CHLORINE IN THE POOL DOESN'T MAKE YOUR EYES RED -- IT'S THE URINE (Shutterstock) Do you think you know why your eyes turn red after a day of swimming? The answer is grosser than you think and might make you think twice about heading to the pool this summer. For their annual Healthy Swimming Program, the Centers for Disease Control (CDC) teamed with Water Quality and the Health Council and the National Swimming Pool Foundation to educate Americans about the dangers of pools and how to stay healthy when swimming, according to Women's Health. "We think that swimming is a really fantastic activity," said Michael J. Beach, Ph.D., associate director of the CDC's Healthy Water program. "We want to keep it that way." One of the most shocking revelations the CDC shared was the truth behind what causes your eyes to become red and irritated after swimming in the pool.And it's not the chlorine. "It's quite the opposite," said Beach. "Chlorine binds with all the things it's trying to kill from your bodies, and it forms these chemical irritants. That's what's stinging your eyes. It's the chlorine binding to the urine and the sweat." Beach went on to say that the cough you can get from an indoor pool is also caused by the chlorine binding to sweat and urine when the chemical reaction irritates your lungs. There's actually been an increase in disease outbreaks from public swimming pools, according to Beech, thanks in large part to those swimming while they have diarrhea. Those with diarrhea don't even have to defecate in the pool to spread disease, but just have the germs on their body, which is why the CDC encourages swimmers to shower before getting in the pool. "We have a new parasitic germ that has emerged that's immune to chlorine," says Beach. "We've got to keep it out of the pool in the first place. We need additional barriers." The misconception that chlorine just eliminates all germs upon contact is untrue, and it takes time to properly disinfect for each germ. While chlorine kills most bacteria such as E. Coli in less than a minute, it takes at least 16 minutes to kill Hepatitis A, and the Cryptosporidium parasite can last in the swimming pool for over 10 days. The CDC claims the only way to prevent recreational water illnesses is to keep germs out of the pool in the first place and to practice the following steps for healthy swimming. Stay out of the water if you have diarrhea. Shower before you get in the water. Don't pee or poop in the water. Don't swallow the water. Take kids on bathroom breaks. Check diapers, and change them in a bathroom or diaper-changing area -- not poolside -- to keep germs away from the pool. Reapply sunscreen. Drink plenty of fluids.