Pools can make you sick. Here's why — and how to stay safe.
Swimming in a pool is a great way to get a low-impact workout, stay cool during heat waves and generally boost your mood. But it’s not all floaty fun — pools come with a few risks too. Aside from drowning or choking, a number of infectious diseases can lurk in and around even the most pristine-looking pools. After a full day of splashing around, you might find yourself with an earache, upset stomach, rash or even flu-like symptoms. You wouldn’t be alone: The Centers for Disease Control and Prevention estimates that one in 44 people get a water-related illness each year.
So what is making people sick at the pool, and how can you avoid the illnesses floating in the deep (or shallow) end?
What kinds of illnesses can you get from a pool?
According to the CDC, there are a number of sicknesses linked to swimming, the most common being:
Diarrhea
Skin rashes
Swimmer’s ear
Pneumonia or flu-like illness
Eye, nose, throat and lung irritation
Why do people get upset stomachs after going to the pool?
“It’s not pool water that gets people sick, it’s the people hanging out at the pool,” Dr. Sharon Nachman, a professor of pediatric infectious diseases at Stony Brook University, tells Yahoo Life. “Pool water is not really the vehicle for transmission.” Instead, she says, it’s simply the close contact people — especially children — have at pools that leads to illness.
But being in and around water can make it that much easier for certain diarrhea-causing stomach bugs to spread, including:
Though less common, flu-like illnesses can spread between people at pools. These include:
According to the CDC, diarrhea, which can be transmitted by the so-called oral-fecal route, is the single-most-common pool-related illness. That’s why many states prohibit people who have recently had or currently have diarrhea from swimming in public facilities: They can shed particles of viruses such as norovirus or bacteria. These include E. coli, which recently made headlines when it was detected in the Seine River in Paris, where Olympians are slated to swim, which can infect others if they accidentally swallow or inhale that water or mist from the pool.
“Chlorine helps to kill germs in the water and concentrations should be maintained at an effective level” in pools, Cleveland Clinic infectious disease specialist Dr. Jessica Lum, tells Yahoo Life. “People can still be exposed to germs during the time it takes for chlorine to kill the germs.” The diarrhea-causing parasite, cryptosporidium, “is harder to kill,” Lum adds. “Even if water is disinfected or properly treated, cryptosporidium can survive for more than seven days.”
That’s one of the reasons why Nachman considers a “cloudy pool [to be] very worrisome.” If the water isn’t clear, it likely doesn’t have the correct balance of chemicals to kill pathogens.
She adds that your poolside snacks may pose as much of a risk of causing diarrhea and other stomach upset as swimming. Nachman specifically warns that leaving foods like rice, egg, tuna, chicken, potato and macaroni salads, dairy products and sandwich meats outside gives ample opportunity for staph bacteria — which can cause diarrhea, vomiting and nausea — to thrive. “Don’t leave any food sitting out and don’t take any mayonnaise-containing foods with you to the pool, that’s a recipe for disaster,” advises Nachman.
What’s the deal with swimmer’s ear?
Ear infections — including the form known as swimmer’s ear — are also commonly picked up at pools. “Swimmers ear [happens] because you’re getting water trapped in your ear,” says Nachman. “You always have bacteria on your skin” — where it’s harmless — “so that trapped water with the bacteria is what will give you swimmer’s ear,” she says. Symptoms include pain, which may worsen if the lobe is touched, itching, discharge or a feeling of ear fullness, according to Stanford Medicine.
Swimmer’s ear is more common among children and, while not all kids will get it recurrently, Nachman says that ear plugs can prevent swimmer’s ear for those who are prone to it. Swimmer’s ear can usually be treated easily with drops and a warm compress, but the Mayo Clinic advises seeing a health care provider if you have even mild symptoms, so they can be sure your eardrum or ear canal have not sustained any damage.
Why skin and eyes get irritated at the pool
Chlorine is adept at killing most germs, including some that might otherwise cause skin or eye infections. However, it can sometimes cause a rash, and even respiratory irritation, for those who are sensitive to the chemical, according to the American College of Allergy, Asthma and Immunology. Simply washing the affected area with clear water should remove the chemicals and help resolve the rash quickly.
When the chemical combines with dirt, personal hygiene products, urine, fecal matter or sweat in the pool, it can result in secondary chemicals called chloramines which in turn can trigger eye redness, skin irritation and respiratory irritation. When you detect a chlorine smell, it’s usually due to chloramines.
Tips for staying safe at the pool
It’s hard to know what germs could be in a pool or the spray around it. But taking some precautions before, after and during your fun in the sun can help, Lum says. She advises:
Do not swallow the water.
Do not go into the water if you have an open wound or cut.
Do not go swimming if you have cryptosporidium, or if you are sick with diarrhea. “People who are sick can spread the germs that are causing the diarrhea to others by contaminating the water,” Lum says. The CDC recommends waiting until at least two weeks after the diarrhea related to cryptosporidium has completely stopped before going into the water.
Shower or rinse off before going into the water to help remove dirt or particles from your body that may use up the chlorine in the water.
Change diapers away from the water to prevent contamination of the water with germs, and make sure children take bathroom breaks.
