Three miles off the coast of Placencia, Belize on a boat, suiting up for a dive, the conversation turned to the second most common dive conversation after “All things Turtles”, and that conversation is about ‘Pee’.
When you dive, you pee. It’s such a consistently observed phenomenon that even without empirical study, one could upgrade it past theory and right into physical law. Just like I know that when i jump out a window I will splat on the pavement, I know that when I jump off a dive boat, no matter how empty my bladder at the time, I will pee. It’s like the 5th law of thermodynamics: When you dive, entropy increases as you pee. Of course, this would be labeled the 4th law because stupidly, they zero-based numbered them and there is actually a Zeroth Law of Thermodynamics. So yeah, that oft-quoted Second Law of Thermodynamics? It’s actually third on the list. Mind = Blown. Which increases entropy and hence, obeys the third… i mean second law of thermodynamics.
So yes, you pee. It’s fine. Wetsuits trap water, but there is still a steady exchange across the membrane of the wetsuit that flushes it out.
However, this is why I have never, and will never, dive in a “dry” suit. Cuz no, ick, ew. While I would never kink-shame anyone for what they do in the privacy of their own bathtubs, I don’t need to commingle my hour under the sea observing the awe-striking beauty of nature with some kind of adult diaper fetish. That kind of multitasking diminishes both experiences.
Anyhoo, one particularly meticulous man in a pricey Blueseventy couture cerulean wetsuit with matching headpiece adorned with marine-themed accouterments chimed in:
“I don’t pee in my wetsuit,” he said.
“Yes, you do,” I responded.
“No. I don’t”
“Yes. You do.”
We went back and forth on this til we jumped off the boat. Later, at 80 feet, I wrote on my white board “Yes you do” and flashed it at him. Although I think I was suffering from nitrogen narcosis at the time because after the dive I looked at the board and it said “Turtle!”
Anyschmoo, I decided to investigate this issue, find proof that this is a real physiological phenomenon, and rub his face in it. The evidence, not the pee. Or both if he asked nicely. My research led me to something I had read about before called ADH, Antidiuretic Hormone.
ADH, also called arginine vasopressin, because naming things is hard I guess, is secreted by the hypothalmus AND the posterior pituitary gland, because redundancy is redundant. ADH regulates the amount of water in your circulatory system and it’s release from whichever of the two glands decides to step up first, is triggered by osmotic sensors and baroreceptors monitoring electrolytic concentration and blood pressure respectively.
Antidiuretic means ‘prevent diuresis’, obviously, so ADH _prevents_ urination. So when elctrolytic concentrations are low and BP is high, the hypothalmus or the posterior pituitary _stop_ producing ADH to allow for diuresis. ADH prevents dehydration, it does not prevent you from volumetric explosion.
When we dive two things happen. Cold water causes peripheral vasocompression sending more blood to the body core. Also, when we are buoyant in water, gravity no longer is dragging our blood toward our feet, also increasing the volume of blood in the body core. This central blood volume spike triggers osmotic receptors and baroreceptors to inform those two glands to stop producing ADH. Then the kidneys just start producing urine willy-nilly and an irresistible flow comes out of your willy-nilly into your wetsuit. Even if its a rental. Yes, that wetsuit you are renting has been peed in.
Back on land, warm, re-victimized by gravity, ADH is again produced and we get thirsty. We rehydrate. We start the process over and over again.
Take THAT cerulean wetsuit dude who probably watched The Devil Wears Prada too many times and hence bought a cerulean wetsuit!