One of the hottest trends in therapy right now is tricking your body into thinking it's dying.

I'm talking about cryotherapy — a procedure that involves standing in a chamber of up to -90 degrees Celsius for a couple of minutes (because any longer would literally kill you). It produces a fight-or flight response in the body, and a huge rush of endorphins. The unconventional treatment is beloved by athletes and celebrities alike.

(Claudia Romeo/BI (Claudia Romeo/BI)

I wanted to see what the fuss is about, so I paid a visit to a London clinic to try it for myself.

For my cryotherapy session, I visited 111Cryo in Knightsbridge, London. It's inside high-end department store Harvey Nichols. Full disclosure: 111Cryo provided the session free-of-charge. A single session would normally cost £95.

(Claudia Romeo/BI (Claudia Romeo/BI)

It bears more than a passing resemblance to Mr. Freeze's lair. -90 C would be bad enough in a heavy overcoat and thermals. But you do cryotherapy almost naked, with only some thin fabric protecting you. On the plus side, you do get some rad North Face booties to wear.

(Claudia Romeo/BI (Claudia Romeo/BI)

After getting briefed on what to expect, I was ready to go in. While stylish, the main purpose of the headband was to make sure my ears didn't freeze off.

I've experienced low temperatures before. I once worked at an ice sculptor's, which involved cleaning ice off the floor of a -20C store room. That was pretty chilly. But this was something else. It was unbearably cold. Every hair on my body was covered in a crystalline coating of ice.

(Claudia Romeo/BI (Claudia Romeo/BI)

And while I had a personal trainer on the outside shouting encouragement, I couldn't hear a thing — meaning I had no idea how long was left. Did a two-finger gesture mean there were two minutes gone, or remaining, or just a peace sign?

(Claudia Romeo/BI (Claudia Romeo/BI)

By the end of the three-minute session, I was shaking uncontrollably. So ... why do it? 111Cryo says its treatment has a range of benefits, from improving muscle recovery for sports conditioning, to helping with skin conditions, as well as offering pain relief — and even helping with weight loss by boosting the body's metabolic rate.

The reality is a little murkier. "This so-called 'treatment' hasn’t been proven to do any of these things," the US Food and Drink Administration says on its website. In other words, there's little scientific evidence for what its proponents claim. However, that hasn't stopped high-profile users flocking to it. "If you look at the top five paid athletes in the world, all use cryotherapy on a regular basis,” 111Cryo managing director Daniel Smith told me. Everyone from LeBron James to Cristiano Ronaldo have given it a go.

(Claudia Romeo/BI (Claudia Romeo/BI)

As an experience, it was pretty wild. I'm glad I did it, in a slightly masochistic way. It was brutally cold, but I definitely felt energised and awake when I came out. (Plus, it makes a good story.) Within a few minutes, however, it was back to normal.

It doesn't come cheap though, at £95 for a one-off session — especially given they recommend you come eight to ten times to make the most of it. That said, the kind of people who the luxury treatment advertises itself towards are unlikely to be put off by the price tag.

Ultimately, since visiting 111Cryo a few months ago, I haven't felt the urge to go back. The benefits are hazy, and it's an awful lot of money for three-minutes for subzero discomfort.

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