I Watched American Horror Story's Scariest Bits While Hooked Up to a Pulse Monitor to See How Terrified I Really Was

It's the Monday before Halloween and I'm ascending a dimly-lit staircase above a Shoreditch pub. I'm here for a private screening of American Horror Story: Freak Show.

This is a screening with a difference. Tonight, I'm going to be watching the scariest bits from American Horror Story's fourth season while hooked up to a heart rate monitor. By tracking the effect it has on my pulse, I'm going to find out exactly how scary the show really is.

I'd be lying if I didn't say I was apprehensive. I'm not great with scary stuff at the best of times – I'm definitely a "check under the bed and sleep with the lights on after watching a scary movie" kind of girl. So how will I fare watching all the jumpiest, bloodiest, edge-of-your-seat moments from Freak Show on a dark October night? "Nah, it'll be fine," I tell myself, wondering what I've signed up for.

The trailer for 'American Horror Story: Freak Show'

I walk into a haunted horror house-themed room and gratefully accept a Halloween-themed cocktail to steady my nerves. A Sony Smartband 2 is strapped to my wrist, synced to a Sony Xperia Z5 Compact. We measure my resting pulse – it's a low 54 beats per minute. We'll take it afterwards, to track how much it increases after watching the show.

It's time for me to take my seat for the screening. We dim the lights and it begins. A picture-perfect American soccer couple picnic in a gorgeous, Technicolor field. I know instantly something awful is going to happen to them – they're too good-looking to live. Right on cue, a menacing figure looms large from across the field. I shift uncomfortably in my seat. The evil clown plunges an enormous pair of kitchen scissors into the man's chest. I laugh nervously at the red ribbons of arterial spray. This is scarier than I expected.

American Horror Story: Freak Show takes place in the quiet town of Jupiter, Florida, following a struggling freak show as it sets up shop in the sleepy town. As I watch the season's scariest bits I can't help but thinking that, in amongst the blood and gore, there are moments of humour – showing the influence of the show's co-creators, Ryan Murphy and Brad Falchuk, the brains behind comedic hit Glee.

I'm surprised by how genuinely scary the show is – properly scary, not "lights coming on in a nightclub and you see the face of the person you've been kissing" scary. One scene in particular – where we watch a dim-witted employee track a trail of blood through an abandoned toyshop – hardened my resolve to do all my toy shopping online from now on.

With that, the screening ended and the lights came on. It was time to check my pulse. I knew it would have gone up – my palms were clammy – and indeed it had. It was 54BPM pre-screening, and post toy-shop-bloodbath I was beating at 72BPM – an increase of 33 percent.

Worried that I was the biggest wimp there, I asked about everyone else watching Freak Show's scariest bits: what was the average heart rate increase? Pleasingly, it turns I'm not totally pathetic – the average heart rate increase was 33 percent, making it much more panic-inducing than your average night at the multiplex.

What did I learn from my night at the Freak Show? Well, that I'm not a total wimp, after all. That American Horror Story: Freak Show is pretty scary. But mostly, that if you see an angry clown approaching you with a pair of scissors, you should definitely run.

American Horror Story: Freak Show is out on Blu-ray and DVD now.