In fact, swimming is one of the healthiest exercises in existence because it not only carries very little risk of serious injury (unless you foolishly dive into the 1ft deep shallow end), but also works many of your muscles simultaneously. Swimming relentlessly in a pool for half an hour provides one of the best muscle pumps you can get without visiting a full-blown gym.
However, there’s a problem: the chlorine. You’ll surely know of the stinging eyes and thinning hair from spending an hour in a swimming pool. Countless acne patients complain of dry, flaky skin. On the other hand, there’s a vast swathe of acne patients who believe that regularly swimming in chlorinated pools improves their acne.
The reality is that a dodgy diet is by far the biggest cause of acne (that food has zero effect is a colossal myth), but could chlorine exposure still be an excellent bonus strategy?
The acne community is massively divided, and hence, today we will discuss all the science surrounding chlorine and its chemical by-products and their effect on human skin.
Chlorine – an expert at drying your skin
Firstly, the whole purpose of chlorine in the United States and in nearly every developed country on earth is to kill harmful bacteria and algae. Without some disinfectant a swimming pool will become inundated with organic matter and pathogenic bacterial strains such as Shigella, e.coli, giardia, and many more, with Recreational Waterborne Diseases being the consequence.
The chlorine is diluted, but in pure form it is toxic and hence kills microorganisms such as bacteria effectively. Chlorine is used in both public swimming pools and waterparks for that reason, and since the early 20th century in US public water supplies (tap water, shower water).
It is that antibacterial power of chlorine which makes many acne patients identify it as a prospective acne cure. Their somewhat logical goal is to bathe their face in chlorine and kill the p.acnes bacteria dwelling in their pores. Don’t get tempted into it!
Undoubtedly, some people did experience the improvement in acne from swimming, but consider these factors. Most people swim in an outdoor pool most frequently in summertime, where they are exposed to more sunlight which increases both vitamin D (a seriously powerful nutrient for acne) and the generation in your skin of nitric oxide, an anti-inflammatory gas. Furthermore, swimming itself provides excellent exercise.
Finally, many people swim daily while on a relaxing holiday, a holiday where their stress levels are often substantially lower, and often a holiday spent away from their usual city environment with air pollution, unhealthy food, even more stress from long commutes and so on.
If you believe that chlorine in swimming pools has improved your acne then it was probably something else. Furthermore, chlorine has strong drying powers which should not be dabbled with lightly.
Recently I conducted a fascinating experiment with chlorine. Last week I returned from a holiday in Florida where every single day I was either swimming in a chlorinated pool or visiting a waterpark. I examined my skin every day for the purpose of experimentation.
Here’s what I noticed…
ONE – immediately after leaving the chlorinated water my skin would feel all rubbery and smooth, almost like the skin of an aquatic mammal such as a dolphin, like I had no hair. This effect would persist after having a shower. Initially my acne was not worse.
TWO – a few hours later my skin would be extremely dry and flaky. My skin never usually gets flaky.
THREE – by the next day my skin was still dry and many tiny pimples were beginning to appear, creating a very poor skin tone overall.
That exact story has been replicated hundreds of times on the internet; drying and flakiness is a common theme.
Why does it happen?
The toxic properties of chlorine can damage proteins on the surface of your skin. Over the course of hours, the cells then die and leave you with a non-hydrated layer of flaky dead skin.
Chlorine has also been confirmed by science to mess with human skin barrier function. The human skin barrier is essentially your skin’s natural defence system, featuring an acidic PH which destroys many of the infectious viruses and bacteria attempting to enter your body, much like the earth’s atmosphere burning up an entering comet. The skin barrier also maintains your skin’s hydration and adjusts the water content in tune with weather conditions like air temperature and humidity.
This study from 2003 analysed patients with atopic dermatitis and exposed their skin to chlorine through bathing water. Chlorine directly decreased the water-holding capacity of the skin, or in other words, the skin became drier.
The loss was dose dependent as well; the higher the chlorine content of the water the greater the drying effect.
The study also found that patients with atopic dermatitis (an inflammatory skin condition similar to acne) were more vulnerable to the drying effect from chlorine. Additionally, the chlorine was only applied for a maximum of ten minutes; after 40 minutes in a pool or 5-6 hours at a waterpark the drying will be massively magnified.
This study confirms the skin-drying properties of chlorine observed first hand by so many acne patients. The results are extremely interesting because the concentration of chlorine in the bathing water was nearly equal to that of public swimming pools.
