- Golfer Padraig Harrington uses cryotherapy as part of his fitness regime
- The deep-freeze treatment is increasingly popular with professional athletes
- Athletes enter a chamber that is chilled to -130 degrees Celsius (-200 ˚F)
- New York salon owner says cryotherapy creates such a high it's like "legal doping"
(CNN)Would you dare to freeze yourself fit by stepping into a chilling chamber colder than Antarctica?
Golfers are used to frosty fairways, stormy tees and soggy greens but Padraig Harrington is taking the plunge with a real deep freeze.
Ireland's three-time major winner is following in the chilling footsteps of actor Daniel Craig and super-fit soccer star Cristiano Ronaldo by exposing himself to cryotherapy in preparation for the 2015 season.
"I've used whole body cryotherapy for several years," Harrington commented to CNN.
"Guided by research from Setanta College, it's played a key part in my recovery, especially between competitive periods."
Cryotherapy translates as cold cure -- but for some the intense chill goes beyond words.
"The cold floods your brain and you can't process much more than putting one foot in front of another," Mike Moynihan, a columnist for the Irish Examiner, recalls of his experience in the chiller.
"Your body is in revolt and won't allow you to relax. It's so different, to be that cold, that I had a real notion of what people mean when they refer to a hostile environment -- but that only came afterwards, when I was outside."
Chill with a thrill
For others, cryotherapy is an ecstatic chill with a thrill.
"I call it 'legal doping,' says Eduardo Bohorquez, who runs New York's only cryotherapy center. "When you come out you feel so euphoric."
Those brave enough to enter the cryotherapy chamber expose themselves to tingling temperatures of -130 degrees Celsius or -200 Fahrenheit.
That makes Antarctica -- where NASA recorded the coldest spot on earth as -92 degrees Celsius at the end of December 2013 -- officially warmer.
There are two types of cryotherapy treatments -- whole body and partial exposure -- but both involve serious sub-zero temperatures.
"It's not like sticking your hand in an ice bucket or taking an ice bath -- this is extreme cold," Liam Hennessy, Harrington's fitness coach and a world leading expert in cryotherapy, tells CNN.
"Whole body exposure is like stepping into a butcher's fridge. Partial exposure is more like entering a suntan cabin where the top of the head stays out of the cold.
"Padraig loves the challenge of taking whole body cryotherapy. He's a heavy worker.
"He has a huge practice and training regime. Part and parcel of the recovery process for him is cryotherapy."
The drafty drill sees Ireland's double British Open champion enter a TARDIS like chamber, which is cooled by liquid nitrogen to temperatures between -120 and -140 degrees Celsius.
He will then experience what's known as a "short exposure" which lasts for two to three minutes.
Cryotherapy was developed in 1978 by Toshima Yamauchi in Japan but is a relatively new treatment in professional sports medicine.
The Olympic Sports Center in the Polish village of Spala helped the treatment spread west.
Hennessy, in his role as director of fitness for the Irish Rugby Football Union, immersed his squad of international players in Spala's cryotherapy chamber in 2001.
The respected Irish coach claims they were the first sports team in the world to formally use the facilities.
Hennessy imported cryotherapy to Ireland and watched the freeze become a fashion. "It's now taken off big time in Wales, England and France and Germany," he adds. "The U.S. had no treatment centers in 2006 but now there are a couple of hundred."
But what are the effects of the big chill?
Cryotherapy has two main benefits for maxed out sporting stars -- helping speed up the body's recovery after intense training and promoting a deeper sleep.
"Part of our investigations included taking serum and blood tests to monitor enzymes related to muscle damage," explains Hennessy, who ran a research program into cryotherapy.
"What we saw is that they returned to normal when players took part in cryotherapy compared to when they didn't. It improved the inflammatory response, which led to a better recovery.
"We've also seen heart rate variability -- which is a marker of stress -- returned to the baseline quicker if the athlete is exposed to cryotherapy.
"We noticed that sleep quality is also improved straight away by an exposure to cryotherapy.
"Individual athletes would report, 'I just had a good, deep sleep and I feel very good.' It's also possible to get a quality of sleep number by attaching a monitor to the wrist."
In a four-year study of 156 rugby players, 95% said cryotherapy had a positive effect on their recovery after training.
"Many of those that take it will tell you afterwards that they feel elated, they feel a rush of energy and a high as happy hormones are released," adds Hennessey.
Traditional cryotherapy chambers, with three rooms of gradually dropping temperatures, are an expensive and unwieldy piece kit -- not the sort of thing you can pack on the team bus.
But cryotherapy has now gone mobile which means sports stars can order a deep freeze almost as easily as a hot takeaway.
"Having the unit on the road and available on a rental basis is opening cryotherapy up to an awful lot more people," Ian Bridge, managing director of cryotherapy consultants Sappari, tells CNN.
In 2013, Bridge conceived the first mobile full body cryotherapy unit in the UK, which is owned and operated by medical and industrial gases specialist BOC.
His clients include Premier League teams Bolton Wanderers and West Ham United as well as rugby union clubs such as Bath and Northampton.
"You can get a whole squad through the mobile unit in a day," Bridge explains "The British Lions rugby players used it before their tour of Australia last year and did three treatments a day.
"They were dragging the guys out of bed before breakfast sticking them through cryo, they'd do some gym work in the morning, then go in for another session before lunch, do some work on the pitch and then another treatment at the end of the day.
"The mobile unit is predominantly used to stimulate a quicker recovery after training or games."
It costs up to $1,500 to hire the six-meter long unit for a day in the deep freeze.
"We find our bookings come in around the Champions League fixtures," says Bridge. "It was in heavy use over the Christmas period because there was such a heavy football program."
Cryotherapy is not only the domain of fatigued footballers, its frosty fingers are also spreading to the high street.
The KryoLife center offers New Yorkers either a blast in its so-called "cryosauna" or a local treatment --increasingly used as part of a beauty regime to firm up skin -- where vaporized liquid nitrogen is blown over a specific part of the body.
"It is a growing industry," chairman Bohorquez, who brought cryotherapy to New York after receiving revelatory treatment in Poland on his injured right knee, tells CNN.
"There are a lot of famous people in the entertainment industry -- like actors Kevin Bacon and Ben Stiller -- and from the athletic world who use our center, so that has increased cryotherapy's popularity.
"Professional sports teams like the New York Knicks have a couple of machines which has also helped awareness."
You don't necessarily need a Hollywood salary to try cryotherapy -- it's probably cheaper than courtside Knicks tickets too -- because an icy blast in KryoLife's cryosauna costs $90.
If the price continues to drop, along with the temperatures, is there a chance that cryotherapy will become as normal as having a sports massage or a protein shake?
"Yes, I truly believe so," says Bohorquez. "Particularly the local treatment which is cheaper and less intimidating.
"I call cryotherapy legal doping because it boosts your energy levels and it makes your more alert. It increases your neuro-muscular response, so you react a little faster, and your immune system is activated.
"It boosts metabolism, which is also useful for weight loss, but it also stimulates your endocrine system so it relaxes you.
"I pretty much do it every day now," says Bohorquez cheerily. "You should try it."