“According to a new study, women who slept with the television or light on gained 11 pounds or more compared to those who slept in the dark,” reported NBC Nightly News in June. “Using smart devices as you nod off could increase your risk of obesity by 33 percent.”
Before you get so worried that you can’t sleep, relax.
The study tracked roughly 43,700 women for nearly six years. Those who slept with the light or TV on were 17 percent more likely to gain at least 11 pounds than those who slept in the dark. (It’s not true that they “gained 11 pounds or more compared to those who slept in the dark.”)
And women who slept with the light or TV on were 33 percent more likely to develop obesity over the six years. (The study didn’t ask about “smart devices.”)
Those errors aside, does something else about women who sleep with a light or TV on explain why they are more likely to gain weight?
At the outset, those women were heavier and they were more likely to get less sleep, to take longer to fall asleep, to take naps, and to have an irregular sleeping routine.
So did the TV or light cause those problems? Or do poor sleepers watch TV to fall asleep? This study couldn’t say.
To their credit, the researchers took into account factors like age, race, education, income, smoking, alcohol, caffeine, depression, and “perceived stress.”
But even they acknowledged that they could have missed something.
Sleeping with the light or TV on “might reflect a constellation of measures of socioeconomic disadvantage and unhealthy lifestyle behaviors, all of which could contribute to weight gain and obesity,” they wrote.
“We were unable to disentangle the temporal relationship between exposure to [artificial light at night] and other factors, including unhealthy diet, sedentary lifestyle, stress, and other sleep characteristics.”
Bottom Line: Have trouble sleeping? It wouldn’t hurt to try turning off the TV or smart devices.
The information in this article first appeared in the October 2019 issue of Nutrition Action Healthletter.
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