Children who swim in chlorinated pools weekly or fortnightly have a higher risk of developing lung diseases including asthma, a study in the British medical journal Occupational and Environmental Medicine found.
The inhalation of chemicals used to destroy microbiological germs in swimming pools may be responsible for the surge of childhood asthma in developed countries, according to Alfred Bernard of the toxicology unit at the Catholic University of Louvain in Brussels.
Disinfectants contain compounds that generated potentially harmful gases when they come into contact with urine or sweat from swimmers. The by-product trichloramine is thought to be responsible for eye and respiratory tract irritation experienced by lifeguards and other pool users, the researchers said.
Swimming is recommended for asthmatics as hot humid air in pools compensates for the effects of exercise, but not if the air is laden with toxins, the authors said. Children who swam most frequently had damage to their lungs similar to that in regular smokers, the researchers found.
Levels of trichloramine vary depending on ventilation, on how crowded a pool is and how clean the swimmers are. The researchers measured levels of lung proteins, which are linked to cellular damage, in the blood samples of school children.