A new study found that people exposed to artificial light while sleeping made them 17 percent more likely to gain weight
If you typically fall asleep to the sounds of a late-night host interviewing celebrities, you may want to consider a different method — a new study found that sleeping with the TV on may make you gain weight.
The researchers looked at data from 43,733 women between the ages of 35 and 74 from July 2003 to March 2009. They asked them about the light sources in the room where they sleep and sorted their responses into four categories: no light, small nightlight in the room, light outside the room (such as street lamps or car headlights) or light or a television in the room. They also recorded each participant’s height and weight over the course of the study.
The results were bad news for nighttime TV lovers — they were 17 percent more likely to have gained 5 kg., 13 percent more likely to have gone up in BMI by 10 percent or more, 22 percent more likely to have become overweight, and 33 percent more likely to have developed obesity.
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While light in the room doesn’t directly cause weight gain, the extra exposure leads to restless sleep and limits deep sleep time. That lost sleep affects appetite hormones and can lead to overeating, a slowed metabolism and lower physical activity.
“It seems reasonable to advise people not to sleep with lights on,” lead author Dr. Yong-Moon Park, a postdoctoral fellow at the National Institute of Environmental Health Sciences, and senior author Dale Sandler, chief of the NIEHS’s Epidemiology Branch, said.
The study confirmed previous findings and thinking on the likelihood of weight gain from sleeping with the TV on, though the study authors say that more research is needed. They also pointed to the light from smartphones, computers, tablets and e-readers as likely culprits.
“Evolutionarily we are supposed to be sleeping at night, in a dark place,” Sandler told USA Today. “It’s much more important than people realize for a whole variety of health reasons.”