London: Chlorine used in disinfecting swimming pools might be a cause of asthma in children who take swimming classes regularly, according to a research study.

The findings said nitrogen trichloride, reportedly a highly concentrated volatile by-product of chlorination, is the likely culprit.

The research, published in 'Occupational and Environmental Medicine', said, while swimming, the kids inhale nitrogen trichloride, which is generated during contact between chlorine and organic matter such as urine or sweat.

The research team measured levels of some of the lung proteins directly connected to cellular damage in the blood samples of around 226 healthy school-going children, both in rural and urban areas.

The sampled children swum regularly at indoor pools, weekly or fortnightly, since their childhood.

The findings showed that regular swimming was directly related with the destruction of the cellular barriers protecting the deep lung, thereby making them "leaky" and hence allowing the passage of allergens. It was also discovered that those children who swam more frequently had more damage in the lungs, equivalent to that found in the lungs of regular smokers.

The effects were the same for children irrespective of the place where they lived. The impact was comparatively strong in younger children.

However, the researchers said swimming is recommended to those suffering from asthma because the hot humid air in the swimming pools compensates for the effects of exercise provided the air is not laden with toxins. The levels of trichloramine could vary depending on the number of persons using the pool, cleanliness of the swimmers, and the level of ventilation in and around the swimming pool, they added.

ANI