Urine causes red eyes after swimming, CDC says

Chuck Bednar for redOrbit.com – @BednarChuck

Now that summer is officially underway, folks are flocking in droves to the neighborhood pools, but before putting on that bikini and diving into the deep end, you might you might want to know the real reason swimming can give you red, stinging eyes and a runny nose.

Hint: It’s not the chorine’s fault, according to the CDC’s annual healthy swimming report.

Those symptoms, as well as the strong chemical smell usually blamed on the substance used to keep pools clean and free of bacteria is actually caused by chemicals that form when chlorine mixes with urine, feces, sweat, or dirt from the bodies of other swimmers, the report said.

Pools, waterparks, hot tubs, splash pads, and similar facilities that have not been contaminated with pee, poop, or filth will not have that odor, the agency noted. In fact, Michele Hlavsa, head of the CDC’s healthy swimming program, told NBC News that the stronger smell that a pool has, the higher the content of urine or other contaminants.

News flash: Chlorine will not kill germs from pee, poop

“When we go swimming and we complain that our eyes are red, it’s because swimmers have peed in the water,” explained Hlavsa. “The nitrogen in the urine combines with the chlorine and it forms what’s known as chloramine and it’s actually chloramine that causes the red eyes.”

One common misconception, she told NBC, is that chlorine can clean the urine out of the pool, and that it’s really no big deal if someone pees in the water just a little bit. In fact, she said that chlorine can barely keep E. coli and other natural bacteria at bay, and becomes overwhelmed if people start adding their own sweat, dirt, or bodily wastes into the equation.

Pool owners are urged to purchase a pool tester to gauge the water quality. “You can get them at big box stores, pool supply stores, and hardware stores,” Hlavsa said. They can be used to measure both chlorine level and the pH, which measures the chlorine’s effectiveness, she added. The chlorine level should be between 1 and 3 ppm, while the idea pH is between 7.2 and 7.8.

The CDC also provided a handful of suggestions that swimmers can use to help keep the pools they visit clean, such as showering for one minute before entering the water, taking a bathroom break every hour, and keep in mind that swim diapers are not leak-proof. Avoid urinating or defecating in the pool, and just don’t swim if you’ve got the runs.


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