The Long Term Effects of Chlorine on Swimmers

Long Term Effects of Chlorine on Swimmers

Some alarming results from studies conducted in recent years have people concerned about chemical by-products and other waste products affecting their health. In one study, the presence of micro-plastics was found in human blood, and in another study, it was found that out of 212 chemicals the CDC tested for in Americans (44 of which were pesticides), they found most of them.

This is cause for concern; what exactly are we putting into our bodies? What is in the food we eat and the water we drink? Chemicals, even in tiny doses, can negatively affect our development, health, and reproduction. There needs to be more awareness of the dangers of overexposure to chemicals and waste products.

As a swimmer, surely you have wondered what are long-term effects of exposure to chlorine? Pools are treated with a slew of chemicals to keep it sanitary, the most prominent of which is chlorine. Chlorine is the same chemical used to treat drinking water by eliminating microorganisms in it. When chlorine reacts with the pathogens inside water, toxic compounds called disinfection byproducts (DBPs) are formed.

While overexposure to chlorine has some negative effects, many of the negative side effects we attribute to chlorine are actually caused by disinfection byproducts. DBPs can enter the human body via drinking the water, inhaling it in gas form, or absorbing it through our skin while swimming. This can lead to long-term effects like increased risk of cancer, reproductive problems, asthma, respiratory issues, skin wrinkles, and dried out skin and hair.

Keep reading on to learn about each side effect in more detail.

Possible long-term effects of chlorine on swimmers

It should be noted that many of the studies that came to these conclusions either had a small sample size or conducted their tests on animals such as rats. There is also anecdotal evidence that these effects can occur. Overall, it is still inconclusive exactly how much of an effect chlorine and its DBPs has on the long term health of humans.

Chlorine cough

Most swimmers have developed a “chlorine cough” which is a nasty dry cough that is not only irritating, but a legitimate health hazard.

The causes of chlorine cough are due to poor ventilation at the pool and overexposure to chloramine, a DBP formed when chlorine mixes with urine, sweat, and the natural oils on your body. Chloramine is also responsible for that “pool smell” that all pools have.

There’s not much you can do about this except pray that your pool improves their ventilation, swimming outdoors where harmful gases can dissipate into the air, or simply swimming less.

Unfortunately, the impact of chlorine coughs are exacerbated if you have asthma which an alarming amount of swimmers do.


In a similar vein, overexposure to chloramines can also lead to asthma. It is estimated that approximately 25% of all competitive swimmers are suffering from asthma. That’s too many to simply be a coincidence.

Looking into it, a study found that chlorine and its DBPs can hover above the air at the pool’s surface when they evaporate into gases, and this is right where swimmers are inhaling “fresh” oxygen. I mentioned coughing as a side effect, but swimmers also frequently sneeze and struggle to breathe. Over time, asthma is developed. It is clear that the DBPs are wreaking havoc on one’s respiratory system.

Many people reading this right now either know a swimmer who is suffering from asthma, or is that swimmer. Thankfully, asthma is very treatable, and swimmers can continue swimming with minor effects as long as they keep their inhaler close by.

Speaking anecdotally, it seems that many swimmers with asthma developed it as a result of swimming because they claim not to have asthma before. Thankfully, it seems to not have much of a long-term effect because as soon as they quit swimming, they no longer suffered from asthma and did not need medications or inhalers anymore.

Dry skin and hair

It seems no amount of moisturizer can keep a swimmer’s skin healthy and hydrated. It is the price to pay if you want this sport to be part of your life. What is it about pool water that makes it have such a dehydrating effect?

Essentially, your skin and hair are normally protected by a protective layer of an oily and waxy substance called sebum, often colloquially referred to as “the natural oil that the body produces.” Chlorine removes the sebum from your skin and hair, leaving them high and dry, literally.

With your natural oils constantly getting stripped off, without any intervention on your part to apply hair oils or moisturizer, your skin will flake, itch, sting, burn, and crack.

Again, none of this is permanent. If you limit the time and frequency you spend at the pool and take care of your skin and hair with moisturizing products, you can limit the damage and eventually fully heal from it.


The CDC has not classified chlorine as a carcinogenic chemical, however some of the chlorination by-products, specifically trihalomethanes (THMs), might be classified as such.

There have been claims over the years, some with studies backing them, that ingesting water treated by chlorine can cause cancer. Well guess what, unless you’re collecting your own freshwater, you’re drinking, showering, and swimming in water that has been treated with chlorine.

None of these claims have been definitively proven, so don’t freak out, swear off swimming, and quit your swim team just yet. Specifically, what was discovered was that there was an increase in markers associated with cancer, but not a rise in cancer itself.

As a swimmer, obviously you are not literally ingesting the pool water that you’re swimming in, though that can happen occasionally by accident. That said, these chemicals can still get absorbed into your body through your skin or inhaled through the air, so you are being exposed to it plentifully.

At this point, it’s still too early to say whether the results of these studies are false-positives or not. Chlorine seems to have a link to increased risk of bladder, rectal, and breast cancers, but ultimately more research needs to be done.

Wrapping up

Chlorine is an essential chemical used to disinfect water, whether that’s water we drink, shower in, or swim in. There is no question that it has provided us with many benefits. Without it, large swimming pools would be unsafe to swim in long-term.

At the same time, we are now starting to understand some of its darker qualities – that it is like a poison to our bodies when exposed to it for long periods of time, resulting in respiratory issues, dry skin, acne, and possibly even cancer.

Even with this knowledge in mind, unfortunately there’s not much you can do about it since society has become so reliant on chlorine to provide access to clean drinking water. If you’re willing to make the effort, you can try installing a carbon-based filter that absorbs chlorine from the water.

You can also consider switching to a saltwater pool which uses less chlorine and can maybe help you avoid many of chlorine’s side effects (though saltwater pools have their own problems).

If you have the funds, you can consider building an all-natural, eco-friendly swimming pool, though this is an extremely expensive option.