Exhaled nitric oxide decreases during exercise in non‐asthmatic children

• Published in: The Clinical Respiratory Journal
• Main Authors: Evjenth, Bjørg, Hansen, Tonje E., Holt, Jan
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2012
• Subjects: Nordland
• Online Access: http://dx.doi.org/10.1111/j.1752-699x.2012.00292.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1752-699X.2012.00292.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1752-699X.2012.00292.x

Abstract Introduction: Exhaled nitric oxide (FE NO ) measurements are recommended to be performed before spirometry and exercise challenge tests because forced breathing might influence FE NO values. Information on the effect of exercise on FE NO is lacking in non‐asthmatic children. Aim: To investigate the effect on FE NO of a standardized exercise challenge test on a treadmill in non‐asthmatic children with and without allergic rhinoconjunctivitis (AR) symptoms. Methods: From the case‐control study ‘Asthma and allergy among school children in Nordland’, 330 non‐asthmatic pupils age 8–16 years were enrolled. FE NO was measured at baseline and at 1 min and 30 min after exercise challenge test by the single breath technique with EcoMedics Exhalazer® (Eco Physics, Duernten, Switzerland). Results: Pair‐wise comparison of FE NO from baseline demonstrated a highly significant reduction in FE NO post‐exercise for all children at 1 min (27.4%) and at 30 min (16.1%) ( P < 0.001). The AR group had a significantly higher decline in FE NO value at 1 min post‐exercise compared to the non‐AR group, 4.2 parts per billion (ppb) vs 2.6 ppb ( P < 0.001). Decline in FE NO immediately post‐exercise was more significant if baseline FE NO was ≥ 20 ppb; mean reduction 9.9 (95% CI: 8.7–11.4) ppb. Conclusion: FE NO is reduced by 27.4% immediately after a standardized treadmill exercise test in non‐asthmatic children. Pupils reporting AR symptoms demonstrate a larger decline in FE NO value at 1 min post‐exercise compared to pupils without AR symptoms. These findings confirm that children should refrain from physical activity before FE NO measurement. Please cite this paper as: Evjenth B, Hansen TE and Holt J. Exhaled nitric oxide decreases during exercise in non‐asthmatic children. Clin Respir J 2013; 7: 121–127.