RT Journal Article SR Electronic T1 Differences in nitric oxide airway diffusion after maximum oxygen uptake test in asthmatic and nonasthmatic elite junior cross-country skiers JF ERJ Open Research JO erjor FD European Respiratory Society SP 00378-2020 DO 10.1183/23120541.00378-2020 VO 7 IS 1 A1 Marieann Högman A1 Lars Wedholm A1 Tomas Carlsson A1 Magnus Carlsson A1 Michail Tonkonogi YR 2021 UL http://openres.ersjournals.com/content/7/1/00378-2020.abstract AB Asthma is common in cross-country skiers and is often treated with β2-agonists and inhaled corticosteroids (ICS). Exhaled nitric oxide (NO) is often used to guide ICS treatment in asthma. This study investigated the change in pulmonary NO dynamics before and after a maximum oxygen uptake (V′O2max) test.An extended NO analysis was performed among Swedish elite junior cross-country skiers (n=25), with and without declared asthma, before and after a V′O2max test using roller skis. Asthma was declared by six boys and two girls among whom five occasionally used ICSs.There were no differences in baseline NO parameters between those with and without declared asthma. The median (interquartile range) diffusion capacity over airway wall (DawNO) was 21 (17–25) mL·s−1, which is much increased for this age group. After the V′O2max test, there were statistically significant differences from the baseline fraction of exhaled NO (FENO50), NO flux from airways, DawNO and alveolar NO values; but not in the NO content in airway wall (CawNO) for all subjects together as one group. However, in the asthma group, differences were only seen in FENO50 and CawNO.Interestingly, a majority of the subjects had an increase in the DawNO. An increase in DawNO has been found with allergic asthma together with elevated CawNO. The skiers did not have elevated CawNO, which indicates an absence of inflammation in the airway wall. Modelling of lung NO production clearly shows that the asthma among our skiers is distinct from the allergic asthma in nonathletes.NO pulmonary dynamics of junior cross-country skiers with asthma respond differently to the V′O2max test than in those without asthma. Analysis of airway inflammation should be considered before inhaled corticosteroids are prescribed. https://bit.ly/3eWB1JZ