The Truth About Chlorinated Pools and Asthma

Swimming in Chlorinated PoolSwimming is my favorite form of exercise. To feel so weightless while working every muscle in your body is invigorating to me. I’ve been on swim teams since I was twelve, and as an adult I try to swim three times a week; and almost every pool I have used has been indoors.

Is it a miracle I haven’t developed asthma?

For years, studies have shown that children who spend a lot of time in indoor pools have a higher risk of developing asthma than non-swimmers. This is traditionally attributed to the addition of chlorine to the water.

Actually, the problem with chlorinated pools isn’t the chlorine itself, but the gases produced when it combines with organic chemicals like sweat and saliva.

A study in Spain tested a group of 49 participants who either swam or worked at a chlorinated pool. Thirty minutes later, all participants’ urine showed signs of haloacetic acids (HHAs), a dangerous chemical restricted by health and environmental agencies because of its association with cancer and birth defects. HHAs are created when disinfection products (like chlorine) mix with naturally-occurring matter in water.

In another study by Dr. Simone Carbonnelle, 226 healthy school children were exposed to the air around a swimming pool for about 15 minutes a day. The results showed levels of lung tissue damage directly proportional to the amount of time children spent around the pool – sometimes the amount of damage you would expect to see in a heavy smoker.

So how can you avoid the risks associated with chlorine without giving up the health benefits of swimming? Be choosy where you swim.

First, the air quality of an indoor pool shouldn’t be poor. High humidity levels encourage mold growth, which aggravates the respiratory system. Indoor pools also need to be well-ventilated; airflow about the pool surface helps disperse any dangerous chemicals.

Another solution is to avoid chlorinated pools altogether.

A popular alternative to chlorine pools is saline pools. In these pools, salt is added to the water every few months. It is broken down inside a cell chamber, producing a stream of chlorine gas that sanitizes the pool.

That’s right! Saline pools aren’t chlorine-free. However, they use chlorine in such a way that harmful byproducts like HAAs aren’t a factor. If the chlorine mixes with organic matter to produce any harmful substances, more chlorine is quickly pumped through that destroys them. This eliminates the primary health risk of chlorinated pools.

If you have high sensitivities to allergies to chlorine, consider other types of pools. Some pools use ionization (positively-charged coils that purify the water). Others use activated carbon filters to keep harmful chemicals from releasing into the air.

But remember: if you have reactions to chlorinated pools, there is a good chance you are reacting to other chemicals and byproducts in the pool – not the chlorine itself.

For a directory of non-chlorine pools around the world, go to

So how does an avid swimmer like me avoid asthma for over fifteen years? Lucky genes could be a part of it. But I also make a point to swim in saline pools, and before joining, I always ask how they maintain the air quality.

Do you or your children swim in chlorinated pools? Have you switched to saline pools or some non-chlorine alternative? Tell us your story in the comments section below!

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