Why do you want to urinate when you hear the sound of running water?

2021-04-02 | Weird Rokop Original |

Many people have experienced this feeling in their lives: the urge to pee when they hear the sound of running water. Specifically, there are many situations.

For example, some people have the urge to urinate when taking a bath, some people are filling hot water, and some people are washing their hands with a tap...

In addition to complaining about what kind of ghost reaction this is in the case of "impatient", most of the time we are accustomed to this and don't care about it.

Then why do we have such a peculiar response to the sound of running water? Before explaining this question, let's talk about how the human body urinates.

How does the human body urinate

Urine is a liquid excrement produced by the body's metabolism. The blood flowing through the kidneys will be filtered by the kidneys. After one filtration, it is called original urine, and after filtration again, it becomes final urine, which is urine.

Final urine that has been filtered with part of the water and nutrients will be concentrated in the renal pelvis, and then flow into the bladder through the ureter. These processes are not controlled by the body.

The bladder is a storage organ for urine. A normal bladder can hold 500ml of urine. It takes about 2 to 5 hours to urinate once.

Urine enters the urethra from the bladder and is controlled by the sphincter. It is two ring-shaped muscles. One is at the top of the urethra. It is controlled by the parasympathetic nervous system and is autonomous.

The other is at the outer mouth of the bladder. Although it is also autonomous, it can be controlled by us. This is why we can hold back urine.

When the urine in the bladder is full, the baroreceptors on the bladder wall will send a signal to the brain, so we have the urge to urinate.

At the right time, our sphincter will relax, and at the same time, the detrusor in the bladder will contract. Under the action of the two muscles, urine will be discharged.

How does the sound of water flow affect urination

In the scientific community, there is no clear answer as to why people will feel urine when they hear the sound of water flowing. People agree with the view that this is a classic conditioned reflex.

Conditioning is an acquired response to a stimulus. The simplest example may be Wangmei quenching his thirst; non-conditioned reflex is innate, such as blinking.

The most famous example of classic conditioned reflex is Pavlov’s experiment with dogs. He successfully taught the dogs to react to the bell.

We know that dogs secrete saliva before eating, because saliva can moisturize the mouth, soften food, and sterilize and maintain oral health.

In the beginning, it didn’t matter whether the dog salivated or not, but Pavlov would ring the bell every time before feeding the dog.

Over time, even if there is no feeding, when Pavlov presses the bell, the dog will salivate, and he thinks the owner is about to feed him.

Pavlov’s dog begins to salivate as soon as he hears the bell, and people always want to urinate when they hear the sound of water. These two processes are actually very similar.

Salivation is a natural response of dogs, which is unconditioned and has nothing to do with the ringtone; while people's urination is also unconditional, which has nothing to do with the sound of water.

The bell makes the dog experience the anticipation of food coming, and the sound of water similar to urination makes us experience the satisfaction of "bladder liberation".

How did we "learn"?

The reason why the dog responds to the bell is because Pavlov uses the bell to stimulate the dog every time before feeding. It can be said that Pavlov taught it.

Then how do we humans learn to respond to the sound of water flowing? Some people may say, because we hear that sound when we relieve ourselves from childhood, and we learn every time we relieve ourselves!

It makes sense to say this. Using the same principle, we can also explain why sometimes the urge to urinate occurs when entering the bathroom or seeing the bathroom sign.

However, there is another possible explanation for this problem: we don't necessarily learn this reaction after birth, but learn it a long time ago.

And this "early" is very early, perhaps as far back as our furthest ancestor-ancient mammals.

According to the analysis of fossil evidence held by humans, mammals on the earth first appeared more than 200 million years ago, which is the so-called orc.

At that time, the ruler of the earth was dinosaurs, and dinosaurs were divided in size, but there is no doubt that they were stronger than most mammals.

In order to avoid the attack of powerful predators, mammals must live carefully, and they cannot even urinate anywhere, because that would expose their location.

Then how to deal with urine? The way mammals come up with is to release it in the river or in the downpour, because the smell can be diluted to the greatest extent.

Before they replaced the dinosaurs, this "living" method lasted for a long time. This was the earliest conditioned reflex learning.

After the rise of mammals, they no longer worry about where to urinate, but due to evolutionary advantages, the unconscious connection between this response and the sound of running water has been retained.


It is not a bad thing to think to urinate when you hear the sound of water flow. On the contrary, it is actually very likely to "secretly" guide our "urination pattern".

At least, when you want to urinate, there is such an ancient and simple method to choose from.

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