Cold air may help lose weight

A previous study from researchers in Japan revealed a decrease in body fat after people spent 2 hours per day at 17 degrees Celsius for six weeks.

The new study also found that people get used to the cold over time. After six hours a day in the cold for a period of 10 days, people in the study increased heat-generating, calorie-burning brown fat, felt more comfortable and shivered less at 15 degree Celsius.

At least in young and middle-aged people, non-shivering heat production can account for a few percent up to 30 percent of the body's energy budget, they said. That means lower temperatures can significantly affect the amount of energy a person expends overall.

So perhaps, in addition to our exercise training, people need to train ourselves to spend more time in the cold, the researchers said.

Managing that in practice, however, might take some convincing. "Indoor temperature in most buildings is regulated to minimize the percentage of people dissatisfied," the researchers wrote.

"This results in relatively high indoor temperatures in wintertime. This is evident in offices, in dwellings and is most pronounced in care centers and hospitals. By lack of exposure to a varied ambient temperature, whole populations may be prone to develop diseases like obesity. In addition, people become vulnerable to sudden changes in ambient temperature."