People face an increased risk of obesity if they fall asleep with the television on, according to new research.
A survey of almost 44,000 people found that women who fall asleep while exposed to artificial light are more likely to gain weight and become obese or overweight in the next five years.
The findings - published in a journal called JAMA Internal Medicine, and collected by researchers from the National Institute of Environmental Health Sciences - suggest that turning off screens and lights while you sleep could be a way of tackling obesity.
Study looked at women in America
Researchers followed 43,722 women aged between 35 and 74 years old in the US over a period of five years.
The women provided information about their exposure to artificial light at night time, as well as their weight and Body Mass Index (BMI).
The results showed that the women who slept with an artificial light or television in the same room were 17 per cent more likely to gain 5kg or more in the five year period.
It also found that women who slept around artificial light were 22 per cent more likely to become newly overweight during the period, and 33 per cent more likely to become newly obese.
The authors said, “These results suggest that exposure to artificial light at night while sleeping may be a risk factor for weight gain and development of overweight or obesity.”
Could also be linked to other factors
The findings are not conclusive however. It is noted in the report that habits such as falling asleep in front of the television were often indicative of a sedentary lifestyle, which itself is linked to weight gain.
However, commenting on the study, Professor Malcolm von Schantz, from the University of Surrey, said, “The findings make perfect biological sense. We know that light in the late evening will delay our body clocks.
“We know from experimental studies in people that light at night affects our metabolism in ways that are consistent with increased risk of metabolic syndrome.
“These new findings won’t change the advice to maintain good sleep hygiene, and avoid light and electronic distractions in the bedroom, but they add further strength to the case for this advice.”