Indoor Temperatures May Worsen Obesity

Observing that domestic winter indoor temperatures in the United States, United Kingdom , and other developed countries seem to be rising, Fiona Johnson, from University College London (United Kingdom), and colleagues suggest that biological effects of time spent in thermal comfort may promote obesity, by turning down the body's own thermostat and its ability to effectively burn fat.  Taking a particular interest in brown fat, the researchers identified its role as a thermogenic organ, dissipating energy in the form of heat: indeed, brown adipose tissue activation -- and the resulting energy expenditure -- is much more likely to occur in cold environments. The team observed that decreasing the ambient temperature from 22°C (71.6°F) to 16°C (60.8°F) led to the detection of brown adipose tissue in almost all healthy study subjects. As well, under conditions of full activation of the brown adipose tissue, the team calculated that there would be an increased energy expenditure leading to a 4 kg (8.82 lb) weight loss over a year. Writing that: “Recent studies of the role of brown adipose tissue  in human thermogenesis suggest that increased time spent in conditions of thermal comfort can lead to a loss of [brown adipose tissue ] and reduced thermogenic capacity,” the researchers identify: “[A need] to establish effects of changes in thermal exposures on weight, which may raise possibilities for novel public health strategies to address obesity.”