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That's one way to lower body temperature.[/caption]
Since all AJ readers are elite athletes with 3 percent body fat, this story might not pertain to you, but perhaps you know someone who isn't quite so ripped who could benefit from it: Researchers have discovered that the human body can generate brown adipose tissue, a.k.a., brown fat, when exposed to cold.
Why should anyone care? Brown fat, say the study's authors, "is a special kind of fat that burns energy to generate heat. It keeps small animals and babies warm, and animals with abundant brown fat are protected from diabetes and obesity."
Or, as the New York Times put it more succinctly, "It burns calories like a furnace."
It's thought to be a kind of silver bullet for helping shed the less noble kind of fat that generates muffintops. Indeed, one of the more recent fitness fads has been "cold thermogenesis," or exposing yourself to lower temperatures in hopes of stimulating brown fat growth. It might sound like yet another ab blaster scam, but in fact the scientists at Australia's Garvan Institute of Medical Research found that it does just that.
In a four-month study, the Impact of Chronic Cold Exposure in Humans (ICEMAN) project recruited volunteers who spent every night in each of the four months in temperature-controlled conditions. The first month they spent nights at 75 degrees Fahrenheit, a level at which the body doesn't have to work to regulate its temperature. The second month was spent at 66 degrees, followed by another month at 75 and then the final month at 80 degrees.
"The big unknown until this study was whether or not we could actually manipulate brown fat to grow and shrink in a human being," said Dr. Paul Lee, the study's head.
"What we found was that the cold month increased brown fat by around 30-40 percent. During the second thermo-neutral month at 24 degrees, the brown fat dropped back, returning to baseline. When we put the temperature up to 27 degrees during the fourth month, the volume of brown fat fell to below that of baseline."
The researchers also found that brown far increases insulin sensitivity, opening possible avenues for helping people suffering from diabetics. One caveat of the study: They tested just five men.
If you, er, someone you know is trying to shed a few pounds, you might not have to get as extreme as wearing an ice vest. Simply lowering the thermostat could help.
"Studies have been performed in the UK and US measuring bedroom, dining room, and lounge room temperatures in people's homes over the last few decades, and the temperature has climbed from about 19 to 22, a range sufficient to quieten down brown fat," said Dr. Lee.
Photo by Escalapade/Flickr