How sleeping in the pitch black could help you lose weight

Sleeping in a completely dark room helps the metabolism to work properly, scientists believe, as they warn that using iPads at night could harm the body-clock

By Sarah Knapton, Science Correspondent

IPads, televisions and computers in bedrooms may be fueling the obesity epidemic because rooms are not dark enough for the metabolism to work properly, scientists claim.

A new study suggests that sleepers need pitch black conditions for the body to produce a healthy level of hormones and regulate the conversion food and drink into energy.

But ambient light from screens, or the street light which creeps under curtains or blinds, can harm the production of melatonin and stop the body processing food as efficiently.

Scientists at the University of Granada discovered that injections of melatonin helped combat obesity and diabetes in rats by regulating their systems.

They believe recreating similar levels of the hormone though sleeping in the dark would have a similar impact in humans.

“Melatonin is a natural substance present in plants, animals and humans," said Prof Ahmad Agil. "It works as a hormonal signal released during the night to establish circadian rhythms.

“Currently this process is frequently interrupted as a result of excessive exposure to artificial lightning during the night. For instance, many people are in the habit of sleeping with their lamps, TVs or their computers switched on, or with the blinds drawn up.

“For all these reasons, it is important to try to sleep in absolute darkness, to avoid interference in the generation of melatonin.”

One in four adults in England is obese and these figures are set to climb to 60 per cent of men, 50 per cent of women, by 2050.

Three in every 10 children aged between two and 15 are currently overweight or obese.

Obesity and diabetes already costs the UK over £5 billion every year which is likely to rise to £50 billion in the next 36 years.

Prof Agil believes that the obesity epidemic is being driven jointly by sedentary lifestyles, increasing consumption of high calorie foods and excessive exposure to artificial lighting which is reducing melatonin levels.

He thinks that keeping the lights on for a long time after it gets dark could be disrupting the body's natural circadian rhythm and harming metabolism.

The researchers suggest reducing evening lighting, and the use of computers, during the hours of darkness.

Computers, televisions and iPads are particularly disruptive because the emit blue light, which is the same wavelength as morning light. A warmer, more yellow light is better during the evening, say experts.

The study was published in the Journal of Pineal Research.

Source: http://www.telegraph.co.uk/health/healthnews/11139548/How-sleeping-in-the-pitch-black-could-help-you-lose-weight.html