Researchers have warned that urinating in swimming pools could lead to health problems.

The scientists that carried out the research said they found out that compounds in urine mixed with chlorine can cause chemicals that have been linked to respiratory effects in swimmers to form.

They warned swimmers to stop the common practice after analysing samples.

“If swimmers avoided urinating in pools, air and water quality would likely improve independent of other changes in water treatment or air circulation”,  the scientists from China Agricultural University and Purdue University wrote in the Environmental Science & Technology journal.

In carrying out their findings, the scientists combined water collected from swimming pools in China with mixtures meant to mimic the chemical composition of sweat and urine.

Chlorine, used to disinfect pools, reacts with a number of chemicals found in human sweat and urine.

Uric acid, found in urine, accounted for 24 percent to 68 percent (depending on temperature, water pH and chlorine condition) of the by-product cyanogen chloride in the pool water samples.

“Analysis of swimming pool water samples, combined with the results of experiments involving chlorination of uric acid, and chlorination of body fluid analogue mixtures, indicated that uric acid chlorination may account for a large fraction of cyanogen chloride formation in swimming pools,” the researchers say.

Cyanogen chloride can affect multiple organs, including the lungs, heart and central nervous system via inhalation.

“Given that uric acid introduction to pools is attributable to urination, a voluntary action for most swimmers, these findings indicate important benefits to pool water and air chemistry that could result from improved hygiene habits on the part of swimmers,” the team concluded.

In their conclusion, they say exposure to trichloramine at pools has been linked to reduce lung function in adult swimmers, itchy eyes, runny nose and voice loss in lifeguards.