Brr! If you live in the Northern Hemisphere, the winter cold is gone for good–but research recently published in the journal Diabetes says you might want to experience those blistery chills once more. Presenting their findings at the International Society of Endocrinology and the Endocrine Society in Chicago, they say that brown fat, a type of fat that burns energy and glucose, grows even faster in cold environments, raising a person’s metabolism.
In the past, research found that brown fat helped people stay lean and have lower blood sugar levels–though researchers weren’t sure why this was the case.
“The improvement in insulin sensitivity accompanying brown fat gain may open new avenues in the treatment of impaired glucose metabolism in the future,” says Dr. Paul Lee, a former research fellow at the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health, who led the study. “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.”
To figure out how brown fat specifically interacted with a person’s metabolism, Lee and his team recruited five men between the ages of 19 to 23 years to track their basal temperature throughout the day–from when they got up to when they fell asleep.
For a total of 4 months, researchers allowed them to participate in their normal activities but required them to sleep in a special room where researchers could control the temperature. It was there that researchers tested how their brown fat stores responded to certain environmental temperatures. First, they set the temperature at 24C, then lowered and raised it from 19C to 27C.
Throughout this process, they tracked their brown fat stores with CT scans, and then compared these amounts to the amounts they had before testing after the study. What they found was that being exposed to mildly cold temperatures–such as 19C–caused brown fat activity to increase by up to 40 percent.
“[Increases in brown fat were] accompanied by improvement in insulin sensitivity and energy burning rate after food,” says Lee. “Studies in both the UK and US measuring household temperatures in individual homes during the last few decades have shown that the temperature has climbed from around 19º C to around 22º C, which is a range sufficient to quieten down brown fat.”
In addition, Lee hypothesizes that the rise in environmental temperatures inside the home may cause people to have less brown fat–and in turn, have slower metabolisms. This, in turn, could mean something as simple as the temperature in your home could be making you fatter.
“So in addition to unhealthy diet and physical inactivity, it is tempting to speculate that the subtle shift in temperature exposure could be a contributing factor to the rise in obesity,” says Lee.
What You Should Do
While health experts are still mum on these findings, there are certainly no health risks associated with slightly lowering the temperature on your home’s thermostat. So don’t be afraid–bump down your thermostat by a few degrees. The change may seem insignificant, but according to Lee’s findings, could make a big difference in the speed of your metabolism.
Readers: What other tricks do you use to speed up your metabolism?