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 (T(NO)) and nasal (N(NO)) 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 (FEV(1))).


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 T(NO) or N(NO) 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.
Department of Medicine and Therapeutics, Ninewells Hospital, University of Dundee, UK.
K L
KL
Clearie
S
S
Vaidyanathan
P A
PA
Williamson
A
A
Goudie
P
P
Short
S
S
Schembri
B J
BJ
Lipworth
D000293:Adolescent; D001250:Asthma, Exercise-Induced / Q000453:epidemiology* / Q000209:etiology; D056352:Athletes; D002648:Child; D002713:Chlorine / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D012137:Respiratory System / Q000187:drug effects* / Q000503:physiopathology*; D013147:Spirometry; D013550:Swimming; D055815:Young Adult
D002713:Chlorine