Chlorine is a chemical added to swimming pools to kill harmful bacteria, according to the Centers for Disease Control and Prevention (CDC).
While chlorine helps protect you from infections, it can have some unexpected effects on your body. “As the concentration of chlorine increases, the chances of you developing a reaction such as itchiness or red eyes, or even experiencing a strong chlorine smell, increase,” says
Vivek Cherian, MD, a Chicago-based internal medicine physician.
The CDC recommends a chlorine concentration of at least 1 part per million (ppm) in swimming pools and 3 ppm in hot tubs — which you can test using a N,N diethyl-1,4 phenylenediamine sulfate (DPD) kit — but the agency doesn’t specify what concentration is too high.
Should you be worried? What’s more, how can you fix or avoid chlorine’s effects so you can enjoy your time in the pool?
1. Chlorine Can Leave Skin Feeling Dry
After you exit a pool and towel off, you may notice that your skin feels dry and itchy, especially if you swim frequently or for extended periods.
“Chlorine is a skin irritant that strips the skin of its natural oils,” says Samer Jaber, MD, a board-certified dermatologist and the founder of Washington Square Dermatology in New York City. By removing natural oils, chlorine erodes your skin’s natural protective barrier, he says. Without this barrier, your pores open, making your skin more vulnerable to water and chlorine.
The potential result? Dry, scaly, and itchy skin.
What to Do About It
The longer chlorine remains on the skin, the more irritating it becomes, so shower as soon as you’re done swimming.
“Use a gentle body wash and don’t exfoliate, as this will irritate your skin,” Dr. Jaber says. Apply a thick, moisturizing cream immediately after stepping out of the shower to help rebuild your skin barrier — it’s most effective when your skin is still damp.
2. Chlorine Can Lighten and Dry Out Hair
In addition to killing bacteria in swimming pools, chlorine is used as a bleach in the manufacture of paper and cloth, according to the CDC. Its bleaching effect can damage your hair.
“Chlorine strips off the natural oils in the hair, which can result in dryness, changes in hair color, and even an itchy, irritated scalp,” Dr. Cherian says.
Many people blame chlorine for the green-hair phenomenon. While light-colored locks can look green after being in a chlorinated pool, the culprit isn’t chlorine — it’s oxidized copper. People sometimes add copper sulfate to pools to prevent the growth of algae. People with previously damaged hair are most likely to see these greenish effects.
What to Do About It
Thoroughly rinse your hair with nonchlorinated water before getting in a pool, says Cherian: “The idea is that your hair is already saturated with clean water, so it will absorb less chlorinated water.”
Once you’re done swimming, head for the shower and wash your hair with a clarifying shampoo to remove chemicals.
These deep-cleaning shampoos typically contain a strong detergent like lauryl sulfates as their primary ingredient.
(If your hair is prone to a greenish tint, you might want to look for a shampoo that’s specifically formulated to remove copper from hair.) Follow with conditioner to add moisture to your hair and help restore the skin barrier in your scalp, Jaber says.
Yet the easiest way to prevent chlorine damage is not to get it wet in the first place, says the Hair Professionals Career College.
So get a swim cap. If you’re
swimming for exercise, a swim cap will keep hair out of your face so you can focus on your workout and protect your hair from chlorinated water.
3. Chlorine Can Leave Eyes Red and Irritated
Red, sensitive eyes are another hallmark of chlorinated pools.
When chlorine gets in your eyes, it washes away the tear film that coats the surface of your eyes and keeps them moist, smooth, and clear. Without a tear film, your eyes are more vulnerable to chlorine’s irritating effects.
“Chlorine may cause irritation that can result in teariness, redness, and sensitivity to light for a few hours after leaving the pool,” Cherian says.
Plus, your eyes may be more susceptible to infection if any pool bacteria survive the chlorine, Cherian says. For example,
pink eye (conjunctivitis) can be transmitted between people via swimming pool water.
What to Do About It
First, don’t wear contact lenses in a chlorinated pool, Cherian says. Bacteria can grow on the lenses after a single dip, and because contact lenses sit on your eyes for a longer period, your eyes are continuously exposed to any chemicals or bacteria on them.
Wearing swim goggles can keep pool chemicals out of your eyes, helping your tear film stay intact. You may even be able to get prescription swim goggles, according to the American Academy of Ophthalmology (AAO) — ask your eye doctor.
