors.lastname: Stewart
authors.forename: R L
authors.initials: RL
authors.lastname: Pickering
mesh_terms: D000293:Adolescent; D000328:Adult; D001158:Arteries / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000209:etiology*; D008297:Male; D010100:Oxygen / Q000032:analysis*; D010101:Oxygen Consumption / Q000502:physiology*; D005082:Physical Exertion; D011793:Queensland
chemical_list: D010100:Oxygen