Changing Seasons also 'Change' your Metabolism

Keeping cool and out of hot weather is fun and easy, but there's also a bit of science to the whole thing, as well. Staying out of warm, sticky environments can actually promote the growth of brown adipose tissue--otherwise known as the fat that burns energy that's used to generate heat. The findings, published in the journal Diabetes, were recently presented at the International Society of Endocrinology and the Endocrine Society in Chicago.

"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 Endocrinologist Dr. Paul Lee from Sydney's Garvan Institute of Medical Research, in a news release.

As brown fat found in animals can help protect them from diabetes and even obesity, its regulation in people is still relatively unclear regarding metabolism.

However, scientists may have discovered a few things. For their study, they recruited five healthy men and exposed them to four month-long periods of defined temperature. Throughout their normal daily lives, they were also required to go to the NIH Clinic Center and spend 10 hours in a temperature-regulated room

For the first month of the study, the rooms were maintained at 24 degrees Celsius which is a "thermo-neutral" temperature. However, the temperature was then moved back to 19 degrees and then back to 24 degrees during the third study month. At the fourth month, it was moved to 27 degrees. 

"What we found was that the cold month increased brown fat by around 30-40%. 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."

Researchers believe that these findings could hold critical information regarding new treatments for those with diabetes who cannot properly lower blood sugar levels following a meal.

"The improvement in insulin sensitivity accompanying brown fat gain may open new avenues in the treatment of impaired glucose metabolism in the future. On the other hand, the reduction in mild cold exposure from widespread central heating in contemporary society may impair brown fat function and may be a hidden contributor to obesity and metabolic disorders," Lee said. "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."