Turn down heat to reduce obesity risk, scientists propose

Keeping homes a little chillier as temperatures drop outside might help people burn more calories and protect their health, Dutch researchers say.

We spend about 90 per cent of our time indoors  at home, school or work, scientists say. Now a paper published in Wednesday’s issue of the journal Trends in Endocrinology & Metabolism proposes a little cold keeps that doctor away since regular exposure to mild cold could increase energy expenditure to tackle obesity.

"What would it mean if we let our bodies work again to control body temperature? We hypothesize that the thermal environment affects human health," Wouter van Marken Lichtenbelt of Maastricht University Medical Center in The Netherlands said in a release.

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The researchers describe two ways that people respond to cold. First, shivering helps protect us from hypothermia. In the past few years, scientists have also shown that adults carry brown adipose tissue, also called brown fat, which burns calories instead of storing them like conventional fat does. Brown fat is found around internal organs and between the shoulder blades.

"Maximal thermal comfort in the built environment may increase our susceptibility to obesity and related disorders, and in parallel requires high energy use in buildings," Lichtenbelt and his co-authors concluded.

"Letting our body spend more energy to maintain thermal balance may positively affect health on a population scale."

The researchers pointed to a Japanese study that found a decrease in body fat after people spent two hours per day at 17 C for six weeks. At their lab, the Dutch team has found that after spending six hours a day at 15 C, people shiver less, felt more comfortable and brown fat is activated.

In both young adults and the elderly, a previous study suggested that gradual temperature variations are accepted without significant discomfort. But Lichtenbelt notes that hospitals and long-term care homes often set the thermostat relatively high during winter.

While research aims to pinpoint the physiological basis, the idea of letting our body spend more energy to maintain its temperature remains a hypothesis that needs to be tested in long-term experiments. Lichtenbelt’s team and others are planning to have people live in cooler environments while tracking their weight.

It's too soon to tell if turning down the thermostat definitely helps with weight loss, Mitchell Lazar, chief of the division of endocrinology, diabetes and metabolism at the University of Pennsylvania said commenting on the paper to HealthDay News.

Previously, researchers in Stockholm have pointed out it’s not yet clear if brown adipose tissue burns more through metabolic activity.