Horror movies may not have the year-round box office appeal of big-action blockbusters. But, as well as having a seasonal Halloween appeal, they’re the type of films we tend to remember most, and stay with us for days, weeks or even years afterwards.

Watching a horror film can also have a significant, albeit temporary effect on how our bodies function; and with halloween just around the corner, we thought it would be interesting to take a look at these effects in more detail.

So, with the help of clinical lead Dr Daniel Atkinson, we’ve put together our own timeline, explaining what the body goes through during a horror film experience at the cinema:

  • Pre-film

The pre-film aspects of a trip to the cinema to see a horror movie can be quite relaxing and pleasant. It’s time to select your favourite drink and snack whilst catching up with friends. Your heart rate will be steady and you might feel excited about what lies ahead.

  • 0-20 minutes (1st act)

As the story builds your body might begin to show signs of mild anxiety as it anticipates something bad happening.

A horror film that follows a conventional narrative structure will set the audience’s heart racing within the first ten minutes or so. A scary scene will cause a sudden spike in fear, and set the tone so that the audience is kept on edge throughout the duration of the film.

In response, the body’s sympathetic nervous system will increase the levels of cortisol and adrenaline being pumped around the body. The ‘fight or flight’ hormones prepare the body for extreme circumstances, in case it might have to react in a moment’s notice.

Pulse and respiration rate will increase to make sure that the body is prepared for action, whether that be running away or staying and fighting.

Pupils will dilate to increase sensitivity and broaden vision so that any potential threats can be easily identified.

  • 20-70 mins (2nd act)

The narrative will then aim to create rises and slumps in anxiety and anticipation as each scene is played out.

Lots of mini spikes in fear will be activated, as the film uses various techniques, such as false jump scares. This storytelling method will lead you to believe you’re about to encounter something truly terrifying and at the last minute it turns out to be something very normal instead (but then followed up very quickly by something actually scary).

You may experience palmar hyperhidrosis, more commonly known as sweaty hands, another process triggered by the sympathetic nervous system. The palms of our hands contain lots of eccrine sweat glands which are activated when we get scared.

  • 70-90 minutes (3rd act)

The climax of the movie will likely leave you noticing your heart pumping hard in your chest, you may even feel palpitations. During the aforementioned ‘fight or flight’ reaction the blood rushes away from the gut and instead heads towards the essential organs (brain and heart) resulting in the feeling of palpitations.

As the scare factor ramps up, you might notice other reactions such as your hair standing on end, also known as goosebumps or piloerection. Thought to be linked to our ancestral animal instincts, our hairs stand on end when we are in a dangerous situation.

Once the film concludes the audience will feel an immense sense of relief. You may have even held your breath at crucial points and so take a large intake of oxygen

  • Post-film

It should only take a short while for the body to reacclimatise, as the brain is able to quickly distinguish between what is real and what is not. Therefore a normal heart rate should be reestablished fairly quickly.

All of the processes listed above can potentially burn energy and leave members of the audience feeling a little fatigued later on. However, if you’ve been snacking on sugary or salty treats you might not feel these effects straight away.

Traditional cinema snacks tend to be either high in sugar or high in salt. A gripping scary storyline might mean that you are more likely to mindlessly eat a greater amount of your chosen snacks than you usually would. The caffeine and sugar found in some fizzy drinks and snacks could leave you feeling agitated and jumpy. This combination could also contribute to a poor night’s sleep.

The terrifying content that fills horror movies may infiltrate our dreams, and occasionally this can keep us from getting a good night’s sleep. Therefore the effects of a horror movie may be more far reaching than initially thought.

However, we aren’t by any means advising against them. Watching horror films can be a memorable, exhilarating and fun experience; and a great social occasion to enjoy with friends. And there are few things quite as atmospheric as enjoying a horror film at Halloween. But keeping an eye on your sugar and snack consumption while enjoying it, as always, is a good idea.

The pleasure/fear connection

Why do some people enjoy the feeling of being scared more than others?

The answer to this is not exactly known, as it potentially lies within the depths of our own personalities. The parts of the brain triggered by fear and pleasure are thought to be closely linked, and this may be why some people enjoy the thrill of feeling scared when watching a film more than others.