This summer, it’s hot to be cold. By which we mean, in-the-know wellness folks (like Jennifer Aniston and Jessica Alba) are all in on whole-body cryotherapy. What's cryotherapy? Why, it's when you stand naked in a giant tube that's chilled to -270 degrees Fahrenheit, of course. It originated in Japan in the 1970s to treat patients with arthritis, and proponents say it reduces inflammation, boosts circulation, increases energy and helps with weight-loss. Research says the weight loss claims are bogus, but some studies have shown that standing in a freezing cold chamber for three minutes can help you recover faster, perform better and relieve pain related to osteoarthritis.