Published: Thu, June 13, 2019
Medical | By

Sleeping with the TV on makes women gain weight

Sleeping with the TV on makes women gain weight

Researchers from the U.S. National Institute of Environmental Health Sciences (NIEHS) examined 43,722 women aged 35 to 74 years.

People face an increased risk of obesity if they fall asleep with the television on, according to new research. "It seems reasonable to advise people not to sleep with lights on", Park and Sandler said.

In analyzing the health and lifestyle data on almost 44,000 US women enrolled in an ongoing breast cancer study, scientists discovered that those who reported sleeping at night in a room with a television on or a light were more likely to gain at least 11 pounds over about five years than those who slept in darkness.

Keeping a light on might also result in poorer sleep. The research was anything but a controlled test thus it can't demonstrate whether or how the exposure to fake light during the evening may straightforwardly cause weight gain.

"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", the researchers conclude.

Published Monday in the JAMA Internal Medicine, the National Institutes of Health report isn't concrete proof but builds on other evidence that artificial light messes with our metabolism.


More research is needed to better understand the link and determine whether reducing light at night may prevent obesity, the authors concluded. The association with having light coming from outside the room was more modest.

They found that using a small nightlight was not associated with weight gain, but women who slept with a light or television on were 17 percent more likely to have gained five kg or more over the follow-up period.

Among women who weren't obese at the study's, those who reported exposure to any light at night were about 20% more likely to become obese during the study, compared with those who didn't report exposure to light at night. "Further prospective and interventional studies could help elucidate this association and clarify whether lowering exposure to ALAN while sleeping can promote obesity prevention".

The findings held even after the researchers took into account factors such as where participants lived (in an urban, suburban or rural area), their household income, their level of caffeine and alcohol consumption, and any experiences of depression or high stress.

Dr. Phyllis Zee, an expert in sleep and circadian rhythm disorders at Chicago's Northwestern University, said the study is important because it highlights a behavior that can be easily changed to reduce the risk of gaining weight.

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