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This article originally appeared on Time.com.

The heart-pounding thrills of a scary movie may come with some health-related benefits, including a calorie burn and a happier mood. But how much you stand to gain from a scary movie seems to depend on how scary you find the film you’re watching—and how much you want to be scared in the first place.

In a 2012 study, funded by the former video subscription service Lovefilm, researchers from the University of Westminster in the UK asked 10 people to watch 10 different scary movies as they monitored heart rate, oxygen intake and output of carbon dioxide. The 1980’s film The Shining, starring Jack Nicholson, topped the list of the calorie-scorching horror films. The person who viewed it jumped and shrieked themselves rid of 184 calories: roughly the number of calories a 140-pound adult would burn after 40 minutes of walking, according to the American Council on Exercise’s physical activity calorie counter. Jaws and The Exorcist took the second and third spots on the list, burning 161 and 158 calories, respectively.

A stressful stimulus—in this case, a scary movie—causes the release of the hormone adrenaline, which cranks up the nervous system’s fight-or-flight response, says Richard Mackenzie, author of the study, who is now at the University of Roehampton in London. Along with getting your heart racing, this response also draws energy from your body’s reserves so that you’re ready to fight or flee as the need arises.

The study was very small, and the findings were not published in a peer-reviewed journal. But there is other research that frightening flicks may proffer benefits. A 2003 study from Coventry University in the UK, published in the journal Stress, found that watching a horror film significantly increased people’s circulating levels of disease- and infection-fighting white blood cells. Again, the study team credits the movie’s ability to fire up the viewer’s fight-or-flight response, which includes a short-term increase in immune function.

It might be simpler to think of horror movies as a form of “good stress.” While stress gets a bad rap—and long-term stress is associated with everything from depression to heart attacks—brief bouts of stress have often been linked to improved immune function and activation, says Firdaus Dhabhar, a professor of psychiatry and behavioral sciences at the University of Miami’s Miller School of Medicine.

A good scare can also elevate your mood. “The research my colleagues and I have done show a high-arousal negative stimuli improves mood significantly,” says Margee Kerr, a sociologist and fear researcher and author of Scream: Chilling Adventures In the Science of Fear. These can be activities like watching a scary movie, or visiting a pop-up haunted house or Halloween-season attraction.

Kerr says that after a scary experience, people feel less anxious, less frustrated and happier. “The different neurotransmitters and hormones released during the experience could explain that,” she says. Or, by voluntarily choosing to endure a scary or stressful activity—whether it’s watching a freaky movie or bungee jumping—you’re likely to experience a feel-good sense of accomplishment afterward.

But—and this is a big caveat—Kerr says her research only included people who wanted to partake in the scary experience. For those who don’t get a thrill out of a horror movie or who don’t enjoy being scared, there may not be any mood or anxiety benefits.

Some frightening movies or experiences may be too much for kids in particular. An older study from the University of Michigan found that 26% of college students who had experienced a media-based scare during childhood still had “residual anxiety” from the experience.

So wait until the kids are in bed before firing up the next horror flick in your Netflix queue. Based on the existing science, you may burn some calories and boost your mood.

Keyword Mind & Body - Health.com , mind-body