No one agrees from a medical standpoint as far I’m aware. The argued theory is that it is caused by a nervous system trigger.

I’ve read that immersion diuresis causes it, but wiki disagrees. Most likely it has to do with the parasympathetic nervous system. I could only find one article, not the one I wanted but it works. sort of the same idea

why do you want to know?

@cdwccrn: Hey, I’m interested.