Self-reported respiratory symptoms are poor indicators of exercise-induced bronchoconstriction in early-career athletes

Respiratory symptoms relate poorly to exercise-induced bronchoconstriction (EIB) in elite athletes. This relation is less well studied in early-career athletes. Forced oscillometry (FOT) is regarded to be a more sensitive method to detect airway obstruction and may better relate to symptoms than spirometry. We studied self-reported respiratory symptoms in relation to changes after exercise challenge in lung function, assessed by respiratory resistance at 5 Hz (R5) and forced expiratory volume in one second (FEV1), in two groups of adolescents: athletes from a sports high school (N=98) and from the general population (N=150). ∆R5 and ∆FEV1 were defined using the largest change of R5 and FEV1 up to 30 minutes after exercise. The association between respiratory symptoms and ∆R5 and ∆FEV1 were analyzed by logistic regression. EIB defined as ∆FEV1 ≤-10% was found in 22% among the athletes and 32% in the general population. No significant associations were found among the athletes between symptoms and ∆R5 or ∆FEV1. However, in the general population wheeze was associated (odds ratio (95% confidence interval)) with both ∆R5 (1.02 (1.00-1.03)) and ∆FEV1 (0.95 (0.91-0.99)). Exercise-induced dyspnea and waking up with chest tightness related to ∆FEV1 (0.92 (0.88-0.98) and 0.95 (0.91-0.99), respectively) while waking up with dyspnea related to ∆R5 (1.02 (1.00-1.04)). In early career athletes, self-reported respiratory symptoms have limited predictive value for EIB. Although relations could be found among adolescents from the general population, the association between respiratory symptoms and EIB is weak. This confirms the need for standardized testing when investigating EIB.