Why Do People Lose Control of Their Bladders When Frightened?

Answers to your questions about the news.
Oct. 25 2011 6:21 PM

Can You Be Scared Enough To Pee Your Pants?

Some people urinate when they're frightened. Other people can't urinate when they're nervous. What's going on?

Hose spraying
Why do things like fear or running water affect our bladder control?

Photograph by iStockphoto/Thinkstock.

NASA agents burst into a Denny’s in Southern California five months ago to arrest a 74-year-old grandmother who was trying to sell a moon rock to raise money for her son’s medical expenses, according to a recent AP report. The elderly woman told a reporter that she was so terrified during the sting that she lost control of her bladder. Why do people become incontinent when frightened?

Blame the limbic system. Bladder control requires a sophisticated interplay of brain regions. An area of the brainstem known as the pontine micturition center is in constant contact with the bladder. It knows when pressure is building, and makes the preliminary decision to void. Thankfully, this area doesn’t have exclusive control over our bathroom habits, or we’d urinate whenever (and wherever) our bladders become full. The prefrontal cortex can override the desire to pee by sending an inhibitory signal to the brainstem. Under stressful conditions, however, the inhibitory signals from the frontal lobe can themselves be overridden by the limbic system, a combination of brain areas that controls the famous “fight or flight” response. When we become stressed or anxious, electrical signals from the limbic system become so intense that the brainstem has trouble following the frontal lobe’s commands. That’s why many people urinate more frequently before important exams or in the starting corral of a marathon. In life-threatening situations, the limbic system’s orders become so urgent that you can’t even make it to the bathroom.

That’s the neurobiological explanation, at least. The larger evolutionary question—of why incontinence might be advantageous in a survival situation—has no satisfying answer. What’s clear is that urinating in the face of danger pervades the animal kingdom. Gazelles wet themselves with a lion in hot pursuit. Pigeons often become incontinent when chased by wild-eyed toddlers. Laboratory rats have a nasty habit of peeing all over researchers’ hands. Some speculate that the instinct is related to the practice of marking territory with urine to prevent conflict. Alternatively, it may be that urinating could put a pursuing predator off the trail. In the absence of a good explanation, you’re free to speculate.

There’s a related condition known as paruresis, or shy bladder. Sufferers find it nearly impossible to urinate in the presence of others. The neurological basis for the disorder is very poorly understood, but it seems to be the neurological opposite of what happened to the target of NASA sting. The inhibitory signal from the prefrontal cortex becomes hyperactive, for some reason. You might think of paruresis as the story of civilization run slightly amok. The brainstem acts on a primordial level, controlling our most basic behaviors. The prefrontal cortex evolved inhibitory centers to control impulses. Without it, we would urinate and defecate freely, and violate all manner of social norms. The importance of these inhibitory centers can be seen in patients with Alzheimer's, stroke victims, and those who have suffered catastrophic brain injuries. Oftentimes, they lose control over their excretory habits.

Got a question about today’s news? Ask the Explainer.

Explainer thanks David Diamond of the University of South Florida, Gary Fisk of Georgia Southwestern University, Roy Freeman of Harvard Medical School, and Gert Holstege of the University of Groningen.

Brian Palmer is Slate's chief explainer. He also writes How and Why and Ecologic for the Washington Post. Email him at explainerbrian@gmail.com. Follow him on Twitter.

TODAY IN SLATE

War Stories

The Right Target

Why Obama’s airstrikes against ISIS may be more effective than people expect.

The NFL Has No Business Punishing Players for Off-Field Conduct. Leave That to the Teams.

Meet the Allies the U.S. Won’t Admit It Needs in Its Fight Against ISIS

I Stand With Emma Watson on Women’s Rights

Even though I know I’m going to get flak for it.

Should You Recline Your Seat? Two Economists Weigh In.

Medical Examiner

How to Stop Ebola

Survivors might be immune. Let’s recruit them to care for the infected.

History

America in Africa

The tragic, misunderstood history of Liberia—and why the United States has a special obligation to help it fight the Ebola epidemic.

New GOP Claim: Hillary Clinton’s Wealth and Celebrity Are Tricks to Disguise Her Socialism

Why the Byzantine Hiring Process at Universities Drives Academics Batty

Moneybox
Sept. 23 2014 3:29 PM The Fascinating Origins of Savannah, Georgia’s Distinctive Typeface
  News & Politics
History
Sept. 23 2014 11:45 PM America in Africa The tragic, misunderstood history of Liberia—and why the United States has a special obligation to help it fight the Ebola epidemic.
  Business
Moneybox
Sept. 23 2014 2:08 PM Home Depot’s Former Lead Security Engineer Had a Legacy of Sabotage
  Life
Education
Sept. 23 2014 11:45 PM Why Your Cousin With a Ph.D. Is a Basket Case  Understanding the Byzantine hiring process that drives academics up the wall.
  Double X
The XX Factor
Sept. 23 2014 2:32 PM Politico Asks: Why Is Gabby Giffords So “Ruthless” on Gun Control?
  Slate Plus
Political Gabfest
Sept. 23 2014 3:04 PM Chicago Gabfest How to get your tickets before anyone else.
  Arts
Brow Beat
Sept. 23 2014 8:38 PM “No One in This World” Is One of Kutiman’s Best, Most Impressive Songs
  Technology
Future Tense
Sept. 23 2014 5:36 PM This Climate Change Poem Moved World Leaders to Tears Today
  Health & Science
Medical Examiner
Sept. 23 2014 11:37 PM How to Stop Ebola Could survivors safely care for the infected?
  Sports
Sports Nut
Sept. 23 2014 7:27 PM You’re Fired, Roger Goodell If the commissioner gets the ax, the NFL would still need a better justice system. What would that look like?