Go dark! Protect your health by turning off the lights at night.
“Lights out” isn’t just a bedtime decree for children. It might also help adults maintain good health. According to new research, regularly sleeping with a light or the TV on may increase the risk of weight gain and obesity. Researchers looked at data from more than 43,000 women who were asked whether they slept in total darkness or were exposed to artificial light, such as a nightlight, a light outside the room, or a light or television on in the room. The more artificial light the women were exposed to at night, the more prone they were to gain weight over the course of five years. You might wonder how sleeping poorly fits in to the study, since insufficient sleep is also linked to weight gain, but the study showed that artificial light exposure was a separate factor. Be sure to turn off lights, TV, and all computers, tablets, and smartphones before you go to bed. Light-blocking shades can remedy light from street lamps and any other lights that shine in from the outdoors. A simple, inexpensive eye mask can also do the trick—keep one at your bedside and take one with you when you’re away from home!

Source: Association of Exposure to Artificial Light at Night While Sleeping With Risk of Obesity in Women