Swimming pool chlorine augments asthma risks


Asthma is a chronic inflammatory disease that causes the airways of the lungs to tighten and swell. These include: swelling of the lining, tightening of the muscle, and increased secretion of mucus in the airway.  According to NIH (National Institute of Health), Asthma ranks among the most common chronic conditions in the United States, affecting an estimated 14.9 million persons in 1995 and causing over 1.5 million emergency department visits, about 500,000 hospitalizations, and over 5,500 deaths.


Last time I wrote about warning signs of asthma and how to gain control over child’s asthma.  Recently I came across a Belgian study which says that swimming in chlorinated pools may increase the risk of getting asthma, especially in children, along with respiratory allergies like hay fever.  Let us take a look at the study and its findings.


JacuzziWhy is chlorine used in swimming pools?

Chlorine is the chemical most often used to keep swimming pools and Jacuzzis free of bacteria that can be hazardous to humans. Chlorine kills bacteria though a fairly simple chemical reaction. The chlorine solution you pour into the water breaks down into many different chemicals, including hypochlorous acid (HOCl) and hypochlorite ion (OCl). Both kill microorganisms and bacteria by attacking the lipids in the cell walls and destroying the enzymes and structures inside the cell, rendering them oxidized and harmless.


danger-chlorineHow much risk is associated with swimming in chlorinated pools?

The study that was conducted at the Catholic University of Louvain in Brussels, Belgium, revealed that the teenagers who spent more than 100 hours swimming in chlorinated pools, either indoors or outdoors, had more than eight times the risk of having asthma.   Dr. Alfred Bernard, Technology and Research Director, said that “The impact of these chemicals on the respiratory health of children and adolescents appears to be much more important — at least by a factor of five — than that associated with secondhand smoke“.


What are more details around the study?

The study was conducted on 847 Belgian teenagers that were aged 13 to 18.  733 teenagers swam in chlorinated swimming pools for varying amount of time against 114 teenagers who swam in pools that were sanitized with a mix of copper and silver.  Main results from the study include: asthma

    class="MsoNormal" style="text-align: justify; line-height: 150%; margin: 0in 0in 0pt; color: black; mso-list: l0 level1 lfo1; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; tab-stops: list .5in;">Teens who swan in chlorinated water for more than 100 hours were three to six times more liable to suffer from hay fever.
  • Teens that swam more than 1,000 hours in chlorinated pools were two to three times more susceptible for allergic rhinitis.
  • Teens who swam in chlorinated pools for between 100-500 hours, six percent had current asthma, compared with only 1.8 percent, of those who had spent less than 100 hours in chlorinated pools.
  • Also, the chances of asthma increased with exposure time to chlorinated water, such as 500 -1000 hrs of exposure to chlorinated 6.4% of teens exhibited asthma, whereas for more than 100 hours numbers rose to 11.9%. 

The risk of asthma and allergy was not influenced by swimming in copper-silver sanitized pools and children without allergic tendencies were not at increased risk of developing allergies.


What is the reason for increase in asthma due to chlorinated water?

Researchers do not have a clear cause for their observation.  One of the leading theories include changes cause in the airway due to the chlorine based chemicals in water or in the air over the swimming pool, which promotes development of allergic diseases.  Dr. Bernard further stated that “It is probably not by chance that countries with the highest prevalence of asthma and respiratory allergies are also those where swimming pools are the most popular,” said Bernard.




Swimming is a very good exercise. You must be encouraged by success of Michael Phelps and keen to see your kid zip through swimming pool.  The Belgian study cautions that we must limit the exposure to chlorinated water to teens and opt of pools that are sanitized by much milder chemical than chorine based compounds.  


Healthy Swimming!



7 Responses

  1. Robert says:

    I’ve been reading much info. about the swimmer asthma and frankly I’m a bit concerned. Not so much with swimming but the articles themselves. 100 hours? Over what period, a day, month, year? Let me take a look at the chemical readings of the pool. How was the health of these people before entering the pool? Many questions and few answers.

    I take care of our YMCA pool in Oregon and we don’t have this problem. That’s because the pool is balanced correctly and properly maintained.

    The issue with this chlorine allergy and asthma is not because the pool uses chlorine, but because not enough chlorine is used. When there is organic matter (sweat, urine, etc…) in the pool it binds with the chlorine and produces chloramines. These chloramines in the water are what causes that bad chlorine smell and it happens when there’s not enough chlorine in the pool to kill the organisms.

    Commercial pools should keep the chlorine level between 3.5 -4.5ppm and pH around 80-100ppm. Have good ventilation and fresh air for indoor pools.

    If pool operators would follow simple guidelines, I believe you would see a drop in this “chlorine allergy” hysteria.


  2. I knew this was true I just had not had a chance to look into it yet. You should see more articles like this every where online to get the word out so everyone knows before they let there kids risk asthma attackes with out having their inhalors poolside.

  3. A writer’s mind seems to be situated partly in the solar plexus and partly in the head. ~Ethel Wilson

  4. Kids Pool says:

    Very informative post indeed. Maybe I should get more information about this topic. Thanks for sharing this one.

  5. Good day, I am having my first go with private pools. We got a new house in wintertime that has a swimming pool which I understand hasfailed to be remedied for more than a year or so. I opened the pool 2 weeks ago and now have been trying to fix it. It began with a good deal of algea in the bottom that we removed away. It is now soft green, yet it is not getting better. I found a business not far away, has anyone come across these people or recommend any others? Affordable Pool Service & Repair, 2942 N 24th St #114, Phoenix, AZ 85016, (602) 910-2295. Any tips is going to be valuable.

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