Many acne patients would be delighted to hear that news, but dry skin is not the godsend it seems. Lack of skin hydration encourages your sebaceous glands to increase their sebum production in the medium term, since hydration is important for skin barrier function.
More sebum increases rather than decreases the risk of blocked pores and acne, so if you read about topical chlorine application to dry out the skin, ignore it!
It doesn’t end there. Chlorine has several other interesting powers. Apparently chlorine can penetrate the proteins in your hair shafts and change their colour. Many blonde people have been shocked to observe their hair changing from blonde to green after a day in the pool. Chlorine can even react with topical acne treatments to produce burning and inflammation. Many professional swimmers apply specialised barrier lotions to minimise these side effects.
Can chlorine cause acne from the inside-out?
Chlorine can also permeate the skin and directly enter the bloodstream and once inside damage your health. Chlorine is a hazardous chemical that is strong enough to kill microorganisms such as bacteria when diluted. A human body is more resilient than minuscule bacteria but it is still vulnerable.
For instance, there’s evidence that high exposure to chlorine in swimming pools increases the risk of stillbirths and even spontaneous abortion in pregnant women, and congenital malformations in the foetus. A 2007 study found that participants who ingested chlorine through drinking water had a 35% greater risk of bladder cancer compared to those who didn’t, while those who regularly swam in chlorinated pools had a 57% greater risk.
As for acne related problems, one unproven, but dangerous theory is whether the antibacterial powers of chlorine in a swimming pool could affect your all-important gut flora.
All acne patients need a healthy diversity of good bacterial strains in their gut to protect against inflammation from unhealthy bacteria, to prevent leaky gut syndrome, and to increase nutrient absorption. It’s possible that ingesting chlorine unwittingly while swimming, breathing in chlorine vapours, and absorbing chlorine through the skin could decimate these bacterial colonies, and allow unhealthy yeasts like candida to multiply.
It’s also possible that the chlorine is diluted before it reaches the bacteria, but nevertheless, a substance used worldwide for killing microorganisms is not something you want near your gut. There’s also many studies showing that chlorine can increase inflammation levels in the body, inflammation which later shows itself on your face.
Contrary to popular belief, studies have shown that while swimming in chlorinated water you absorb even more chlorine than drinking the water.
Studies at the University of Pittsburgh have concluded that we absorb more chlorine from wearing clothes washed with it and showering in chlorinated water compared to drinking the chlorine. One study found that on average, absorption through the skin was responsible for 64 percent of total exposure to waterborne contaminants such as chlorine.
Another study found that while spending ten minutes in a chlorinated shower, you absorbed the equivalent of 8 glasses of water, and all the chlorine with it. Human skin has natural barriers against toxins but chlorine is small enough to fit through. Any molecule with a molecular weight below 3000 can enter human skin, below 750 can enter skin cells, and below 150 can enter into bloodstream. Chlorine has a molecular weight is 35.4.
In fact there’s a widely reported test with your finger that shows just how efficiently chlorine gets absorbed.
Visit a swimming pool supply store and purchase a chlorine test kit. Fill a glass with some chlorinated water, whether tap water or from a swimming pool. Test it with the kit and the water will change colour to demonstrate the chlorine level of the water. If you then stick your finger in the water for 60 seconds, wiggle it about, then test the water again, the colour will be completely different; it will demonstrate a chlorine content of virtually nothing.
Another problem is that so many of us are deficient in the nutrient iodine; chlorine is a halide that is structurally similar, and with an iodine deficiency your body will relentless try to suck chlorine in through the skin.
So if you’re swimming around in a pool, compared with a shower where you aren’t completely submerged, the absorption will likely be much greater. It can enter your bloodstream directly where its inflammation causing powers aren’t deactivated through digestion in the gut.
Chlorine produces many dangerous by-products
Easily the least famous hazard of chlorine is all the Disinfection By-Products (DBPs) it creates when added to a pool. DBPs are formed when chlorine reacts with organic matter like sweat, dirt, and so on. Many public pools are teeming with these DBPs; there are hundreds of different types that can form depending on the specific organic matter the chlorine reacts with.
One example is cyanogen chloride, which is most commonly used as a chemical warfare agent. One study found that 20% of Americans admit to peeing pools regularly. CNCI is formed when uric acid from urine reacts with chlorine. Disturbingly, it is found in nearly every chlorinated pool.
CNCI is a known toxicant to the lungs and heart. At higher levels it can cause convulsions, coma and death. Fortunately, the levels required for outright death are nearly impossible to reach. If the pool you were swimming in had enough chlorine to generate those levels of CNCI then you’d be a skeleton by the time you climbed out of it.
