It has been found by researchers that the reason behind red eyes after swimming is urine whereas general perception is that it is caused by too much chlorine. According to health experts from the US Centres for Disease Control and Prevention (CDC), the Water Quality and Health Council and the National Swimming Pool Foundation (NSPF), people urinate in pools so much that it has become necessary to start educating people regarding the malicious effects of urine.

According to Michele Hlavsa, chief of CDC’s Healthy Swimming Program, peeing in a pool leads to depletion of chlorine and produces an irritant, which turns people’s eyes red.

As per Chris Wiant, Chair of the Water Quality and Health Council, “That ‘chlorine’ smell at the pool isn’t actually chlorine. What you smell are chemicals that form when chlorine mixes with pee, sweat and dirt from swimmers’ bodies”.

The CDC and the American Chemistry Council are making people aware regarding healthy swimming in the US. Particularly, swimmers at indoor pools should take care since there can be an increase of irritants in the recycled air. Chloramines can build up in pool water as well, once the air is saturated. That means swimmers without goggles should be extra cautious to keep their eyes shut when they are underwater.

As per the CDC, people should take a shower prior to entering the pool and also ensure that their pool has adequate air flow and good water quality. It was found in a 2009 survey that 1 in 5 persons admitted that they urinate in the pool.