Chlorinated pool air, airway mucosal immunity, and respiratory health in competitive swimmers: a mini review.

Chlorinated swimming pools are a routine training setting for competitive swimmers, but the breathing zone just above the water surface can contain a variable mixture of volatile disinfection by-products. For athletes who train at high ventilation rates, trichloramine and related compounds may be delivered repeatedly to the airway mucosa, particularly during prolonged sessions with mouth breathing and high humidity. This setting is relevant to immunology because the conducting airway acts as a mucosal barrier as well as a ventilatory conduit, coordinating epithelial integrity, innate immune signaling, allergic responses, and protection against respiratory pathogens. Evidence from swimmer cohorts, pool-worker studies, exposure assessments, and experimental models links chlorinated pool exposure with mucosal irritation, altered lung permeability, airway hyperresponsiveness, neutrophilic or eosinophilic inflammation, and asthma-like symptoms in susceptible individuals. The evidence is nevertheless uneven, partly because studies differ in exposure measurement, training load, atopy, infection status, and biomarker timing. A review focused on this narrow environment may help connect pool chemistry and ventilation with athlete behavior and airway immune outcomes. This mini review shows evidence on chlorinated pool air, airway mucosal immunity, and respiratory health in competitive swimmers, with attention to mechanisms that are clinically relevant for athlete monitoring. This review applies an exposure-barrier-phenotype framework that separates acute peaks from cumulative exposure, ventilation and bather-load effects, and host phenotypes. It also integrates emerging epithelial alarmin and barrier mechanisms, distinguishes disease initiation from exacerbation of asthma or rhinitis, compares pool-derived irritants with common air pollutants, and proposes standardized exposure, biomarker, stratification, and prevention priorities.