Unlike white fat cells that store calories for energy and expand as we gain weight, brown fat cells burn calories and generate heat to maintain body temperature. The trouble is, we don’t have many of them. If we had more of these metabolically active cells, we might be slimmer and healthier. A newly published study suggests that sleeping in a chilly room might boost our individual supplies of brown fat. This strategy worked in five healthy young men who agreed to sleep in climate-controlled chambers at the National Institutes of Health (NIH) for four months. By day, the men went about their normal lives and reported to NIH at 8 p.m. During the first month, bedroom temperatures were set at 75 degrees; the next month the thermostats were turned down to 66 degrees, which the researchers suspected could lead to a gain in brown fat. It worked: the volume of brown fat in the men’s bodies almost doubled. The bedroom temperatures were reset at 75 degrees for the third month and to 81 degrees for the fourth month in order to bring the men’s brown fat levels back to where they had been at the study’s start. Over time, tinkering with bedroom temperature could boost your brown fat stores, which might help lower your risk of diabetes and other metabolic problems and burn some extra calories, according to senior study author Francesco S. Celi. In this particular study, the temporary change was not enough to affect the weight of the men during the four weeks they slept in chilly room.
Francesco S. Celi et al “Temperature-acclimated brown adipose tissue modulates insulin sensitivity in humans.” Diabetes, June 22, 2014