• bronchial challenge;
  • exercise-induced asthma;
  • nitric oxide;
  • rhinitis

To cite this article: Clearie KL, Vaidyanathan S, Williamson PA, Goudie A, Short P, Schembri S, Lipworth BJ. Effects of chlorine and exercise on the unified airway in adolescent elite Scottish swimmers.


Background:  Chlorine metabolites and high training load may produce exercise-induced bronchospasm (EIB) in elite swimmers. The aim of this study was to assess the combined effects of chlorine and exercise on the unified airway of adolescent elite swimmers.

Methods:  The Scottish Midlands District squad were assessed during an indoor pool session at the National Swimming Academy. Athletes trained at least 8 h per week. Subjects underwent tidal (TNO) and nasal (NNO) exhaled NO and peak nasal inspiratory flow (PNIF) pre and post a 2 h session. A physiological exercise challenge assessed EIB in n = 36 swimmers (>10% fall in forced expiratory volume in 1 s (FEV1)).

Results:  Combined and free chlorine levels (mg/l) were 1.66 and 0.3 respectively. n = 36 swimmers (mean age 13.3 years) were assessed: n = 8 (22%) had known asthma; n = 13 (36%) had a positive physiological challenge; 18 (50%) complained of symptoms suggestive of EIB. n = 10/28 (36%) who did not have asthma were found to have a positive exercise challenge. There was no significant association between reported exercise symptoms and positive exercise test. There was no significant change in TNO or NNO for pre vs postexposure, irrespective of asthma diagnosis or AHR. n = 15 (42%) swimmers complained of worsening nasal symptoms postexposure, but only n = 7 (14%) had a demonstrable fall in PNIF (mean 33 l/min). No significant association was found between PNIF and symptoms.

Conclusions:  Combined exposure to chlorine and exercise did not affect surrogate markers of inflammation in the unified airway. There was a high prevalence of undiagnosed EIB.