To examine evidence of exercise-induced bronchoconstriction (EIB) defined as ≥ 10% reduction in forced expiratory volume in one second (FEV ) and exercise-induced arterial hypoxemia (EIAH) defined as ≥ 4% reduction in oxygen saturation (SpO ) from before to after participation in the Norseman Xtreme Triathlon. Secondarily, to assess if changes in FEV and SpO , are related to respiratory symptoms, training volume and race time.
In this quasi-experimental non-controlled study, we included 63 triathletes (50♂/13♀) aged 40.3 (±9.0) years (mean ±SD). Fifty-seven (46♂/11♀) measured lung function and 54 (44♂/10♀) measured SpO before the race, 8-10 minutes after the race (post-test 1) and the day after the race (post-test 2). Respiratory symptoms and training volume were recorded with modified AQUA questionnaire. ANOVA for repeated measures was used to detect differences in lung function and SpO . Statistical significance was accepted at 0.05 level.
Twenty-six participants (46%) presented with EIB at post-test 1 and 16 (28%) at post-test 2. Lung function variables were significantly reduced from baseline to post-test 1 and 2. Thirty-five participants (65%) showed evidence of mild to moderate EIAH. No significant correlations were observed except a weak correlation between maximal reduction in FEV and respiratory symptoms (r=0.35, p=0.016).
Our results demonstrated that 46% of the participants presented with EIB and 65% showed evidence of EIAH after the Norseman Xtreme Triathlon. Changes in FEV and SpO were not correlated to weekly training hours or race time. We observed a weak correlation between maximal reduction in FEV and respiratory symptoms.

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