Swimming pool, respiratory health, and childhood asthma: Should we change our beliefs?

Abstract

Summary. Swimming is often recommended as a sport because of its several benefits to health. It is also recommended in asthmatic children as a sport with a lower potential for prompting exercise-induced asthma. However, there is growing interest in the potentially harmful effects of repeated respiratory tract exposure to chlorinated products and the problem of possible swimmingrelated health hazards is gaining importance at international level. It is already known that acute exposure to chlorine gas as in swimming pool accidents causes lung damage and also that elite swimmers may have increased airway inflammation and bronchial hyperreactivity, probably as a result of repeated exposure to chlorine derivatives. Recently some studies have been conducted to investigate whether repeated exposure to chlorine by-products in recreational swimmers might also lead to lung damage. In addition, some studies have been lately published on the even more debated issue of the possible harmful effects of baby swimming on respiratory health. This article reviews and discusses data from the literature on the effects of chlorine derivatives in different categories of people routinely attending swimming pools. The need for longitudinal studies is emphasized to definitely clarify any role of chlorinated swimming pool attendance in the development of asthma in recreational swimmers.

Overview of Disinfection By-products and Associated Health Effects

“…Due to the cross-sectional design of these studies, however, a healthy worker effect cannot be ruled out. Several studies have shown a higher prevalence of asthma among swimmers compared to other athletes [85], but the direction of the association is not clear, given that swimming is a recommended sport for asthmatics [85,86].…”

Chlorine Gas Exposure Causes Systemic Endothelial Dysfunction by Inhibiting Endothelial Nitric Oxide Synthase–Dependent Signaling

“…We have demonstrated that exposure of rats and mice to Cl 2 leads to extensive injury to airway and alveolar lung epithelia, decreased surfactant function, decreased ability of alveolar epithelial cells to actively transport sodium ions and clear fluid, and decreased levels of ascorbate and a decreased ratio of glutathione to oxidized glutathione in BAL and lung tissues (8)(9)(10). These inflammatory responses continue to induce injury after cessation of Cl 2 exposure, culminating in acute lung injury, adult respiratory distress syndrome, and reactive airway syndrome (9,(11)(12)(13)(14)(15)(16)(17). The precise mechanism of this post-Cl 2 exposure injury remains unclear and important to address because this aspect of Cl 2 -induced injury is the primary goal for therapies.…”

Swimming Pool Attendance, Asthma, Allergies, and Lung Function in the Avon Longitudinal Study of Parents and Children Cohort

“…Studies conducted in Germany (11,12), Italy (13), and Spain (14) did not find an increased risk of asthma among children attending swimming pools. Despite the conflicting results, there is agreement on the complexity of the potential role of swimming in asthma etiology and the important public health implications (1,(15)(16)(17). Asthma is among the most common chronic diseases in children (18), and swimming is one of the most practiced sports in western countries (19), where sedentarism and obesity are increasing, especially among children (20).…”