However, like other chemicals such as BPA, there are likely insidious consequences like inflammation at the lower, apparently safe levels. Another class of DHPs are trihalomethanes (THMs), which can be found in higher concentrations in swimming pools than unfiltered tap water. THMs float above the water and can be breathed in as you swim.
Major consequences of THMs at higher levels include reproductive problems in animals and humans such as spontaneous abortions, stillbirths and congenital malformations. Trihalomethanes are also a group B carcinogen, meaning that they have been demonstrated to cause cancer in limited animal experiments.
Then there’s haloacetic acids, or HAAs, demonstrated by Spanish scientists to be present in the urine of swimmers just 30 minutes after they left the swimming pool. HAAs are restricted in water supplies due to their link with cancer and birth defects. 49 participants, both adults and children, were found to contain HAAs for up to 3 hours after a trip to the pool.
Not every participant even entered the pool; some worked by the pool and still ingested HAAs. They were deemed to have inhaled the chemical in vapour. Those who swam had levels four times higher than those who worked there. The children had significantly higher HAA levels after swimming (the skin of children has a higher absorption capacity).
Do any of these chemicals cause acne? There’s too many to analyse them all, but CNCI is linked to chronic inflammation, the single biggest cause of acne. HAAs also cause inflammation and THMs may deplete the all-important antioxidant glutathione.
What’s interesting is that because these DBPs are formed solely from chlorine reacting with organic matter, every single swimming pool on earth could have a unique profile of them. One pool may have excessive CDCD, another could be full of THMs. This could explain why some people noticed dryness and burning and acne from chlorinated pools whereas others notice nothing.
Number one is obvious – if you live by the coast, swim in the sea instead. As long as the water isn’t polluted (or full of sharks) it could benefit your skin as salt water contains many natural minerals. Some people have a sensitivity to salt water, and this manifests itself as burning and irritation. However, this is uncommon.
Another option is swimming in a local lake, if you live in a rural area, and especially a pristine alpine lake free from pollution and full of minerals. If you live near the Dead Sea of the Middle East, then you have goldmine sitting on your doorstep. The Dead Sea is extremely rich in minerals and people suffering from skin problems flock from all over the world to bathe in its waters.
Secondly, you should get your iodine levels in check. Why? As we discussed earlier, iodine and chlorine are structurally similar. Actually, they are both halides. That’s a group of four natural elements; chlorine, fluoride, bromine, and iodine, which is the only one that is an essential nutrient (needed for thyroid function). The other three are toxic and not necessary.
The problem is that they are lighter than iodine and easily displace it in the cells. They are just as easily as absorbed as iodine too. The evidence suggests that if your iodine levels are low, chlorine absorption is far greater because it mistakes the structure for iodine.
Therefore, follow the dietary instructions in this article like eating eggs, seaweed, strawberries, fish, and so on. Alternatively, you could a highly potent iodine supplement (careful not to apply too much) such as TPCS Iosol Formula.
Next, make sure you shower immediately after swimming, to remove at least some of the residue. If you have your own pool then some might recommend a saline salt pool, but they function by generating chlorine themselves. They simply add salt to the water and use a chlorine generator to create chlorine from the salt through electrolysis. There are also chemical alternatives to chlorine available, but they are a joke because they’re often more dangerous than chlorine themselves.
Many studies from the 1950s and 60s tested iodine as a disinfectant for pools. This study found that iodine was just as effective as chlorine, if not more so, and caused far less stinging and health consequences. However unless you’re extremely rich, the hassle of devising an iodine based system would not be worth the small advantage for your skin, especially if you only swim rarely.
Is chlorine exposure a disaster? No, but it’s highly likely to worsen your acne somewhat and if that’s what you’ve noticed, your observation was correct.
Despite all the problems with swimming outlined above, I will never consider giving up swimming in chlorinated pools and I’ll definitely keep visiting waterparks. If clear skin means you have sit in a room all day staring at the wall then there’s no point of having it.
The same old theme applies; if you relentless focus on keeping your lifestyle acne-friendly most of the time, indulging occasionally will not harm your skin at all. It’s the same with eating a healthy diet nearly every day and eating a pizza once a fortnight. Additionally, there is evidence that the damage from DBPs is only temporary; the study above found that haloacetic acids were fully excreted from the body after just 3 hours.
So remember this information if you suddenly get acne after a day at a waterpark, and are frantically trying to identify the culprit. If you have the ocean nearby, swim there instead for an acne-friendly option.
Thanks for reading!