Summer Brings Swimming, Chlorine May Bring Asthma


Florida is a weird state, and it’s mostly misunderstood by non-residents. Tourists think we’re all Universal Studios and Disney World. Beach vacationers remember condos and palm trees only, and snowbird retirees stick to their central and south-central coastal communities. Up here in northwest Florida, though, is like a completely different state. We’re more Deep South than Disney, and the climate surprises new residents and first-time visitors.

Our weather is similar to southern Georgia and Alabama and more seasonal by far than south Florida. Our summers are a little longer than the middle portions of the U.S. and very humid, but shorter than say, the Tampa Bay area where I used to live and where we used to swim right up through November. Here, while I may venture into a sun-warmed pool in May, the water in the Gulf of Mexico is too cool for my thin Florida blood until June. Yesterday, for example, the Mother’s Day pool gathering at my mom’s was tolerable only because she heats the water with solar panels until the summer sun gets hot enough to do the job.

But once the summer does hit its stride, with the July and August heat index reaching 100+ and a walk from the front door to the car leaving us sweaty, we more or less don’t venture outside until September unless we’re immersing ourselves in a large body of water.

I’ve always been ambivalent about what swimming pools mean to AG’s asthma.

Swimming requires taking deep breaths and holding them at regular intervals, increasing lung capacity and training lungs into good breathing patterns for regular people. So it makes sense that swimming may actually help asthma. No, you can’t run, bike, walk, or swim your way out of this disease that involves a very real physiological component, but it’s thought that the regular breathing associated with swimming helps overall lung health, which may in turn help the lungs through flares.

Sites like the AAFA say,

Swimming that involves breathing warm and moist air, is often well tolerated.

Last year I wrote an article for that explains how this environment, according to researchers like Brent S. Rushall, Ph. D., and Larry Weisenthal, M.D., in Swimmer’s Asthma: The Serious Health Problem with Chlorinated Pools, can actually make indoor pools dangerous for asthmatics. Inhaling high concentrations of chloramines, produced when chlorine interacts with contaminants in the water, is known to damage the respiratory tract. Since public pools tend to over-chlorinate, most indoor pools don’t have stellar ventilation systems and chlorine gas is heavier than air, the highest concentration of toxins is close to the surface of the water, where you swim. The higher the concentration, the worse the potential lung damage.

European research from last year also shows higher numbers of childhood asthma in areas with more indoor pools, and this study may support a relationship between indoor pool use and childhood asthma, although it’s not conclusive.

Outside public pools aren’t necessarily worry-free, either, since they’re also usually over-chlorinated. While breezes blow the chlorine gases next to the water surface away, pools with high sides on still, humid days can trap the gases close to the water surface just like in poorly ventilated indoor pools. (Private pools probably don’t pose the same risk, since homeowners don’t tend to over-chlorinate their own pools.)

Want more data?

The 2000 U.S. Olympic swim team contained more asthma sufferers–one-quarter of the whole team–than any other U.S. team that year. This isn’t evidence that indoor pools cause asthma, either, but it’s noteworthy since Olympic swimmers usually train indoors.

Now, more recent research is adding to the case. Just last month, a Norwegian study pointed to possible links between baby swimming and childhood asthma. Again, nothing definitive here, although my children certainly align with the results. AG has been in pools since she was two months-old, but her non-asthmatic sister didn’t get in for the first time until right around her seventh month.

So even though we practically live in the water during the summer, with all the conflicting evidence about swimming pools, I make a few compromises:

1. Natural bodies of water over pools if I have the choice. With beaches like this one and the Blackwater River–one of the purest sand-bottom rivers in the world–both only half and hour from my house, this isn’t really a sacrifice.


2. No indoor pools. Not ever.

3. No outdoor pools with a strong chlorine smell. My mom helps out on this one, too, by not over-chlorinating her pool water and letting me know when she’s just added some so I don’t bring AG over right away.

84 responses to “Summer Brings Swimming, Chlorine May Bring Asthma”

  1. Asthmagirl says:

    Not surprisingly, I’m agreeing with you on this one. I attempted to swim in a hotel pool in Canada a few months after diagnosis. I sounded like a sea lion… my cough had turned into a non stop bark and I could not catch my breath. It wasn’t until I got back to the states and spoke with my doctor that I understood what the issue was. One of those things I wish they told you when they diagnose you!

