Monitoring Lung Function of Asthmatic Swimmers in Public Swimming Pools

There is controversy over the effect that swimming in indoor pools can have on lung function and on bronchial inflammation parameters in asthma. The objective of this study was to observe the effect of recreational swimming in public indoor pools on changes in functional and inflammation parameters in patients with asthma.

A prospective observational study, including asthmatics who were regular swimmers in indoor pools, and swimmers in the same pool without respiratory involvement. In both groups, baseline spirometry and measurement of fractional exhaled nitric oxide (FENO) were performed minutes before and after swimming. Additionally, the physicochemical parameters of the water were analyzed, including the disinfectant products used.

Twenty five asthmatic swimmers (intermittent 53%; mild persistent 29.4%; moderate persistent 17.6%) and 50 healthy swimmers, mean age 40.8 ± 10.8 years, were included in the study. The mean immersion time was similar for both groups (asthma 31.9 ± 10, control 32.4 ± 12 min). The analysis of the water showed no differences in its composition or characteristics between the different pools. In asthmatics, FENO decreased significantly (28.7 ± 17.8 pre vs 23.7 ± 15.5 post, p < 0.001) after immersion, with no changes in the other functional parameters. In non-asthmatic subjects, increased vital capacity (p < 0.05) and volume expired in one second (p < 0.04) improved significantly after immersion, and FENO decreased (p < 0.01). No significant differences were found in functional or inflammation variables between the two groups after bathing.

In patients with intermittent and persistent asthma, no immediate functional or inflammatory alterations have been observed after bathing in legally regulated public swimming pools.