Cryotherapy: Why people are now choosing to "freeze" their skin.

While we shiver through winter down here in the southern hemisphere, Lindsay Lohan has been willingly submitting her body to sub-zero temperatures… wearing nothing but swimmers, gloves and a headband.

On Instagram yesterday, the Mean Girls star was pictured “crying laughing” as she emerged from an ice lab in New York. She’s not alone in this behaviour — back in February, actress Mandy Moore shared snaps of her own chilly experience.

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It sounds like just another kooky celebrity hobby, but it’s the modern form of a medical treatment that’s been around since the 17th century. Known as whole-body cryotherapy, it involves standing in a chamber filled with freezing, dry nitrogen gas chilled as low as -170 degrees Celsius, with only your extremities sufficiently covered.

The therapy lasts just three or four minutes, because any longer than that would put you in a bit of trouble. Initially, cryotherapy was used in medieval Europe to treat inflammation diseases like rheumatoid arthritis; it’s still used for medical purposes.

We’re not sure exactly why Lohan and Moore chose to have cryotherapy, but it’s been linked to number of general health, beauty and even mental benefits. (Post continues after gallery.)

According to Inc. cryotherapists claim the extreme temperature switches on the body’s “fight or flight” survival response, causing it to direct blood flow to the vital organs and pump the bloodstream with oxygen and nutrients.

This is said to have positive effects on the body: a reduction in muscle soreness, inflammation of the joints and fatigue; growth of healthy skin cells; and the production of mood-boosting endorphins, which help to combat stress and improve energy.

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Whole-body cryotherapy appears increasingly popular among athletes around the world, including here in Australia, to help them overcome fatigue and recover from injury.

Football star Cristiano Ronaldo purchased a chamber for his home in 2013, while Australian F1 driver Mark Webber used the therapy after breaking his leg. The therapy isn't dissimilar to ice baths, another popular technique in the sports world.

For other celebrities, the appeal of cryotherapy is more aesthetic. According to Beauty World News, Jessica Alba and Demi Moore have used it for their skin — supposedly it can make the skin appear younger, and also help with conditions like acne and psoriasis.

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However, dermatologist Dr Mike Comins told the Daily Mail any dermatological benefits are likely to be short-lived.

"When exposed to cold temperatures, the blood vessels constrict to help maintain body temperature. When you warm up, they dilate and blood rushes to the skin’s surface, giving the ­complexion a temporary glow," he explained. (Post continues after gallery.)

Whole-body cryotherapy is still quite rare here in Australia, so perhaps just spend a little more time hanging around the frozen food aisle of your local supermarket to get similar benefits for free. (Just kidding...)

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We're not sure about you, but we think we'll give this treatment a miss — especially after reading that American sprinter Justin Gatlin suffered frostbite on his feet after going into a cryotherapy chamber with slightly damp socks. Ow.

Have you ever tried cryotherapy? What was it like?