Louise O’Connor, Contributor
Thyroid Nation

Do You Worry Your Thyroid Is At Risk When Swimming In Pools With Chlorine

It’s very tempting to take a refreshing dip on a hot summer’s day. But do you worry your thyroid is at risk when you swim in chlorinated pools? Has it ever crossed your mind? The truth is, if you swim in pools with chlorine, as most have, or take a long soak in a hot tub you are exposing yourself to potentially harmful chemicals. Unbeknownst to you, this could also possibly be negatively affecting your thyroid in the process.

You’re probably already aware of the harsh effects of chlorine. This pool chemical:

  • Makes your skin itch
  • Irritates your eyes
  • The vapors can make you wheezy
  • Could increase your risk of bladder cancer
  • And it ruins your swimsuit

Chlorine was first used to sanitize urban water supplies back in the mid 1800’s. At this time there was a major cholera outbreak, and proper sanitation helped prevent the spread of this deadly disease.

These days, chlorine-based disinfectants are routinely used to destroy potentially harmful waterborne micro-organisms such as bacteria, algae, ammonia, and germs from bodily secretions.

Firstly, Some Basic Chlorine Facts.

Chlorine is popular because it handles the three main jobs in keeping a swimming pool clean: It sanitizes (kills bacteria and germs), oxidizes (controls organic debris from perspiration and body oils), and deters algae.

Chlorine is an element that is classed as a halogen. Fluorine, bromine, iodine, and astatine are also halogens. They are grouped together as they are chemically related. You may remember studying the periodic table of the elements at school. Halogens can be found together on row 17 of the periodic table.

Iodine is part of this group but there’s an important point of difference. Iodine is crucial to health. Chlorine, fluorine, bromine, and astatine have similar structures to iodine and use the same receptors in the body. The problem is, once absorbed these antagonistic elements block iodine.

Of all the minerals that support proper thyroid function, iodine is the most important. Iodine is an essential component of your thyroid hormones triiodothyronine (T3) and thyroxine (T4).

Aside from its vital role in thyroid health, iodine is also necessary to support proper immune system function, breast and prostate health, and normal growth and development during pregnancy.

When you take a dip in a chlorinated pool, or hot tub you risk absorbing an excessive amount of chlorine through your skin. This has the potential to block iodine activity at a basic cellular level.


Are Chlorine Compounds A Danger To Your Thyroid Health?

Aside from the adverse effects of chlorine, a recent study published in Environmental Science and Technology reveals common disinfectant techniques can lead to the formation of by-products that are far more dangerous. 1 Termed disinfection by-products (DBPs), these are formed when chlorine, or other disinfectants react with compounds that swimmers add to the water such as sweat, urine, and pharmaceuticals. DBPs are also formed when chlorine mixes with ingredients derived from personal care products such as sunscreens, body lotions, make-up, perfume, etc.

This recent study from the University of South Carolina is ground breaking as it’s the first study to demonstrate that water disinfectants can increase our exposure to a wide range of harmful DBPs. The researchers took 28 water samples from seven sites, and their analysis revealed water samples harboured more than 100 DBPs, including a new class called bromoimidazoles. Furthermore, the researchers found that the higher use facilities had much higher concentrations of DBPs.

The US Environmental Protection Agency (EPA) warn DBPs can accumulate in pool water, and pose a potential threat to long term health. DBPs are linked to DNA damage, which may increase cancer risk. 2,3


A new study published in the journal Pediatrics found that children who spend a lot of time at indoor swimming pools during their early years are more prone to developing asthma, recurrent bronchitis, and other breathing problems as they grow older, compared to others who do not frequent indoor pools. ~ Dr. Mercola

Could chlorine and chlorine by-products pose a serious threat to your thyroid health?

To date there are no specific studies to demonstrate water sanitizers could have an adverse effect on the thyroid. However it is widely accepted environmental toxins pose a serious threat to thyroid health, especially if you have a family history of thyroid disease. The hazardous by-products that you are exposed to when swimming, or soaking in a hot tub could easily enter your bloodstream, and eventually infiltrate your thyroid via general circulation.


Are Saltwater Pools Any Better?

If you are worried your thyroid is at risk when using a chlorinated pool you may be wondering if it’s safer to swim in a saltwater pool. There’s a common misconception that saltwater pools do not use chlorine, and are therefore a safer alternative. However saltwater pools are not actually chlorine-free. Salt chlorinators are used in salt water pools to convert common salt crystals into chlorine gas which then rapidly dissolves into the water. This means saltwater pools could carry similar risks to chlorinated pools. (But are definitely a safer, better option)

How Can You Safeguard Your Thyroid This Summer?

To help heal your thyroid it’s best to avoid bathing in swimming pools, and hot tubs. There are three main reasons why and what you might can do, if you decide to take an occasional dip:


You will minimize your exposure to chlorine, and dangerous chlorine by-products. The research is clear, disinfection techniques create compounds that pose a serious risk to long term health. There could also be a real risk to your thyroid health.


You will reduce your risk of picking up some type of waterborne infection. No system is fool-proof. Disease transmission can still occur even when a swimming pool, or hot tub is properly treated. Toddler pools carry the biggest risk as you are swimming with infants who are not yet toilet trained.


Try showering before and after, if you are going to occasionally partake in wading or floating around in swimming pools. Here’s why:

Julie Deardorff explains in her article published in the Chicago Tribute, “Another important reason to shower is that our bodies generally contain residue from consumer products, including perfume, make-up, body lotion, shampoo and sunscreen.

When the chemicals used to disinfect the pool mix with organic matter (sweat, hair, urine) or nitrogen-rich substances (commonly found in consumer products) it can create a more toxic agent, said Michael Plewa, a professor of genetics at the University of Illinois whose new research has linked pool chemicals to health problems, including asthma and bladder cancer.

Louise-Diet-Book-Thyroid-Nation-Ad3In Summary

I stopped swimming in chlorinated pools many years ago. I noticed swimming in pools left me feeling weak, and unwell. After researching information for this post I am even more convinced chlorinated pools, and hot tubs are not a healthy option. I am actually amazed chlorine-based disinfectants are still routinely used given the research that has emerged in recent years.

A healthier option? Enjoy a refreshing swim in the ocean, or a clean river, stream, or lake. This has the added bonus of reconnecting you with nature. It’s great for improving your feelings of wellbeing and definitely better for your thyroid.

Stay up-to-date, get tips, articles and stories that inspire, on all things thyroid!

About the Author

Louise O’Connor is a leading Australian Naturopath + Wellness Coach who graduated from the Endeavour College of Natural Health, Brisbane Australia in 1995. She is a registered Naturopath with the Australian Traditional Medicine Society (ATMS), the peak association of natural medicine practitioners in Australia. She educates and writes on thyroid health. Louise embraces a holistic approach to thyroid health and advocates seeking out and treating the underlying causes, rather than just addressing the symptoms. Louise is the author of the top selling e-Book: The Natural Thyroid Diet. The 4-Week Plan To Living Well, Living Vibrantly. Be sure to Follow her on Facebook and Twitter.

PLEASE take a moment to ‘Like’ us on Facebook and follow us on Twitter and Pinterest. You can also listen to Tiffany and Danna on Thyroid Nation RADIO.

Questions or anything to add about chlorine and your thyroid? We want your thoughts, please. You might just help someone else in need.