It is something the Japanese learned from monkeys, but the man who introduced ganbanyoku to Auckland says it will also do wonders for Kiwis.
Ganbanyoku is a hot stone spa popular in Japan, where people spend all day in one - especially during the cold winter months.
No one knows its true origins, but Masa Sekikawa believes it was introduced to the Japanese by people who observed Japanese macaques sleeping on flat hot rocks after soaking in hotsprings in winter.
"These monkeys live long and healthy lives, so the early Japanese thought lying on hot rocks will be good for people too," said Mr Sekikawa, who brought the Japanese stone spa concept to Auckland in 2009.
Ganbanyoku is believed to have a detoxification effect similar to low-temperature saunas, and helps to improve the circulatory system and conditions the skin.
Stones are kept between 42C and 44C, with humidity between 62 and 65 per cent.
A visit to a ganbanyoku room usually follows a massage or a soak in a bath, and bathers lie clothed on the stones while their bodies gradually heat up.
"Although the spa goer will perspire more than they do in a sauna or steam bath, there is no odour, saltiness or stickiness," Mr Sekikawa said.
"Unlike the sauna, stone bed heats through your body evenly and gently and not through the skin."
He described ganbanyoku as "like bathing without water".
At the Auckland spa, on level four of the Atrium on Albert Street, each session lasts up to an hour, unlike in Japan where users can spend the whole day going in and out of one.
- Lincoln Tan
Bliss of lying on a hot stone
As the hot steam clouds the room, I'm thankful I didn't straighten my hair earlier, otherwise I'd look like a dandelion right now.
I'm lying face down on a hot stone slab only just covered by a couple of towels.
The room is dark and I'm almost drowning in the heat it's so overwhelming.
At first you wince as your skin touches the stone, but you soon adjust and it becomes less intense.
I'm at the Bliss Stone Spa at the Atrium on Elliott St, in central Auckland, and it's absolutely beautiful.
From the busy city streets you walk into a serene escape.
The walls are painted with rich colours - deep reds, browns and creams - with oriental-styled decorations.
I've been five minutes on the stone bed and already I'm drenched with sweat.
I'm told it's not the ordinary sweat you get from exercising - or doing hard work - and you're encouraged to not shower afterwards, for best results.
Unlike ordinary sweat, which is sticky and has an odour, this feels more as if someone has poured hot water over me.
As you lie on the stone bed, it gently heats you from the inside, spreading the heat around your body before releasing impurities and dead skin cells, leaving the skin glowing.
Sounds good to me. I'm in there for an hour, switching from my tummy to my back now and again.
I notice at the end of the session that the "sweat" disappears within minutes of leaving the spa room and my skin is not only dry but baby-bottom smooth.
The experience is soothing and relaxing and, with a traditional Chinese body massage and pedicure, would make a perfect day out with a couple of girlfriends or Mum.
Bliss Stone Spa, 4/F Atrium on Elliot, Auckland CBD
60 mins: $60
45 mins: $45
- Vaimoana Tapaleao
Tuesday: Greek leech therapy
Wednesday: Korean jjimjilbang
Thursday: Indian ayurveda
Friday: Thai yoga massage
Today: Japanese ganbanyoku