Watching horror films can help you burn off the amount of calories contained in a small chocolate bar, researchers say.
Scientists at the University of Westminster tested ten people as they watched a selection of classic scary movies.
They monitored the viewers' heart rate, oxygen intake and carbon dioxide output to work out how much energy they were using, the Daily Mail reported.
On average, participants used up a third more calories watching the scary films than if they had been sitting in front of a blank screen.
They burned an average of 113 calories over 90-minutes of film watching - the same amount as a 30-minute walk - which would off-set the calories in a small chocolate bar.
However, the films that made viewers jump in terror were the best calorie-burners because they cause the heart rate to soar.
The 1980 Stanley Kubrick psychological thriller The Shining, starring Jack Nicholson, was the best for calorie busting, with the average viewer using up 184 calories.
Steven Spielberg's 1975 film Jaws was next in line, with viewers burning on average 161 calories, while the 1973 classic The Exorcist, starring Max von Sydow, came third, using up 158 calories.
"Each of the 10 films tested set pulses racing, sparking an increase in the heart rate of the case studies," Dr Richard Mackenzie, a metabolism specialist at the University of Westminster, told The Guardian.
"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."
Helen Cowley, of movie rental company LOVEFiLM, which teamed up with the university for the study, said: "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."
Top 10 energy-burning scary movies
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
- www.nzherald.co.nz, DAILY MAIL