  2. AndieBeck says:

    Wow – I had no idea. Thank you soooo much for this info. As I live in Canada and the outdoor swim season is short, we’ve been in the indoor pool at the rec centre quite a bit lately. I had never heard of this before but it really makes sense. I’ll have to pay closer attention if/when we go swimming indoors again. Unfortunately we don’t have a lot of options for natural bodies of water for swimming where I live!

    Hmm, more arguments in favour of putting in our own pool someday … hopefully a salt water one ;)


  3. Amy says:

    AG has never been in an indoor pool, but that’s b/c we live in Florida, not because I’ve known about the chlorine issue her whole life. Interestingly, when I think back to her early years swimming, she DOES tend to cough in public pools but never did in ours (at our old house).

    Andie, I think you could definitely make a case for your own pool based on this, lol.

  4. Hannah says:

    I am a competetive swimmer in England and swim daily. last year there was too much chlorine in the pool and 3 of us especially, reacted so were rushed to hospital. this happened again 2 days ago but this time i was worst effected. the next day i trained again but my chest was very tight and had to get out early. today i went to the doctors and he said i have asthma and gave me an inhaler. All the pools we train in are indoor. What can be done to reduce the chances of it happening again?

  5. Amy says:

    Hi, Hannah.
    Sorry about your diagnosis, but so glad you stopped by. If the dr. gave you just the one inhaler, I’m assuming it’s a reliever inhaler. Here in the U.S. it’s called albluterol, but I believe the UK uses the other term–salbutamol.

    Some asthma sufferers use their inhalers right before experiencing a known trigger (like indoor pools) rather than after symptoms occur. My daughter, for example, tends to have asthma flares on planes, so she uses her inhaler right before she gets on to try preventing flares.

    Another thing you could do is ask the dr. about a controller corticosteroid inhaler as well. These keep the inflammation down so that any triggers you do encounter shouldn’t affect you as much–especially if your trigger is chlorine and you’re in pools all the time.

    Hope that helps!

  6. Sharon Mom says:

    Last year, my 8 year-old son had a bad case of bronchitis at the end of the summer… and pool season was cut short, as the allergist advised. Then, I was suspicious that the chlorine was linked to the bronchitis. Now this year, he immediately began coughing when he went in the town pool (heavily chlorinated, to be sure) for the first time this season, and subsequently coughed when he went back in again the second time last night…and now he woke up with the croup and a very low peak flow. Asthma again! Now, I have no doubts about the asthma-chlorine link for him. And we haven’t even ventured to the indoor pool for his swim lesson yet! I think he may be missing out this week.

  7. Julie says:

    My son, 9, has complained that swimming in our local indoor pool makes it hard for him to breathe. He has seasonal allergy related asthma symptoms that usually appear in the fall or after a cold. But this indoor pool seems to bother him a great deal–only when we’re there, and only after about half an hour. My question is, the research I’ve read on the chlorinated indoor pool/asthma link talks about people who spend hours per day swimming. His response is pretty quick and we only go once a week. Could his complaint be chlorine related, despite the fact that we actually spend relatively little time at the pool?

  8. Amy says:

    Hi Julie,
    I’m wondering if your research is talking about people who develop asthma after hours and hours in heavy chlorination.

    If your son has asthma already, then IMO he could be flaring b/c of the chlorination since flares can happen with quick exposures to any triggers, if that makes sense. Ask your son’s doctor, too, if he thinks the pool is causing problems–the dr. may recommend pre-treating with an inhaler if you want to stick with that pool.

    Hope that helps!

  9. Keith Forte says:

    After doing some work with the American Chemistry Council, I can assure you that, despite what many swimmers assume, the major cause of these problems is too little free chlorine rather than too much! Additionally, due to sanitation practices, the general public is not exposed to molecular chlorine.

  10. Raegen says:

    I was a competitive swimmer for 9 years from 1987-96′ with no family history of asthma. After my 1st year of training I developed asthma which got progressively worse with time & now must take bronchial steroids daily & am in hospital every year for treatment.
    I have a feeling if government research ever spends enough money to become finally conclusive, the municipally run swimming pools could have huge lawsuits on their hands.
    I urge all to remain vigilant as this is a serious health concern which could have been prevented before the big drug companies had the privilege of relieving asthma sufferers of their money to pay for NEEDED drugs.

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