Impact of a Short-Term Water Abstinence on Airway Hyperresponsiveness in Elite Swimmers.

OBJECTIVE: To investigate the effect of a swimming break on airway hyperresponsiveness (AHR) and to evaluate perception of bronchoconstriction-related symptoms after methacholine challenge testing (MCT).

DESIGN: Observational, controlled study.

SETTING: University department.

PARTICIPANTS: Overall, 25 healthy, elite, competitive swimmers aged ≥14 years from the local Olympic training center and 25 healthy control subjects.

INDEPENDENT VARIABLE: Duration of water abstinence.

MAIN OUTCOME MEASURES: Primary outcome measures were a positive MCT with a provocation dose (PD) and the perception score of bronchoconstriction-related symptoms at visit 1 (V1, training period) and visit 2 (V2, after swimming break).

RESULTS: In the study, 13 swimmers (52%) and 10 control subjects (40%) showed AHR. The PD did not differ significantly between V1 and V2 in the swimmers (P = 0.81) or in the control subjects (P = 0.74). No correlation of fraction of exhaled nitric oxide with the PD could be established in both the groups (swimmers: P = 0.97; controls: P = 0.99). The majority of swimmers with AHR were asymptomatic, and only minimal differences in perception of bronchoconstriction-related symptoms between swimmers and control subjects were observed (P = 0.23).

CONCLUSIONS: A swimming break of 25 ± 8 days does not seem sufficient to significantly reduce AHR in elite swimmers. Thus, relevant and systematic effects of short-term water abstinence on AHR seem unlikely. Because the majority of swimmers remain asymptomatic, AHR may escape routine screening examinations. The impact of AHR on athletic performance and the long-term clinical consequences remain to be clarified.