Horror health warning? Scary films really can curdle the blood

Dutch study finds watching a frightening movie lifts level of protein factor VIII, which contributes to blood clotting

The "bloodcurdling" horror film has long been an advertising staple in the movie industry, alerting fans to the most gruesome Hollywood releases. And now, thanks to a group of enterprising if tongue-in-cheek researchers, the effect has been proven as a medical reality.

A study by doctors and academics at Leiden University in the Netherlands analysed blood samples from volunteers who had just watched either a horror film or a distinctly non-frightening documentary about the French wine industry. It found that those who sat through the horror title had higher levels of the blood-clotting protein factor VIII.