Forget the chill that seeps into your bones as you wait for a bus. When the mercury has plunged to -130C, a couple of numb toes would almost come as a relief. As I walk into a chamber colder than any deep freeze, the shock to my system feels like the tiny pins and needles of a belly flop spreading all over every exposed inch of my flesh.
I've been told to move around to increase the flow of blood – and to roll out my shoulders to help resist the urge to clench every muscle in my body – but all I can resist is the urge to scream as I'm racked by a series of exaggerated shivers.
Through chattering teeth, I mouth a silent curse to Tony Blair, whose icy footsteps I have followed to a health spa in Hertfordshire.
We learnt this week that the perma-tanned former Prime Minister likes nothing more than to escape the heat of the Chilcot Enquiry and the Middle East, where he is a UN peace envoy, by chilling out in the kriotherapy chamber here at Champneys Tring not, far from Luton.
Blair reportedly started undergoing the bizarre treatment after an operation on his knee last year. His wife, Cherie, who recommended it, gamely joined her husband occasionally, and apparently could be heard singing "Always look on the bright side of life" as a way to distract herself from the bitter cold.
Renata, the bubbly Polish therapist who is now torturing me won't discuss her clients – or confirm reports that Blair was here on Saturday – preferring instead to explain why anybody would want to submit to such treatment in the first place.
Originating in Japan in the 1880s kriotherapy, or cryotherapy, in its modern form was introduced with the invention of the cryogenic therapy chamber in 1972. Polish research into the effects of sub-zero conditions on the body showed that as the blood rushes from the extremities to help warm the internal organs, the accompanying release of endorphins results, perhaps unsurprisingly, in an analgesic or numbing effect that eases pain in people with injuries.
Renata tells me that in Poland it is such a well recognised treatment that it is prescribed on their national health system as part of physical therapy for those who have undergone surgery. The illustrious clientele of Champneys Tring seem to testify to the treatment's success. The chilly smiles of champion jockey Tony McCoy, world class skier Chemmy Alcott and numerous premiership footballers and racing drivers beam down from the walls.
I'm no more likely to take part in the kinds of activities – sport, for example – that would result in an injury than I am to stick my head in a fridge, but, intrigued enough to try, I've agreed to shed my dignity and wear a double-layered fleece crop top and shorts combination accessorised with knee socks and gloves.
I've been instructed not to wear any moisturiser or perfume and to ensure my skin is completely dry I'm stuck in front of a fan for a few minutes. The merest hint of water must be removed so that it doesn't freeze in the chamber and cause an iceburn with a similar level of pain and redness to sunburn. Anything more than that and we're talking frostbite.
Before the real freeze, I'm led into a relatively balmy chamber (balmy as in -60). The theory is that by standing in here for 30 seconds I'll become acclimatised. Wooden clogs protect my feet from the floor which is about 20 degrees colder than the rest of the room. Half a minute feels like an eternity. According to Einstein's theory of relativity time is fluid, well in here it appears to be more like frozen slush.
But that's nothing – I now have to face three minutes at a breath-taking -130. Cold doesn't cover it. How Cherie managed to sing anything in these conditions is beyond me – it's as if ice has bridged my synapses.
Time passes even more slowly as I clatter around on my clogs. After what feels like way more than three minutes – but is, I later learn, 2min 40secs, I try to give the agreed "time out" signal to indicate that I've had enough. But because my gloved fists are clenched in what feels like blocks of ice, all I can mange is to claw at the window.
Leaving the chamber feels like entering a sauna. The room floods with dry ice as the liquid nitrogen-cooled air meets the moisture in the room. I take off the clogs and keep moving to help get the blood, which has flowed to my heart and internal organs, back to my skin, which is pinking up through a cover of goose pimples.
Off come the bandages and mask, which I'd been given to help stop the inside of my mouth freezing, and I am taken through a series of stretching exercises on a VibroGym, a platform that increases muscle strength by vibrating. As I start to feel human again, Renata tells me Tony McCoy would come for treatment two times a day, with exercise in between. Good for him, he's obviously made of sterner stuff than I. I will never again complain about feeling cold.