The prevalence of exercise-induced bronchoconstriction (EIB) is 10% in the general population, up to 90% of those with asthma, and 50% of those with allergic rhinitis.
Chlorine metabolites and training load may produce exercise-induced bronchospasm (EIB) in elite swimmers. The aim of this Scottish study was to assess the combined effects of chlorine and exercise on the unified airway of adolescent elite swimmers.
A squad were assessed during an indoor pool session. Athletes trained at least 8 hr per week and underwent pre and post a 2 hr session:
- tidal (TNO) and nasal (NNO) exhaled NO
- peak nasal inspiratory flow (PNIF)
22% of swimmers had known asthma; 36% had a positive exercise challenge; 50% complained of symptoms suggestive of EIB.
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.
The authors concluded that 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.
Exercise-induced bronchospasm (EIB) (click to enlarge the image):
Effects of chlorine and exercise on the unified airway in adolescent elite Scottish swimmers. K. L. Clearie, S. Vaidyanathan, P. A. Williamson, A. Goudie, P. Short, S. Schembri, B. J. Lipworth. Allergy. 2009.
Swimming may not increase the risk of asthma or allergic symptoms http://goo.gl/ZdiG5
High prevalence of asthma among elite swimmers http://goo.gl/Sm8Fo
Swimming in indoor chlorinated pools associated with airway changes similar to mild asthma, but w/o hyperresponsiveness. JACI, 2011.
Lung function declines in volunteers after exposure to trichloramine (NCl3) in indoor pool http://buff.ly/QjZiHE
Image source: Wikipedia, a Creative Commons License.