LEIDEN, Netherlands, Dec. 17 (UPI) — People who love horror movies often say they enjoy the unexpected adrenaline rush of gruesome, surprising scenes often described by critics and fans alike as “bloodcurdling,” a metaphor that may have more truth to it than previously thought.
Researchers at Leiden University Medical Center in the Netherlands tested the physiological effects of horror movies on a group of volunteers, finding fear inspired by a horror movie increased levels of clotting agents in viewers’ blood.
While they said this doesn’t mean people’s veins will start clogging while binging on the Freddy Krueger or the Saw movie series, it does mean the term is somewhat literal.
“For centuries the term “bloodcurdling” has been used to describe feeling extreme fear under frightening situations,” researchers wrote in the study, published in the British Medical Journal. “The term dates back to medieval times and is based on the concept that fear or horror would ‘run the blood cold’ or ‘curdle’ [congeal] blood.”
The researchers recruited 24 healthy volunteers from the hospital under age 30, showing 14 the movie Insidious and then a documentary called A Year in Champagne separated by a week, while the other 10 were shown both movies a week apart in the reverse order. The researchers took blood samples from each participant 15 minutes before and after watching each movie.
Insidious was expectedly found more frightening by viewers than the documentary, and levels of coagulating factor VIII increased in 57 percent of participants, as opposed to just 14 percent of participants’ levels going up during A Year in Champagne. During the documentary, 86 percent of the participants’ levels decreased, compared to 43 percent during the horror movie.
The researchers said they think the increase in the clotting factor is the body preparing to heal itself as a physical response to fear — if a person is running from an animal attack but is caught, the body’s preparation could help stop bleeding faster, they explained.
“We suspected that fear might speed clotting in the blood,” said Nemeth Banne, a researcher at Leiden University Medical Center, in a press release. “Damaged tissue gives off tissue factor, which triggers the coagulation really, but that’s probably faster if there are more clotting factors in the blood.”
