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Health Effects of Chlorine Swimming Pools & How to Stay Healthy


Nothing says summer like jumping in a nice cool pool to beat the heat. Unless you’re my brother. He never liked swimming pools because, in his view, swimming in a pool was essentially the same thing as swimming in pee.

But that’s just him being a germaphobic stick in the mud, right? Maybe…and maybe not. What’s really in the pool water your kids are splashing in? Is pee really a problem? Are there health effects of chlorine swimming pools? Let’s dive in.

Chlorine at Work

It’s pretty basic logic that a big pool of water with all kinds of people coming and going will have a certain level of yuck. You wouldn’t say your used bathwater or a bucket of standing water outside is exactly clean, would you? Whether we like it or not, we’re full of germs, and when you put us together in a thing of water, you get people-germ soup.

And that’s where the chlorine comes in. Chlorine kills a lot of those germs and helps keep pools from turning into giant scum holes. It’s not perfect, but it makes pools relatively free of harmful pathogens that might make people sick – mostly with gastrointestinal illnesses. And, yes, it’s a chemical, but on it’s own, it’s not particularly hazardous to your health in the doses used in pools (properly maintained pools, of course). In fact, contrary to common belief, chlorine isn’t exactly to blame for your eyes turning red after a day at the pool. The real reason is a bit more troubling.

That’s right. Urine. Pee. So it’s not necessarily what pool managers are putting in the water, but what YOU and other swimmers are putting in.


While extended or frequent exposure to chlorine in a pool can be irritating to the skin or even the throat, it’s not really dangerous for our long-term health. But studies have found that when chlorine combines with compounds in things like urine, sweat, skin cells, saliva, cosmetics and fecal matter (fun fact: according to the CDC, people have about 0.14 grams of fecal matter on their bottoms at any given time), more harmful products are formed. In fact, a 2010 study identified more than 100 chemical byproducts in pools using chlorine as a disinfectant.

These products, called chloramines or DBPs (disinfectant-by-products), are not yet fully understood, but have been linked to a variety of possible health effects. And they can enter your body through three different pathways when you swim:

  1. They can be ingested when you swallow water.
  2. They can become airborne and then inhaled.
  3. They can be absorbed through the skin.

According to WebMD, chloramines can cause stinging of the eyes, nasal irritation and breathing problems. Other researchers are investigating possible links between DBPs and asthma or other respiratory issues.

Purdue University reported on studies into DBPs, particularly the DBPs cyanogen chloride and trichloramine. Cyanogen chloride is a toxic compound believed to affect organs including the lungs, heart and central nervous system when inhaled. And trichloramine has been linked to acute lung injury.

In addition, a study in which disinfected swimming pool water (full of DBPs) was applied to living mammal cells resulted in DNA damage to the cells – and DNA damage may increase the risk of cancer.

While DBPs from chlorinated swimming pools have not been definitively and directly linked to cases of asthma and cancer, the possible risks may still put you on edge, especially if you’re a parent, as children’s bodies are often more susceptible to harm from various toxins.

To Swim, or Not to Swim?

Your first reaction may be to swear to never enter a swimming pool again, but that may be a bit extreme. Swimming is an excellent form of exercise, especially for those with poor joint health or even breathing conditions like asthma. It puts less stress on the body than activities like running, and the moist environment may make it easier for some people to breathe while the breathing exercises inherent in swimming may help build healthy lung function.

And, of course, in the heat of summer, kids have a blast at the pool. No parent wants to deny their child the simple pleasures of summer fun. So are the pros worth the possible risks?

What You Can Do

Given that the risks are not fully established and DBP level may vary widely from pool to pool, you may not have to give up swimming entirely. Just be smarter and healthy about it. Here are a few tips for keeping yourself – and other swimmers – a bit safer.

  • Practice good hygiene. Clean people make for a cleaner pool. Showering before entering washes away much of the dirt, oil and germs that react with chlorine to create DBPs – especially if you use soap. And be sure to shower after the pool, too. Try one of Dr. Bronner’s Magic Soaps – natural and biodegradable, you won’t take any excess reactants with you to the pool.
  • Choose pools with good practices. Are showers provided? Are people using the showers? The pool is only as clean as the people using and maintaining it.
  • Keep your head above water. Skip the dunking and diving for less water entering through your mouth, nose and eyes. Remind children not to swallow the water.
  • Make trips to the pool occasional. You don’t have to go every day. People at greatest risk for health effects are those who spend a considerable amount of time at the pool. Like anything, moderation is key.
  • Choose outdoor or sufficiently ventilated indoor pools. Good airflow means fewer DBPs are left circulating through the air you breathe.
  • Avoid pools with a very strong chlorine smell. Being able to smell the chlorine from a mile away may make you think the pool is cleaner because it has more chlorine, but too much is never a good thing. Too much chlorine in a pool not only creates more DBPs, but it may also throw off the pH balance of the water, which can lead to more problems.
  • Avoid “shocked” pools. If a pool has recently been given an extra dose of chlorine to deal with some sort of mishap like an accident in the pool, steer clear. Not only will the chlorine be too strong, but it can also take the chlorine time to kill some more resilient bacteria.
  • Swim in clear water. If it’s an outdoor pool with a lot of debris or organic matter in it, that could be providing more material for the formation of DBPs. If the water is cloudy or the walls of the pool feel slimy, go somewhere else – you could be dealing with other nasty things besides DBPs.

And most importantly,

  • DO NOT PEE IN THE POOL. It sounds obvious, but poll after poll has found that a shocking number of people have admitted to peeing in a pool – about 1 in 5. And that’s just the people who admit it! The Purdue University article reports that studies found that more than 90 percent of the uric acid (a primary culprit in the formation of DBPs) in pools comes from human pee. In addition, do not spit or – heaven forbid – poop in the pool. And if you have a little one in swim diapers, check and change them often.

Here’s a fun little ditty to help kids – and adults – stay on track with good pool hygiene.

Hope that song pops in your head every time you head to the pool!

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One Response to Health Effects of Chlorine Swimming Pools & How to Stay Healthy

  1. Cheiki August 14, 2015 at 8:16 am #

    That’s why my choice is always the beach. Safe and natural. It’s good to enjoy nature and God’s creation once in a while than to suffer with all these chemicals.

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