Open your bedroom window at night to prevent obesity and type 2 diabetes, says Oxford prof 

Staying cool could be the key to losing weight and preventing diabetes
Staying cool could be the key to losing weight and preventing diabetes  Credit: Alamy 

Opening your bedroom window at night to allow in a cool breeze could be simple, if chilly, way of preventing obesity and Type 2 diabetes, an Oxford University academic has suggested.

Professor of Endocrinology Ashley Grossman said there was mounting evidence that cooling the body even by just a couple of degrees was beneficial for health.

His comments were made after a new study by Dutch scientists appeared to find a link between global warming and diabetes.

The researchers suggested that a one degree centigrade rise in environmental temperature could lead to 100,000 new cases of diabetes in the US each year because the body needed to burn less brown fat to keep warm, leading to insulin sensitivity and weight gain.

Professor Ashley Grossman Credit: University of Oxford 

Prof Grossman said the research supported the ‘keep cool’ theory of decreasing diabetes and obesity.

“There is some rather encouraging evidence that cooling the body, even by a few degrees, may improve or reduce diabetes,” he said.

“Living in a cool environment may be useful to increase insulin sensitivity and ward off diabetes.

“Together with work indicating that adequate sleep can also help avoid obesity and diabetes, maybe we should all aim have a good night’s sleep in a cool bedroom with the windows open to the night breeze.”

A recent study by Maastricht University Medical Centre in the Netherlands advised turning the thermostat down to between 15 C and 17 C for a few hours a day to keep weight down.

Keeping the temperature down at home and work could be an simple way to avoid weight gain, experts think Credit: Alamy

The experts claimed that because we spend so much time indoors, often in overheated homes and offices, our bodies do not naturally burn calories to keep warm. Temperatures closer to what it is like outside might be more beneficial to health.

Simply being colder raises the metabolic rate - the speed at which calories are burnt - by 30 per cent, and shivering can burn around 400 calories an hour as it increases the metabolic rate fivefold.

The new research Leiden University Medical Center, which was published in BMJ Open Diabetes Research & Care,  set out to investigate if global increases in temperature were contributing to the type 2 diabetes epidemic.

Nearly two thirds of Britons are overweight or obese and some 3.6 million people have diabetes, most of which is Type 2.

They looked at temperature data and diabetes incidence in 50 US states as well as the territories of Guam, Puerto Rico and the Virgin Islands.  They found that on average, per one degree centigrade increase in temperature, type 2 diabetes incidence increased by 0.314 per 1,000.

Sleeping with the window open could help people burn more fat Credit: Kevin C Moore

The human body stores two types of fat, white and brown. While white fat stores calories, brown fat is converted into energy and heat so keeping cool is thought to stimulate brown fat, and bring weight loss.

However although the link between a cold body and diabetes is fairly well established, researchers said the idea that it might be linked to climate change was unlikely.

Dr Louise Brown, Senior Statistician at the Medical Research Council Clinical Trials Unit at University College London, said: “Overall, the uncovering of this association is interesting but I do not feel that is of great help in our fight against the increasing global incidence of diabetes, unless they are suggesting that we all move to colder climates.

“If they have stumbled across a useful pointer that leads to appropriate metabolic research on the role of brown fat in the development of diabetes then great, but their claims are too strong at this stage.”

Prof Sir David Spiegelhalter, Winton Professor for the Public Understanding of Risk at the University of Cambridge, added: “Even if these estimates were true, it would mean a 2 degrees rise in average temperature was associated with an increased incidence of diabetes of 0.7 per cent.

“In those circumstances I don't think this would be the biggest concern."