http://comment.independent.co.uk/columnists_a_l/alex_james/article2281964.ece

The principle behind cryotherapy is that, exposed to the extreme cold,
the 250,000 temperature receptors in the skin send a message to the
brain that say something like "wow", and that a healthy body reacts
well to that stimulation. It's a beneficial effect similar to training
in a hypoxic (low oxygen) chamber, or at altitude; the body learns how
to process oxygen better and becomes more efficient.

Many of the other understood benefits of this exposure to ultra-low
temperatures are similar to the benefits of exercise: an improved
ability to focus and enhanced libido are just two of them. It's also
an autoimmune tuning, skin rejuvenating, cellulite busting, sleep
adjusting panacea. I'm always sceptical about anything that makes this
many claims. On the other hand, Charlie looks very fit indeed.

notice that the indicated temperature has fallen to minus 117C.
Charlie says that's nothing. I feel nervous. Next we enter an icy
foyer, which is at minus 50C or so. If the door of the really cold
room were opened directly on to the ambient conditions, the
temperature and humidity in there would rocket, so entry is a
two-stage process.
The chamber, which is about the size of a standard steam-room, holds
up to four people. Any more and it gets too damp. The four of us
bundle in.

How cold does that cold feel? Well, it's all relative. It feels much
colder and more uncomfortable if I crouch down near the floor.
Standing up straight again, I feel (relatively) rather warm and
well-off. We clop and skip around in a circle. Standing still doesn't
feel right at all. I shift my weight from foot to foot. Claire and
Charlie are howling and laughing. Charlie announces that he's already
done three minutes in here today. "Three minutes!" I say: "How long
have we been in here?" "Fifteen seconds!" comes his deadpan reply.

we begin a workout on the VibroGym - a throbbing, wobbling plate that
triggers muscle reflexes while you exercise, slashing workout times by
three-quarters. It appears to be irresistible to women.

Claire has already been won over by these power plates. Our neighbours
have just bought one, and she uses it regularly. Standing, sitting or
lying on the vibrating plate causes muscles to contract and release
many times per second, in resonance with the oscillations. It's
intense; so intense that 20 minutes on one is a thorough session.