If you prefer to swim goggle-free, splash your closed eyes with fresh water immediately after swimming to wash chlorine off your eyelids and eyelashes.
Finally, the University of Utah recommends using over-the-counter lubricating eye drops before and after swimming to keep your tear film balanced.
4. Chloramines Can Trigger Respiratory Issues
When chlorine mixes with swimmers’ sweat, dirt, and skin cells, it creates the chemical irritants known as chloramines. Chloramines in the water then convert to gas in the surrounding air, which can cause respiratory symptoms such as coughing and
wheezing when inhaled, according to the CDC.
People with asthma may feel the effects the most, as their airways are hypersensitive to irritants. Inhaling chloramines can cause the lungs to spasm, leading to chest tightness or coughing, Cherian says.
“This can be an issue in any pool, but it tends to be more problematic in indoor pools that are not well ventilated,” he says. “In outdoor pools, [chloramines] tend to dissipate quickly.”
What to Do About It
This isn’t to say that people with asthma can’t — or shouldn’t — swim in chlorinated pools. But you’ll want to avoid or limit the time you spend in a pool with a strong chlorine odor.
According to the CDC, that smell suggests there are chloramines in the air. If swimming is your primary or preferred form of exercise, work with your pulmonologist to tweak your
asthma medication if needed. It’s also a good idea to keep your reliever inhaler poolside.
5. Chlorine Can Sometimes Worsen Skin Conditions
Because chlorine strips away the natural oils in your skin that act as a protective barrier, spending time in a chlorinated pool can lead to a flare-up or worsening of psoriasis and eczema (sometimes referred to as atopic dermatitis, the main type of eczema), Jaber says. However, the effects vary from person to person.
In fact, swimming in a chlorinated pool may benefit some people with eczema. Chlorine is a bleach, and bleach baths may reduce eczema symptoms by killing bacteria on the skin, reducing itching, redness, and scaling.
Many people with eczema find that swimming in a chlorinated pool has a similar soothing effect, but some people managing eczema find that chlorinated pools irritate their skin.
Similarly, some
people with psoriasis may handle chlorine just fine. However, others are more sensitive to the drying effects.
People with acne may also benefit from chlorine. “Chlorine has antibacterial properties, so it can actually kill the bacteria that causes acne,” Jaber says.
However, if chlorine dries out the skin, it can make acne worse, he adds. According to the American Academy of Dermatology Association, dry skin is irritated skin, and anytime you irritate your skin, acne can become more severe.
What to Do About It
If you’re among those people with eczema who find chlorinated pools irritating, you may want to stick to swimming in fresh water.
The same goes if you have psoriasis, especially if you have infected plaques.
You may find that swimming in salt water offers some symptom relief, according to the National Psoriasis Foundation, though you should take care to keep your skin moisturized after a dip.
Avoid swimming if your skin is infected or you have sores or open wounds.
If you decide to swim in a chlorinated pool, rinse with lukewarm water beforehand. Then shower with a gentle skin cleanser as soon as you get out of the pool and apply a thick, cream-based moisturizer, Jaber suggests.
If your acne worsens due to chlorine, Jaber recommends washing your skin with a mild cleanser after swimming. Use a nonabrasive cleanser that doesn’t contain alcohol or oil. Be sure to restore your skin barrier with a gentle moisturizer. Look for products that are labeled “oil-free” and “noncomedogenic.”
Chlorine Sensitivity: What It Is and What to Do About It
If your skin, eyes, or lungs react to chlorine in swimming pools, you may wonder if you’re allergic. You can’t be allergic to chlorine, but you can be sensitive or have a nonallergic reaction to it.
For example, chlorine can contribute to allergies by irritating the respiratory tract or sensitive skin.
Per the American College of Allergy, Asthma & Immunology, common symptoms of chlorine sensitivity include the following:
- Coughing
- Trouble breathing
- Runny nose
- Stuffy nose
- Skin redness, tenderness, inflammation, or itchiness
- Skin lesions or rash
- Scales or crust on the skin
These symptoms tend to be most common among people with long-term exposure to chlorine (more than 1,000 hours) and those who swim in pools with high chlorine levels.
See an allergist if you think you have a chlorine sensitivity. They can help you control existing allergies or conditions, which may reduce the effects of chlorine.
Rachel Green
Rachel Davis
Derek Schulz
Sophia Martinez
Dr. Amara Okafor