Swimmer's asthma

Did you know that some studies have established a direct correlation between asthma in young children and high-level swimmers and the chlorine found in swimming pools? Some European government agencies also recommend caution and prevention in children under 2 years old. Caution is therefore advised if you suffer from or are predisposed to respiratory problems. Solution for the most diligent: choose a swimming pool using a different disinfection system.

Chlorine increases risk of asthma

Studies agree that chlorine fumes released in swimming pools increase the risk of asthma.

According to a study carried out in the Netherlands among 600 swimming instructors working in indoor swimming pools (1), it appears that in these people exposed all day to chlorine, respiratory symptoms are more severe and more frequent than in the general population. The risk of sinusitis, hoarseness and bronchial hyperactivity is increased by 40%. An Italian study this time (2) looked at thirty competitive swimmers with an average age of 14, all free of asthma. After undergoing respiratory tests, it turns out that 73% of them were sensitive to classic airborne allergens, almost twice as many as in the general population, and 50% of them suffered from bronchial hyperactivity. These two factors are predictive of the onset of asthma.

According to a third study presented at the 17th Congress of the European Society of Respirology, the risk of suffering from asthma is multiplied by three in children and adolescents who regularly visit swimming pools disinfected with chlorine. And this conclusion is also valid in outdoor swimming pools, whereas until now, it was thought that only indoor swimming pools could promote the onset of asthma.

This study involved 850 adolescents with an average age of 15, attending 3 middle schools where swimming lessons were held in an outdoor pool. Two pools were disinfected with chlorine. The 3rd was disinfected with a copper-silver ionization system and served as a control. Knowing the number of hours spent in the pool, the history of allergies and asthma, the lifestyle, etc., of all the subjects, the researchers came to the following conclusion: the adolescents who had accumulated more than 500 hours of outdoor swimming saw their risk of asthma multiplied by 3, compared to those who had never attended a pool containing chlorinated water.

The real culprits: chloramines

The problem is therefore linked to chlorine, but the responsibility lies more precisely with the irritating gases which come from chlorine and which stagnate above the water, about ten centimetres from the surface, and which are the cause of the characteristic odour of the pools.

In fact, when chlorine comes into contact with nitrogenous substances, that is to say with human secretions (sweat, saliva, urine), a chemical reaction occurs which releases gases which irritate the respiratory tract, in particular chloramines.

In conclusion, you should not give up on swimming, because swimming is a particularly beneficial sport for your health. On the other hand, you should rather opt for a swimming pool that uses a more natural sanitation system such as copper-silver ionization, rather than traditional chlorine disinfection.

• Jacobs JH et al., Eur. Respir. J., 29 (4): 690-8, 2007
• (2) Brusasco V. and Rossi G., University of Genoa, Italy.
• 17th Congress of the European Society of Respirology, September 15-19, 2007, Stockholm, communication by Prof. Nickmilder M., University of Louvain, Belgium.