Could Watching Horror Movies Lead to Blood Clots?

The term “bloodcurdling” originates back to medieval times and stems from the concept of feelings of fear or horror causing the blood to “curdle”, but until now the theory has never been verified.

Horror movies are blood-curdling in more ways than one, a recent study featured in the Christmas edition of the British Medical Journal has revealed.

Washington D.C, Dec 17: When it comes to horror movies, the term “bloodcurdling” may not be a hyperbole after all, according to a new study.

While 14 of them watched the scary movie – 2010 box office hit Insidious, starring Patrick Wilson and Rose Byrne – followed by educational film A Year In Champagne, the remaining 10 watched the flicks in reverse order.

The team at Leiden University Medical Center studied 24 healthy volunteers ages 30 and younger. Both films lasted about 90 minutes each. Everyone watched their assigned movies more than a week apart, and at the same time of day, getting blood drawn before and after each movie.

Blood samples of each volunteer were taken before and after each movie and were analyzed by scientists who searched for any clot formations.

Levels increased in 57 percent of the participants during the horror movie, but only 14 percent during the educational movie.

Levels decreased in 18 (86 per cent) participants during the educational movie but only in 9 (43 per cent) during the horror movie. Participants were also responsible for rating their fear on a visual analogue fear scale ranging from 0 (no fear) to 10 (the worst fear imaginable).

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.

However, the researchers found no effect of either movie on levels of other clot-forming proteins, suggesting that although “curdling” is triggered by intense fear, it does not lead to actual clot formation.

While the volunteers watched the popular horror movie, the Factor VIII raised over 11 IU/dl, which is associated with high risk of blood clot or thrombosis.