Exposing your body to temperatures of -110C can be an excellent tonic.

During the so-called Big Freeze that paralysed parts of the country last week, night-time lows reached -9C. Pah! I'm about to experience temperatures more than 100C lower than that - and while wearing little more than a swimsuit.

The reason? Because chilling out in an oversized deep-freeze - or cryotherapy as it is known to spa-goers - is an extreme pick-me-up. More than that, it is said to work wonders for the skin, can boost your immune response, ease chronic pain, heal nerve damage, and even improve sporting performance.

Whoever thought that walking half-naked into a sealed, icy chamber with a pair of knee-high socks, gloves and ski mask could be good for you? The Japanese, as it happens, who came up with the idea of "whole-body cryotherapy" in the 1970s. But it was Polish scientists who embraced it as a way to relieve chronic pain, helping to popularise it in sanatoriums across eastern Europe.

Whole-body cryotherapy is currently only available in one UK resort - Champney's in Tring - but devotees say that the massive hormone rush from the freezing temperatures can benefit anyone suffering from stress, burn-out, insomnia or depression. It's good for skin conditions like psoriasis. It is also an effective analgesia; your body is so busy focusing on the cold, it forgets everything else.

As well as easing the effects of arthritis, rheumatism and multiple sclerosis, it has been shown to boost sporting performance; the Olympic rehabilitation centre in Spala, Poland, has a cryotherapy chamber used by sports teams from around the world. Many athletes record a remarkable 10 per cent improvement in performance after a dip in the deep freeze. Jockey Tony McCoy used it a couple of years ago to recover from serious back injury in time for Cheltenham, and the Irish rugby team have been enduring cryotherapy sessions for almost a decade, believing it to limit muscle damage and as an aid to recovery.

Perhaps inevitably, cryotherapy is building something of a celebrity following, too. Saffron Aldridge, Susanna Constantine and Normandy Keith have all been in Champney's cryotherapy chamber. Prior to Take That's most recent tour, Jason Orange reportedly had sessions to rid him of a dancing injury.

"When you step inside the chamber, the shock of cold will make your body release advanced levels of adrenalin and endorphins," explains Dr Georg Kettenhuber, resident doctor at Alpenmed Lamm, a smart European spa in the Austrian Alps and the latest to add state-of-the-art cryotherapy to its list of treatments. "You boost blood circulation which increases the delivery of oxygen and nutrients and speeds up the removal of toxins."

Image
The Wales rugby team emerge from another cryotherapy session
All of which appealed when I signed up to try it out. Not far off 40 and a mother-of-three, I haven't had a full night's sleep since the birth of our first child nine years ago. I'm permanently tired (who isn't?) and (oh, the shame) exercise is one of those worlds I've yet to visit.

Cryotherapy appealed as an extreme measure - it's so terrifying, it must surely do something. And as sessions last a maximum of three minutes (any longer than eight minutes in the -110C chamber and you'd be dead), it must also be the fastest health kick available.

Yet, when the time comes to venture into the first, not-that-cold chamber, I'm truly terrified. Having removed all jewellery (to avoid certain frostbite), pulled on a pair of special trainers (if you slip over during cryotherapy, you'll stick to the floor), and selected a soundtrack (I opt for Michael Jackson's Thriller), I say goodbye to Dr Kuttenhuber and heave open the door.

The first two chambers - the first set at -10C, the second at -60C - serve merely to acclimatise you for the main event. My first feeling when I get inside the chamber chilled to -110C is relief. It's deeply freezing - my arms sting instantaneously - but somehow it's bearable. It's unlike any cold I've ever experienced. It feels nothing like weather. There's no wind, no moisture. It's easier to bear than a cold shower.

All the while, Dr Kettenhuber is watching me through the windows and in close-up on a monitor. He counts me down and speaks encouraging words through a speaker while Michael Jackson sings through another. I'm aware that I'm acting like a headless chicken, jigging and jogging in circles, then changing direction (you have to keep moving or - you've guessed it - you'll freeze to the spot).

After just two minutes 40 seconds, I'm heading for the door, struggling because it's heavy and trying to quell my panic.

Outside, in the wonderful warm, I feel euphoric - which could be my adrenalin and endorphins pumping, or equally sheer gratitude for being alive and relief that it's over. Oddly though, the experience is addictive. The next morning, I'm looking forward to doing it again. By my third stint, I manage to last the full three minutes.

After the three sessions, my skin has a rosy glow and I feel noticeably energised. I also sleep deeply for the first time in years, and find myself doing strange things, like rising at 7.30am for water gymnastics and forging ahead on a morning of Alpine walking. I also feel permanently warm, even up mountains, like the Ready Brek kid. It's as if my own inner central heating system has been kicked into action.

Dr Anthony Soyer, from the Diagnostic Clinic in London, is not surprised. "There are lots of historical precedents," he says. "Cryotherapy originated in Japan where there's a long tradition of cold therapy to boost your immunity in winter. One form involves standing under waterfalls. In China, there's a belief that your system stagnates if you don't wake yourself up, give yourself a shock. Cold is a very effective way of doing it."

And, even in the current chilly climate, you can't say cooler than cryotherapy.

Þ Cryotherapy sessions cost £26 at the AlpenMedHotel Lamm (Seefeld, Austria, 0043 5212 2464, www.alpenmedhotel.com), with rooms from £82 per person. EasyJet flies to nearby Innsbruck from London Gatwick, from £44 return.

Where else to go to feel the deep freeze:

CHAMPNEYS, Tring

Two-chamber cryotherapy suite, with a deep freeze that goes down to -135C. Sessions, which include a 50-minute 're-warm' in the Vibrogym, from £50.

Details: 08703 300 300; www.champneys.com

WHITES OF WEXFORD, Ireland

Ireland's first cryotherapy clinic, with three cold chambers from -10C to -110C. London Irish block-booked the suite last week. Recommended three sessions per day, from €135 (€105 for hotel guests). Rooms from €49 B&B, and from €175 B&B including dinner for two at weekends.

Details: 00353 53 912 2311; www.whitesofwexford.ie

AQUACITY, Slovakia

Geothermal waterpark in north east Slovakia where cryotherapy treatments cost around €15 (€59 for five sessions). A four-night stay from £356 per person.

Details: Europe Getaway (0845 270 3800, www.europetravelservices.co.uk) SkyEurope (www.skyeurope.com) flies to Poprad from London Luton from £130 return.