The effect of exercise on exhaled nitric oxide depends on allergic rhinoconjunctivitis in children

Abstract

Objective: Fractional exhaled nitric oxide (FE_NO) and exercise testing are widely used for the evaluation of pediatric asthma. The evidence relating to the effects of strenuous exercise on FE_NO in children is conflicting. Little information is available on the association between exercise and FE_NO in relation to allergic rhinoconjunctivitis (AR). We aimed to investigate the effects of AR on children's FE_NO in response to a standardized treadmill exercise test. Methods: A total of 124 children with current asthma and 124 non-asthmatic children aged 8–16 years were studied. FE_NO was measured at baseline, at 1 and 30 min after an exercise challenge test using the single breath technique with EcoMedics Exhalyzer®. A structured parental interview, spirometry, serum allergen-specific IgE and skin prick tests were performed. Results: Baseline FE_NO was higher in both asthmatics and non-asthmatics with AR than without AR (both p < 0.001). The FE_NO time trend was dependent on AR (p = 0.039), irrespective of asthma (p = 0.876). In children with AR, FE_NO had declined at 1 min by a mean of 6.1 ppb with a 95% confidence level of 5.1–7.5 ppb; at 30 min, the reduction was 2.8 (2.5–3.3) ppb. In children without AR, at 1 min the decline in FE_NO was 2.7 (2.1–3.5) ppb and by 30 min post-exercise it was 1.6 (1.3–2.0) ppb. Conclusions: The impact of exercise on FE_NO was dependent on the allergic phenotype, regardless of asthma status. FE_NO decreased immediately after exercise, and did not return to baseline level within 30 min.

• Allergic rhinoconjunctivitis
• asthma
• exercise test
• FE_NO
• children

Acknowledgements

We thank Professor Tom Wilsgaard and PhD Tonje Braaten for statistical advice. We thank MD Sandy Goldbeck-Wood and Emeritus Professor Evert Nieboer for critically editing the article and MD Terje Tollåli for helpful discussions. We gratefully acknowledge the enthusiasm and cooperation of all participating children and parents.

Declaration of interest

The study was supported by grants from the Northern Norway Regional Health Authority, the Norwegian Respiratory Society and the Morten Jensens foundation. The authors declare no conflicts of interest, in terms of the ICMJE definition, in respect of the authorship and/or publication of this article.