Postexercise Airway Responses by Spirometry and Oscillometry in Nonathlete and Athlete Adolescents

Background Exercise‐induced bronchoconstriction (EIB) is common among adolescents and athletes. While typically assessed with spirometry, oscillometry may offer complementary insights. This cross‐sectional study examined how fractional exhaled nitric oxide (FeNO) and symptoms relate to postexercise airway responses assessed via spirometry and oscillometry, and whether these associations differ between nonathletes and athletes. Methods Subsamples from two adolescent cohorts ( N = 241; 143 nonathletes, 98 athletes) completed questionnaires, FeNO measurements, and an EIB test using spirometry, by change in forced expiratory volume in 1 s (∆FEV 1 ), and oscillometry, by change in resistance and reactance at 5 Hz (∆R 5 , ∆X 5 ). Correlations were assessed using Spearman's rank; logistic regression evaluated associations between elevated FeNO and EIB; linear regression explored links between symptoms and postexercise airway responses. Results EIB was detected in 70 participants via spirometry (∆FEV 1 ≤ −10%), 81 via oscillometry (∆R 5 ≥ 25%), and 37 by both. Among nonathletes, FeNO was weakly correlated with ∆FEV 1 ( r s = −0.17, p = 0.04), ∆R 5 (0.35, p < 0.001), and ∆X 5 (−0.25, p = 0.005). Elevated FeNO (> 20 parts per billion) was associated with EIB by ∆FEV 1 (aOR 2.54, 95% CI: 1.05–6.12) and ∆R 5 (aOR 3.05, 95% CI: 1.18–7.9). Respiratory symptoms also related to postexercise airway responses in nonathletes. In contrast, no such associations were observed in athletes. Conclusion In nonathletes, elevated FeNO and symptoms can indicate who needs EIB testing. These indicators were less predictive in athletes, emphasizing the value of objective assessment. Oscillometry was complementary to spirometry to assess EIB and a combination of methods might be more informative.