Why does diving make you pee?

[Sexismygod 1,782]

As a diver for almost 20 years, I've noticed a common phenomenon countless times:  When the divers get back on the boat, there's always a mad scramble for the loos.

I'll skip the joke about peeing in your wetsuit or lying about it ... the truth is, most divers do not pee in their wetsuits.  They don't really want to swim in their own pee for an hour (I'm in that group, too).  There are some that do and that's fine, but you can always identify their suit after 3 or 4 days of diving.  To be blunt, it's smells like piss, especially if you're diving somewhere hot.  Surprise!

The interesting thing is that every diver needs to pee when they get out of the water.  It's like a law of nature.  Because of this, most divers hit the head immediately before going in.  They drink nothing while diving, obviously (ok, I've tried to drink underwater, it's actually surprisingly difficult).  They're only in the water for about an hour.  But when they get back to the boat, they NEED TO PEE!

I find its worst after a night dive but that may be because I'm pretty cold-tolerant so don't usually wear a wetsuit, just shorts, so I pee during day dives.  I always wear a wetsuit at night because it's so much easier to bump into things in the dark.  If I can't pee during the dive, I'm like every other diver ... I need a pee ... now!  Cold water diving is similar (never, ever, pee in a dry suit!).  This is exacerbated by the time it takes to get out of a drysuit.

So the question is ... what causes this phenomenon?  Why do divers need to pee after a dive?  If anyone has a proper scientific explanation, I'd love to hear it.

Edited November 14, 2021 by Sexismygod

[jahman22 33]

I'm also a diver, freediver actually. I think having to pee while diving in is the same phenomenon as being in the shower.
I hate peeing in my wetsuit, did it for many years but the type of neoprene we use doesnt allow liquid in or out so it really sticks with you so I try and pee between dives. We have to lube our wetsuits to get them on, Usually with conditioner. The combined smell is just weird. I know the water will make me pee so I try and do it before or in between dives and not be stuck with that smell all day.

When there are girls on the boat freediving, they almost always squat off the back before getting into their suit then will piss in that suit all day long, even sometimes getting back into the water, fully suited, just to pee. Sounds more appealing then it is, I much prefer a quick glance when they squat off the side. 

 

[Sexismygod 1,782]

@jahman22  I didn't know that about free-diving suits.  I guess the tightness reduces water flow even more for better thermal protection.  Scuba wetsuits are usually not that tight.

For me, being in the shower only makes me want to pee if I already need to go.  If I don't need a pee, the shower doesn't really cause any additional need.  But the shower is warm water.  Maybe there's a physiological response to being immersed in "cold" water for a prolonged period.  Cold in the sense that it's more than 5c below body temperature.  Most of my diving friends say the urge hits after about 30-45 minutes.  They often complain about discomfort on the safety stop (something free divers don't need to worry about ... lucky them).

How long do you stay in the water when free diving?  I assume you'll do multiple dives, not just one.  Do you stay in the water between dives?

[jahman22 33]

5 hours ago, Sexismygod said:

@jahman22  I didn't know that about free-diving suits.  I guess the tightness reduces water flow even more for better thermal protection.  Scuba wetsuits are usually not that tight.

For me, being in the shower only makes me want to pee if I already need to go.  If I don't need a pee, the shower doesn't really cause any additional need.  But the shower is warm water.  Maybe there's a physiological response to being immersed in "cold" water for a prolonged period.  Cold in the sense that it's more than 5c below body temperature.  Most of my diving friends say the urge hits after about 30-45 minutes.  They often complain about discomfort on the safety stop (something free divers don't need to worry about ... lucky them).

How long do you stay in the water when free diving?  I assume you'll do multiple dives, not just one.  Do you stay in the water between dives?

Our suits are 2-piece so if on a boat I can easily pull the top up, whip it out and go off the boat and not not in my suit im wearing all day. Sometimes I'll swim back to the boat to just to pee off it. Sometimes on shore dives I just have no choice and have to go in my suit because the urge to pee overwhelms me and I don't want to swim to shore and end the dive early. 

 

 

 

[Alfresco 11,637]

The phenomenon is common in divers and swimmers and indeed anyone spending time in the water - even when you go to the local swimming pool for a quick dip.  It is known as immersion diuresis.

See link below for more info and an explanation of what causes this to happen.

https://dan.org/health-medicine/health-resources/diseases-conditions/immersion-diuresis/

[Sexismygod 1,782]

16 hours ago, Alfresco said:

The phenomenon is common in divers and swimmers and indeed anyone spending time in the water - even when you go to the local swimming pool for a quick dip.  It is known as immersion diuresis.

See link below for more info and an explanation of what causes this to happen.

https://dan.org/health-medicine/health-resources/diseases-conditions/immersion-diuresis/

Thanks for digging that up @Alfresco   👍