Turning off the heat during the winter months may help dieters stay slim or lose weight, according to a new study that examines waist circumference in older adults.
The scientists behind the study say that the latest research, which links higher indoor temperatures to larger waists and lower indoor temperatures to slimmer waists, is important because waist circumference has been linked to hypertension, heart disease and diabetes.
Lead researcher Dr. Keigo Saeki and his team said that their findings may be explained by thermogenesis, which is when the body generates heat. Body heat generation in brown fat helps burn calories. Previous studies linked brown fat to higher metabolism and better blood sugar control.
"Although cold exposure may be a trigger of cardiovascular disease, our data suggest that safe and appropriate cold exposure may be an effective preventive measure against obesity," said Keigo Saeki of Nara Medical University School of Medicine Department of Community Health and Epidemiology, Nara, Japan.
The HEIJO-KYO study involved data from 1,103 people. Participants had an average age of 72, and all individuals participating in the study stayed home during the daytime. The research team noted that participants underwent annual measurements of their abdominal, or waist, circumference from 2010 to 2014.
Saeki and his team also measured the indoor temperatures of where participants lived. The measurement took place every year for one 48-hour period during the winter seasons. The researchers noted that the average outside temperature on measurement days was 48 degrees Fahrenheit, or 8.7 degrees Celsius. Participants were then divided into four groups based on the average indoor temperatures of their homes.
The study revealed that participants in the lowest indoor temperature group were at 50 degrees Fahrenheit, or 10 degrees Celsius, had an average waist circumference of 32 inches, which the researchers said was 1.4 inches smaller than participants grouped in the highest indoor temperature group. The team found that participants in the highest indoor temperature group were 33.4 inches on average.
The researchers said that the findings held true even after accounting for participants' age, sex, physical activity, total calorie intake and socioeconomic status.
The study was presented recently at the Endocrine Society annual meeting in Boston.