When people think about intense, fat-burning workouts, most people think of heat. But thanks to a little-known type of fat that humans carry, the opposite may actually be true. It's called brown fat.
Brown fat is located up in the shoulders, the back and the chest. It's called "brown" because under a microscope, the cells are filled with iron-laden energy packs called mitochondria. As it burns, the cells generate heat.
Dr. Aaron Cypess, National Institute of Health researcher, compares brown fat to firewood.
“The wood is in the fireplace and that's the brown fat, and then you have to activate the brown fat to get the energy being consumed. So that's where you're lighting the fire," he said.
Along with warming people up, some studies suggest brown fat may help lower blood sugar and improve insulin function.
"People with type 2 diabetes that were exposed to the mild cold, there was an improvement in their glucose profile, and this makes us very excited," Cypess said.
Another way to switch on brown fat is exercise. Some believe that dialing down the thermostat during a workout can boost the benefit.
University of California Irvine associate professor Wayne Hayes created his own way of activating brown fat. The Cold Shoulder is a vest that is loaded with ice packs. Hayes claims the extra chill has a major effect on burning calories.
"I do have some informal trials I've done with fitness fanatics. Their results are pretty uniform and the vest does result in burning about a pound of fat per week, but that's not under tightly controlled conditions," Hayes said.
Hayes suggests wearing The Cold Shoulder twice a day for 60 to 90 minutes. There's a classic and pro version of the vest that sell for $200 and $150.
To find out more about the product, click here.