Disconnect between standardized field-based testing and mannitol challenge in Scottish elite swimmers.
Elite swimmers have high rates of rhinoconjunctivitis and exercise-induced bronchoconstriction. Moreover, exposure to chlorine and chlorine metabolites is known to induce bronchial hyper-reactivity.



To assess the early and late effects of chlorine and exercise on the unified airway of elite swimmers, and to compare the response to mannitol and field-based exercise challenge.



The Scottish national squad underwent exhaled tidal (FE(NO)) and nasal (N(NO)) nitric oxide measurement, peak nasal inspiratory flow (PNIF), and forced expiratory volume in 1 s before, immediately after, and 4-6 h post-swimming. A sport-specific exercise test was carried out during an intensive lactate set (8 min at >/=80% maximum hear rate). All swimmers underwent mannitol challenge, and completed a health questionnaire.



N=61 swimmers were assessed: 8/59 (14%) of swimmers had a positive mannitol challenge. Nine out of 57 (16%) of swimmers had a positive exercise test. Only one swimmer was positive to both. Swimmers with a positive mannitol had a significantly higher baseline FE(NO) (37.3 vs. 18.0 p.p.b., P=0.03) than those with a positive exercise challenge. A significant decrease in FE(NO) was observed pre vs. immediate and delayed post-chlorine exposure: mean (95% CI) 18.7 (15.9-22.0) p.p.b. vs. 15.9 (13.3-19.1) p.p.b. (P<0.01), and 13.9 (11.5-16.7) p.p.b. (P<0.01), respectively. There were no significant differences in N(NO.) Mean PNIF increased from 142.4 L/min (5.8) at baseline to 162.6 L/min (6.3) immediately post-exposure (P<0.01). Delayed post-exposure PNIF was not significantly different from pre-exposure.



No association was found between mannitol and standardized field-based testing in elite swimmers. Mannitol was associated with a high baseline FE(NO); however, exercise/chlorine challenge was not. Thus, mannitol may identify swimmers with a 'traditional' inflammatory asthmatic phenotype, while field-based exercise/chlorine challenge may identify a swimmer-specific bronchoconstrictor response. A sustained fall in FE(NO) following chlorine exposure suggests that a non-cellular, perhaps neurogenic, response may be involved in this group of athletes.
Clearie
K L
KL
Asthma & Allergy Research Group, Department of Medicine and Therapeutics, Ninewells Hospital & Medical School, University of Dundee, Dundee, Scotland, UK.
Williamson
P A
PA
Vaidyanathan
S
S
Short
P
P
Goudie
A
A
Burns
P
P
Hopkinson
P
P
Meldrum
K
K
Howaniec
L
L
Lipworth
B J
BJ
D000293:Adolescent; D001250:Asthma, Exercise-Induced / Q000175:diagnosis / Q000209:etiology*; D001985:Bronchial Provocation Tests / Q000379:methods*; D002713:Chlorine / Q000009:adverse effects*; D005080:Exercise Test; D006801:Humans; D008353:Mannitol; D009569:Nitric Oxide / Q000032:analysis; D012606:Scotland; D012680:Sensitivity and Specificity; D013550:Swimming; D013997:Time Factors
D009569:Nitric Oxide; D008353:Mannitol; D002713:Chlorine