Maybe you've experienced this before: 

you go to the washroom, start to pee, and all of a sudden you're hit with a jolt of shivers through your entire body. It typically occurs near the last couple second of your... er... "performance" and lasts for only a second before it's gone.

Pee shivers, otherwise known as Post-Micturition Convulsion Syndrome, is a fairly common occurrence in everyone, though more men have reported experiencing it than women. As you'll read below, the fact that more men experience this than women has more to do with the fact that many men stand when they pee, and many women sit.

So, why does it happen? 

Let's start with the bad news: unfortunately there hasn't been a whole lot of funding allotted for pee shiver research, so nothing conclusive has been drawn. However, there are a couple interesting theories about the sensation. 

Theory One: Blame your parasympathetic nervous system

Your what?? Your parasympathetic nervous system is the system responsible for the "rest-and-digest" functions in your body. You know the feeling when you are just about to pee, how there's a shift from the feeling of "holding it in" to "now I'm really doing this"? That shift, (the initiation of urination, if you will), is prompted by the parasympathetic nervous system, by lowering the body's blood pressure. 

When your blood pressure drops, your body responds by firing out catecholamines (chemicals like dopamine or hormones like adrenaline) to regulate levels again. On the way, those tiny flashes can result in you guessed it a pee shiver. 

This brings us back to the reason why more men have reported this feeling than women when you stand, you are likely to feel a blood pressure drop more strongly. 

Theory Two: You're Getting Colder

This theory is probably the simplest to explain. I don't know if you've ever felt your pee (yeah, me neither) but it's actually pretty warm. It's kept warm inside your body. When you pee, all that warm fluid rushes out of your body, which lowers your overall temperature very quickly leaving you to react the same way you would in a cold breeze... with a shiver. 

That's all she wrote, folks! 

If you're thinking of donating a mass amount of money to scientific research any time soon, or becoming a scientist yourself, it looks like there are plenty of untapped opportunities in the pee shiver market. Until then, I hope you continue to enjoy the mysteries of the body!

Thanks for reading!

Sources: 1, 2, 3