Want to lose weight without moving? Try watching a scary movie.

Researchers claim that instead of working up a sweat, sitting on the sofa and watching adrenaline-pumping horror movies can help burn as many calories as a 30-minute walk.

The only catch is that the movie has to be scary, and the scarier the movie, the more calories you'll burn.

Researchers at the University of Westminster monitored 10 participants as they watched a selection of classic horror films. Researchers monitored the participants' heart rate, oxygen intake and carbon dioxide output to calculate how much energy they burned.

The study, sponsored by website LOVEFilm.com, found that on average participants burned a third more calories watching horror flicks than if they had been sitting in front of a black screen.

Researchers said that over 90-minutes of film-watching, participants burned 113 calories on average, which is roughly the same amount of calories burned as a 30-minute walk or the calories contained in a small chocolate bar.

Researchers explained that horror movies that viewers jump in terror burned calories because they cause the heart rate to soar.

"Each of the ten films tested set pulses racing, sparking an increase in the heart rate of the case studies," cell metabolism expert Richard Mackenzie said in a statement, according to The Telegraph. "As the pulse quickens and blood pumps around the body faster, the body experiences a surge in adrenaline."

"It is this release of fast acting adrenaline, produced during short bursts of intense stress (or in this case, brought on by fear), which is known to lower the appetite, increase the Basal Metabolic Rate and ultimately burn a higher level of calories," he added.

"We all know the feeling of wanting to hide behind the sofa or grab a pillow when watching scary or hair raising scenes. This research suggests that maybe those seeking to burn some calories should keep their eyes on the screen," Helen Cowley, of movie rental company LOVEFiLM, said in a statement, according to the Daily Mail.

The study found that the top 10 calorie-burning horror films were:

1. The Shining - 184 calories  2. Jaws - 161 calories  3. The Exorcist - 158 calories  4. Alien - 152 calories  5. Saw - 133 calories  6. A Nightmare on Elm Street - 118 calories  7. Paranormal Activity - 111 calories  8. The Blair Witch Project - 105 calories  9. The Texas Chain Saw Massacre - 107 calories  10. [Rec] - 101 calories