Chlorine and asthma link?

Pools linked to asthma
02 February 2006
By KRISTI GRAY



Splashing around in the local indoor paddling pool is all part of childhood, but it could be contributing to the world-wide asthma epidemic, research suggests. The research has found frequent swimming in indoor chlorinated pools as a child can cause asthma later. Children under two years were particularly at risk because their lungs were still developing. Despite the findings, New Zealand experts still believe swimming is the best exercise for asthmatics.

Belgian researcher Alfred Barnard looked at 340 schoolchildren and found a strong relationship between exposure to chlorine and airway inflammation in children who had taken swimming classes when they were little. ?Results showed 30 per cent of children predisposed to allergies such as asthma were at significant risk. Children who had been swimming in indoor paddling pools where chlorine was highest were most of risk.

The medical director of the New Zealand Asthma and Respiration Foundation, Professor Robin Taylor, said the study raised the need to further explore the connection between indoor swimming and asthma. However, he would not recommend a shift in the current policy of promoting swimming as one of the best forms of exercise for asthmatics.

"It is important for asthmatics to maintain exercise in the same way as for non-asthmatics, and unlike 40 years ago, we certainly encourage them to exercise as much as possible," he said. Not all exercise was easy for asthmatics, Taylor said.

In activities such as running, breathing through the mouth could cause cold, dry air to go straight into the lungs. For asthmatics, this could spark a spasm in the bronchial tubes and bring on wheezing. Air became humidified and warmed when breathed through the nose and this was better for an asthmatic when it reached the lungs.

"Air around swimming pools is already humidified, so when an asthmatic starts to exercise, the air they pull into their lungs is less likely to cause problems," he said. "The quality of air in a swimming pool is much less provocative and more benign for the asthmatic."

Taylor sounded a warning after reading the research. "If we now find children are also breathing in chemical substances which may be linked to causing asthma, we may need to reposition the wisdom of encouraging swimming," he said.

Pioneer Leisure Centre pool team leader Rod Carter said modern indoor pool water-purification methods had greatly reduced the amount of chlorine needed. Chlorine acted with organic matter such as urine in the water to produce chloramine, which sat above the water's surface and when breathed in could cause reactions such as an asthma attack, Carter said. But the main Christchurch City Council pools now used an ozone system for water treatment, so only low-strength chlorine was required and fewer chloramines were produced. "We just don't see asthma attacks at the pool now," Carter said. "This is because children are much better educated about using their inhalers and because of our water treatment."

Swimming New Zealand national educator Ally Todd said many public pools were moving away from traditional full-strength chlorine treatment and looking at methods such as UV treatment. The benefits of swimming far outweighed the negative side, especially for asthmatics, Todd said.