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In case you need a reason: Science says don’t pee in the pool

Kids do it. Olympic swimmers do it. I bet you’ve done it, too. But one scientific study insists peeing in the pool isn’t just gross — it’s dangerous.

Ryan Lochte and Michael Phelps famously came out after the 2012 Summer Olympics, admitting everyone pees in the pool sometimes. “Chlorine kills it so it’s not bad,” claims Phelps, the 18-time Olympic gold medalist.

Not so fast, Michael.

While chlorine does disinfect the pool, clearing out bacteria, it doesn’t do a thing about the uric acid present in the urine. In fact, a study published in Environmental Science & Technology by Purdue University chemical engineer Ernest Blatchley and colleagues posits the reaction between uric acid and chlorine is precisely the problem. “There’s this perception that peeing in a pool is okay because there’s chlorine,” Blatchley explains. “That’s just not true.”

In their study, the scientists found uric acid — also present in sweat, though over 90 percent of what is found in the pool comes from pee — and chlorine reacted to form two compounds, cyanogen chloride (CNCl) and trichloramine (NCl?). While the internet hyperbole machine was quick to label these compounds as “chemical warfare,” the reality in a typical neighborhood swimming pool is far less terrifying — though not without concern, particularly in public indoor pools. Cyanogen chloride and trichloramine can affect air quality and cause breathing problems, particularly in those with compromised respiratory systems or asthma.

As with everything in scientific reporting, take the presentation of data with a grain of salt. It’s the dose that will hurt you, not the compounds themselves, and the levels present in a typical swimming pool still fall well below the World Health Organization’s safe maximum concentration. But for adults and children with asthma or other respiratory problems and those who work at public pools, this information could be a missing piece of the puzzle, helping them understand why their symptoms may worsen the more time they spend in the water and ensuring they take necessary precautions.

In short, don’t let this information scare you off visiting the pool, but maybe let it serve as a reminder not to use the thing as a toilet. Because bottom line: Peeing in the pool is pretty gross, even if it’s not lethal chemical warfare.

“Given that uric acid introduction to pools is attributable to urination, a voluntary action for most swimmers,” the study concludes, “these findings indicate important benefits to pool water and air chemistry that could result from improved hygiene habits on the part of swimmers.” Think of it like any other hygienic practice. Skipping dental floss and deodorant isn’t going to kill you, but it’s not going to make you any friends, either. Maybe let’s just all agree to go where we’re supposed to from now on.

Peeing in the ocean is still fair game, though.

More on pools

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Keep your tech safe: Avoid a poolside disaster this summer
Glass-bottom pools that will absolutely terrify you

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