Why Scary Movies Make Your Heart Pound and Muscles Clench

Dr. Regis Fernandes, a cardiologist at Mayo Clinic, breaks down what is happening in your body — and the reasons why — when you watch a scary movie.

We here at In the Loop HQ are fans of all things fall. Football. Pumpkin spice. The onslaught of scary movies that show up in theaters in the weeks before Halloween. (We're talking to you, It Chapter Two and Downton Abbey.)

We're also a curious bunch. How is it possible for a movie to make our hearts pound like we've been running from Jason Voorhees?

Turns out we aren't the only ones wondering. Our friends at Mayo Clinic News Network put the question to Regis Fernandes, M.D., a cardiologist at Mayo Clinic. Dr. Fernandes breaks it down like this: "What happens to the human body when you watch a scary movie … comes from the known fight or flight response. When we are being chased by an animal, our instinct is to either fight the animal or flight, which means to run away." Dr. Fernandes tells BuzzFeed News that the fight or flight response "can also be activated with anxiety — so the danger might not exist, but your mind creates the same feeling."

That feeling can push your heart rate up to rates equivalent to mild-to-moderate-intensity exercise. You might even breathe faster and sweat a bit, BuzzFeed notes. (They also helpfully point out that "this doesn't mean watching a scary movie is equivalent to exercising." Harrumph.)

While you won't get credit for a workout for watching something scary, it's also probably not bad for your health. That said, Dr. Fernandes tells BuzzFeed "if people have a tendency to not tolerate a high heart rate or blood pressure, then yes, this fight or flight response may not be healthy for them." If that sounds like you, talk to your health care provider before pushing play on anything too scary.

A racing heart isn't the only way your body responds to scary stuff on a screen. Ever notice that during spooky scenes you "clench your limbs against your body, curl into a ball, and grip the armrests or hold a blanket in front of your face so hard your knuckles turn white?" That's muscle tension, and it's another way your body prepares to do battle with baddies. "Fear can cause your muscles to contract and tense up because this part of your body is preparing for a reaction," Dr. Fernandes tells BuzzFeed. "Once the scary scene is over, your muscles will relax again."

And if movies don't do it for you, here's another way to get a scare this Halloween.

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