It might not feel like it, but the adult bladder can hold as much as half a litre (2 cups) of pee before you'll feel the need to 'go'. Your body knows how much is in there because your bladder wall is filled with tiny receptors that send a message to your brain when the bladder reaches capacity. Fortunately, most of us have full control over our bladder function, so when we receive this message, we can choose to either relieve ourselves right away, or hold it because it's a really long way to the bathroom from the couch. But what exactly are we doing to our body when we hold all that pee in?
In the latest episode of SciShow, Michael explains that once you've made the decision that you're too busy to pee right now, the cylindrical sphincters in your bladder close up tightly to keep all of the urine from leaking through your urethra. These little muscles are great at what they do, until you make them do it consistently for a really long time, say if you're a trucker and you're holding in your pee on long trips several times a week.
If you make a habit of holding in your pee for ages, you're subjecting yourself to pretty serious long-term effects, including a higher risk of infection. And as the video above explains, constantly holding in your pee can weaken your bladder muscles, which could lead to urinary retention - the dreaded condition that prevents you from being able to fully empty your bladder when you pee, which means you feel like peeing a lot.
Holding in large amounts of urine for an extended period of time also exposes your body to potentially harmful bacteria, which can increase your chances of getting a urinary tract infection (UTI) or bladder infection.
All of which sounds pretty bad, but not exactly life-threatening, right? Well, you're just not trying hard enough.
Enter Tycho Brahe: a Danish astronomer and alchemist back in the 16th century. Brahe was a fantastic scientist, contributing to the scientific literature on everything from supernovae, comets, and planetary orbits. He also ended up in a duel with a fellow nobleman over the legitimacy of a mathematical formula, and because they chose to duel in the dark, he ended up losing the entire bridge of his nose. For the rest of his life, Brahe glued a silver or gold nose replacement onto his face.
As colourful as all that is, Brahe's cause of death is perhaps even more ridiculous. He reportedly refused to leave a banquet to relieve himself because he believed it to be a breach of ettique, but then once he got home, he found he was unable to pee at all. He descended into delerium and died soon after when his entire bladder burst.
The good news is that Brahe's bladder wasn't like most - in the vast majority of cases like this, a person will just wet themself before any bursting occurs. If bursting happens, it's almost always because the bladder was already damaged for some reason. But not always. As Michael explains in the video above, there have been cases where people's bladders burst because they were too drunk to notice the signal from their brain telling them to pee.
Can't get enough of pee? Well, you're in luck, because Destin from Smarter Every Day just happened to visit NASA recently to find out why they burn astronaut pee. They don't call it a national treasure for nothing: