The Dangers of Holding in Your Pee, According to Science

iStock / iStock

Maybe you drank too much water before sitting down for a meeting. Maybe it was a long car trip where no one else had to go and you didn't want to request a bathroom break. Maybe you guzzled a 54-ounce soda during Titanic and decided to tough out the last 45 minutes.

However it's happened, you've probably found yourself flexing your pelvic muscles to act as a dam against a tsunami of urine until you had the right opportunity to relieve yourself. And you may have wondered what—if any—damage you were risking in denying your body a chance to remove all that waste. Will your bladder explode? Will you pee your pants? Are you inviting permanent and embarrassing pee-related trauma to your body?

"As a one-time thing, here or there, the majority of people with normal urinary tracts are probably not doing any harm in the long run," Howard Adler, medical director of the prostate care program and clinical associate professor of urology at Stony Brook Medicine, tells Mental Floss.

The key, Adler notes, is "here or there." The average number of times people need to urinate in a day ranges from four to seven and depends on your hydration level. If you are a chronic pee pauper who holds it in several times a week, you're flirting with a few uncomfortable consequences.

One of the more well-known categories of people who voluntarily hold in their urine are nurses, who are often so busy on long eight to 12 hour shifts that they don't take the time to relieve themselves. Experts have dubbed the habit “infrequent voiding syndrome” (and it's also known as having "nurse's bladder"). A 1991 study of 72 female nurses found that those who habitually avoided the bathroom had actually enlarged their bladder capacity, from the norm of 500 milliliters up to 1100 milliliters, or from about 16 ounces of liquid to 37 ounces. (One water bottle is 16 ounces.)

No other adverse effects were noted, although over time, stretching the bladder to elephant-sized proportions (metaphorically speaking; an actual elephant bladder holds about 42 gallons) could eventually result in urination changes: Retaining that much urine can weaken pelvic floor muscles, making it harder to maintain control over the urge to go. Rarely, infrequent voiders might also develop a urinary tract infection or kidney damage from retaining urine; if they drink less to avoid using the bathroom, they might potentially develop kidney stones.

But can the combination of a Big Gulp and a highway logjam create an actual medical emergency? Adler says that while it's "theoretically possible" that a bladder could burst from too much urine, it probably won't unless the organ is damaged from outside forces. Someone drinking too much and then getting into a traffic accident could perforate their bladder during a collision, for example. It's also possible you could pee your pants, but it's infrequent.

Adler stresses that infrequent voiders are typically avoiding relief for eight hours or more, so a long movie or two-hour meeting probably isn't going to do any damage. People tend to make 1–2.7 ounces of urine per hour. Even if you're guzzling water, it'll be some time before your bladder is at max capacity and you're in pain. Hold it if you need to, but don't make a habit of it.