It's not uncommon to see a character in a horror movie say we were "scared to death" by a villain or a specter.
Usually we're able to shake off our sweaty palms and our terrified expression by the next scene.
But one doctor says being "scared to death" may be more fact than fiction.
Martin A. Samuels, a neurologist at Brigham and Women's Hospital in Boston, says it's possible to die from intense fear.
"Can one be scared to death? Yes," he said. "There is unequivocal evidence that one can be scared to death under certain and very specific circumstances."
Samuels has dedicated his life to exploring sudden death.
After studying hundreds of cases, he says his theory is that catastrophic events -- like the Sept. 11, 2001, attacks; an earthquake; or the loss of a loved one -- can cause someone to literally be scared to death.
"I know this because I have cases of children with absolutely no heart disease who died on amusement-park rides," Samuels said.
Samuels is not referring to an everyday heart attack brought on by mild stress, but rather a shock to the heart caused by chemicals sent out by the brain.
"It would be like getting an enormous dose of speed or ecstasy," he said.
'Lightening Bolt' Can Set off Deadly Chain of Events
According to Samuels, the catastrophic event can be like a lightening bolt to the heart that is fueled by a series of internal chain reactions that begin deep in the brain -- what scientists call the "fight or flight" response.
"You're just minding your business going home one day and somebody puts a gun to your head. 'Your money or your life,' he says. It's not a game," he said.
Many people have probably felt an adrenaline rush during a traumatic event.
That rush can set off a life-threatening process: Pupils dilate, muscles prepare for action, and the heart is flooded with chemicals from the nervous system.
For most, the process ends there without injury.
"This chemical goes back into the bloodstream. The heart goes back to normal, and we walk away," Samuels said.
But the neurologist believes that for a very rare few, if they're scared enough and feel there is no escape route, that jolt of chemicals can physically damage the heart.
In extreme cases, it can cause sudden death.
"My own view is that any human is potentially at risk. We all carry this little bomb inside us," Samuels said. "We're all at risk. If the situation is just right, if the stress is bad enough, if it's acute enough, if there's no way out, any of us can die."
Take the case of Kenneth Lay, the former Enron chief who died in July 2006 while awaiting sentencing for conspiracy and fraud.
Lay's doctors called his death a heart attack. While Samuels hasn't examined Lay's heart, he speculates the cause could have been something else.
"He was in his 60s, probably going to prison, probably for life, nothing he could do about it," he said. "All you could say is that it is the perfect set up for the sudden death."
A death so fast and intense, it's impossible to predict, or ever know for sure whom it could strike.