(HealthDay News) — Cooler indoor temperatures may stimulate the growth of healthy brown fat, while warm temperatures could cause the loss of this beneficial type of fat, according to a study published online June 22 in the journal Diabetes to coincide with presentation at the joint meeting of the International Society of Endocrinology and the Endocrine Society in Chicago.
The new study was led by Dr. Paul Lee, an endocrinologist at the Garvan Institute of Medical Research in Sydney. His team exposed five healthy men to different room temperatures over four months: 75 degrees Fahrenheit during the first month, 66 degrees during the second month, back to 75 degrees during the third month, and 80.5 degrees during the fourth month. The men performed normal activities during the day but returned at night to spend at ≥10 hours in the temperature-controlled setting.
The first month was used to determine the men’s starting amount of brown fat. Lee’s team found that those levels rose by 30–40% in the second (cool) month, returned to original levels in the third month, and then fell below those original levels in the fourth (warmest) month. The effect of indoor temperatures on brown fat was independent of outdoor temperatures, the researchers noted. The team also found that the men’s insulin sensitivity increased when they had greater amounts of brown fat.
“The improvement in insulin sensitivity accompanying brown fat gain may open new avenues in the treatment of impaired glucose metabolism in the future,” Lee said in an institute news release. “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.”