When Melissa McCarthy, star of the movies “Bridesmaids,” “Can You Ever Forgive Me?” and the upcoming “Superintelligence” decided to do something about her weight (she shed 75 pounds), one of her first steps was to change her sleep habits.
“You bring it real down . . . and you go to bed at 7:30 — that's the trick,” she said.
But it turns out there's more to it than that. A new observational study published in JAMA looked at 44,000 women who had no history of cardiovascular disease or cancer, didn't work off-hour shifts, and were not pregnant at the study's start.
What the researchers discovered was that women who reported sleeping in a room with a TV or other lights on were heavier than women who did not.
Furthermore, over the course of about six years, women who slept in even dimly lit rooms gained around 11 pounds more than women who slept in the dark.
The reason light at night leads to weight gain is that it messes with the ebb and flow of light-sensitive hormones such as melatonin and cortisol. That affects your metabolism in many ways.
To avoid weight gain, upgrade your nutrition, increase physical activity, and get that bedroom nice and dark:
• No TV or digital light sources.
• No light from other rooms or fixtures in the bedroom. (Red wavelength light is okay, however. It doesn't affect melatonin levels.)
• Use a padded eye shade.
• Install window shades and curtains to keep light out of the bedroom.