Exhaled nitric oxide decreases during exercise in non-asthmatic children

Authors

  • Bjørg Evjenth,

    Corresponding author
    1. Department of Pediatrics, Division of Pediatrics, Obstetrics and Women's Health, Nordland Hospital, Bodø, Norway
      Bjørg Evjenth, MD, Department of Pediatrics, Nordland Hospital, Post box 1480, 8092 Bodø, Norway. Tel: +47 75 53 40 00, Fax: +47 75 53 40 13, email: bjorg.evjenth@gmail.com
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  • Tonje E. Hansen,

    1. Department of Pediatrics, Division of Pediatrics, Obstetrics and Women's Health, Nordland Hospital, Bodø, Norway
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  • Jan Holt

    1. Department of Pediatrics, Division of Pediatrics, Obstetrics and Women's Health, Nordland Hospital, Bodø, Norway
    2. Institute of Clinical Medicine, University of Tromsø. Tromsø, Norway
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  • Authorship Bjørg Evjenth: Designed the study, collected data, analysed data, wrote the paper. Tonje E. Hansen: Collected data, wrote the paper. Jan Holt: Designed the study, wrote the paper.

  • Ethics The study was conducted after approval by the Regional Committee for medical and health professional research ethics and was performed in accordance with the ethical standards of the 2000 Declaration of Helsinki. Written informed consent was obtained from all children and their parents prior to their inclusion in the study.

  • Conflict of interest The authors have stated explicitly that there are no conflicts of interest in connection with this article.

  • Financial support The study was supported by grants from the Northern Norway Regional Health Authority, the Norwegian Respiratory Society and Morten Jensens foundation.

Bjørg Evjenth, MD, Department of Pediatrics, Nordland Hospital, Post box 1480, 8092 Bodø, Norway. Tel: +47 75 53 40 00, Fax: +47 75 53 40 13, email: bjorg.evjenth@gmail.com

Abstract

Introduction:  Exhaled nitric oxide (FENO) measurements are recommended to be performed before spirometry and exercise challenge tests because forced breathing might influence FENO values. Information on the effect of exercise on FENO is lacking in non-asthmatic children.

Aim:  To investigate the effect on FENO 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. FENO 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 FENO from baseline demonstrated a highly significant reduction in FENO 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 FENO 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 FENO immediately post-exercise was more significant if baseline FENO was ≥ 20 ppb; mean reduction 9.9 (95% CI: 8.7–11.4) ppb.

Conclusion:  FENO 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 FENO value at 1 min post-exercise compared to pupils without AR symptoms. These findings confirm that children should refrain from physical activity before FENO 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.

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