The mystery finally revealed: why do we have to pee when we swim?

Do you feel the urge to pee as soon as you dive into the water? Don't worry, you're not alone and it's perfectly normal! Discover why our body reacts like this and how you can avoid polluting swimming pools with your urine.

The joys of summer and that irresistible urge…

Who has never felt that sudden urge to urinate as soon as he or she starts swimming? With the return of the beautiful days and the approach of , the desire to spend time at the pool becomes more and more present. The summer sensations are there: sun cream, diving, sunbathing while reading a magazine, cool by the pool… But also this irrepressible urge to urinate, which seems to multiply as soon as we enter the water.

Some people don't hold back and relieve themselves directly in the pool, to the detriment of other swimmers. According to a study published in the journal Environmental Science & TechnologyOf the 420,000 liters of water in a swimming pool, about 30 liters is urine. This is a rather small percentage, given the number of people who bathe in the belief that their urine will go unnoticed.

The crucial role of the kidneys and pressure

If you've noticed that your urges to urinate increase as soon as you start swimming, rest assured that there's nothing wrong with your body or your . There is a syndrome called immersion diuresis which causes the body to unconsciously increase its of urine.

Journalist Jake Rossen explains it in the magazine Mental Floss “The blood vessels contract, moving blood to the internal organs. This increases blood pressure, which can stimulate kidney activity because the body seeks to release fluid to compensate for the arterial changes.” The result? An urge to urinate. The kidneys can also react to water pressure, which increases when you swim deep. Blood pressure rises again and the kidneys continue to filter fluid.

The colder the water, the stronger the urge

An interesting aspect of this phenomenon is that the colder the water, the stronger the urge to urinate. So, if you swim in a heated pool, you have no excuse. But if you spend long periods of time underwater, the urge to urinate will come sooner or later. Nerves can also play an important role: many Olympic swimmers have admitted to having to relieve themselves during competitions.

So, should you rush to the bathroom after diving?

In reality, you are free to do whatever you want, but out of respect for the other people swimming with you, it would be best to apply the golden rule: don't do to others what you wouldn't want done to you. So, if you don't want to swim with strangers' secretions, don't force them to share the space with your bodily fluids either. Don't be rude and look for a bathroom.

The bottom line is that the urge to urinate while swimming is a natural reaction of our bodies, including kidney activity and water pressure. So, the next time you find yourself in this situation, remember these explanations and show respect for other swimmers by going to the bathroom.

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