It’s 11 a.m. in the office, and I’m freezing. There are goosebumps on my arms as I clutch my coffee.

But who said burning calories was easy?

Meet the Cold Shoulder, a calorie-burning vest developed by NASA scientist Wayne B. Hayes. Though the vest hit the market in 2013, sales recently spiked. So, I decided to try this hot trend.

The back-ordered vest — which is available for $150 at coldsh.com — has pockets filled with six ice packs. The company claims you’ll burn an average of 250 calories per hour trying to stay warm.

As your body uses energy to heat up, it’s burning calories, too, so the vest works your system even harder. It’s a safer alternative to cryotherapy, in which you’re subjected to subzero temperatures in a chamber to burn calories.

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It takes up to eight hours to freeze the cold packs. When you strap on the vest, it warms up to a brisk 32 degrees.

Five minutes into wearing it, I catch a chill I can’t shake. An hour in, I’m ravenous like I’ve gone for a long run.

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