Tuesday January 28 2020
May 29, 2013

Why Do We Need to Pee In Our Wetsuits?

Okay, let’s face it! We all know but keep it as a secret that we really need to pee in our wetsuits underwater. If a scuba diver says “Hey! I have never peed in my wetsuit”, he is possible lying unless he has been diving for two weeks. Today, in Dive With Seaman Facebook Page, I have asked my readers to be honest and tell me if they pee in their wetsuit or not. It has been like six hours but nobody has answered yes!! On the other hand, nobody has answered NOOO either..

 Is It a Shame to Pee in Our Wetsuits?

In fact, the “pee” is organic and it is 95% water. Pee also consists of urea, ammonium, phosphates, calcium, sodium, uric acid, sulfates, magnesium, potassium and cretonne. If I would mix these in a bottle one by one and pour it to my wetsuit, then you guys were not going to tell me that this is disgusting. Because you were not going to know the name of it. But when we call it “pee“, it makes us feel obscene. I think the criminal is ammonium here, because it has a bad odor, doesn’t it?

 The Logic Behind Peeing

So, why do we pee? Simple. It is because our body wants to balance the volume of “liquids” in us. Let’s go a little bit narrower.

When you drink high volume of water (hydrate), water goes to the veins and our volume of blood increases. But our body wants (and also needs to) to have a stable volume of blood. When this high volume of blood reaches your heart, it says to your kidneys: “heeey! there is too much blood here and I am tightened! Would you please decrease the volume?“. And your kidney answers: “Alright captain, cool down. I will produce some urine and make this guy (you) pee to get rid of some liquid and have an acceptable volume of liquid again“.

Okay, right now we know the mechanism of peeing. But I can hear the questions from you: “I am NOT drinking so much water before my dives but I am still having the need of pee in my wetsuit!”. I will tell you the reasons below.

 Need of Pee in Our Wetsuits Underwater

If you have dived even for once, I am sure you have realized that you need to pee much more than you do on the land. This increased “need to pee” has two specific reasons. One of them is known as “cold water immersion diaresis“. It simply occurs in temperature changes (from warm to cold). In fact, we are all experiencing this when we get out of our warm houses in winter. And when we start walking on the street, “need for peeing” begins (talk about this more in minutes)

Other reason is the “non-gravity“. Think about astronauts. They suffer from problems caused by non-gravity when they return Earth. The blood cannot circulate well in extremities (legs and arms) without gravity. The majority of the blood is gathered in chest.

Let’s talk about each factor more detailed.

Cold Water Immersion Diaresis

What a scary name, isn’t it? But don’t worry. When we move from a warm place to a colder place, our body wants to save our brain and heart by gathering blood in these organs. Our veins feeding our extremities get narrower to be able to save the valuable blood in the chest area. In fact, this reaction is a part of Mammalian Diving Reflex.

Mammalian Diving Reflex is commonly used by dolphins and seals… And human-beings as well (free divers use it for staying more underwater). Mammalian Diving Reflex consists of 3 levels:

Bradycardia: When divers contact the water by face, their heart rate decreases by 20% on average (it may decrease by 50% in trained people).

Peripheral Vasoconstriction: This is the phase I have mentioned above. Our veins feeding our arms and legs get narrower, resulting the blood to get collected in the chest area. This is both for saving enough oxygen and heat for brain and heart (vital organs).

Blood Shift: If a diver is deep diving, the blood plasma and the water can get through our organs like our lungs. This mechanism helps us to save our organs from increased pressure. When there is water inside and outside, the pressure is equalized as you know. When the pressure is decreased (when we surface), the blood plasma and the water in our lungs are cleared after a deep dive.

So, when we feel cold underwater, our blood is collected in our chest area for several reasons. The total volume of the blood is in fact constant. But because it is all collected in the chest area, our brain gives its command to the kidneys (as we have already discussed), urine is produced, need to pee occurred…


When we have a perfect buoyancy underwater (read the buoyancy article for more information about hovering underwater), we don’t have a gravity on us. The gravity is a must for a healthy circulation system. I am sure you have seen medical professionals and first aid personnel interfering a victim. If there is a cut in victim’s arm, for example, the medical personnel raise that arm. Why? Because they want to reduce the blood circulation of this arm. Normally, the heart feeds that arm by the help of gravity. When the arm is raised above the heart level, the heart cannot pump enough blood to that arm. You can understand how the gravity is important in our circulation system.

Let’s return to our topic. when a diver has a perfect buoyancy underwater (this is a scuba diver’s number one wish), the non-gravity occurs and the blood is again gets collected in the chest part. Just like in Cold Water Immersion Diaresis, our heart will give the command to the kidney to produce urine. Then we have the need to pee again!

 So, what?

This is the question. The need to pee underwater is N-O-R-M-A-L. Of course it is your choice to pee but if the wetsuit you are wearing is yours, I advise not to struggle with this need. Don’t be shy ! Just remember NOT to wash your wetsuit in a tank that the other divers wash their regulators please !! If you have rented a wetsuit, it may not be that ethical to pee, because someone else is going to wear it. And he/she may not be thinking like “it’s ok, it is just 95% of water and a little bit of other stuff”.

But from now on, you know that the need to pee in your wetsuit is normal and every scuba diver is experiencing this. Feel the Cold Water Immersion Diaresis and non-gravity in your next dive and remember this article.

You can, for example wear a dry-suit to stay warmer underwater and eliminate the Cold Water Immersion Diaresis. This will really decrease your need to pee.

But the non-gravity will still be with you.

Last but not least, don’t stop drinking fresh water before your dives. Not drinking water will not decrease your need to pee in your wetsuit (maybe a very little bit). Drinking water will help you (in avoiding cramps for example, its main cause is dehydration) underwater.



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About Seaman


Hi, my name is Murat Demirağ. I have been diving since 1996 and teaching scuba since 2005. I wanted to share my knowledge through divewithseaman.com

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  • Husnu Yucel 'Hugo'
    2013-05-29 21:16

    Answer of your question is no. As a non-pee person while diving; that’s not a big problem, but while unfixing the scuba and the boat trip to resort is a nightmare:)

    • Seaman
      2013-05-30 01:43

      Hugo, when it gets colder in winter, let’s discuss this one more time. Colder water => More blood getting collected in the chest => More need to pee unfortunately. But yeah you are one of the fellow divers I have seen not peeing yet. lol

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