Night Light

It’s common to fall asleep bathed in the glow of phones, laptops, or other devices. But a new study suggests that sleeping with even a small amount of light may be harmful to your health. 

An investigation tracked 20 people overnight. Half of the group slept in dim lighting and half in darkness. Researchers found that those who slept in dim light had faster nighttime heart rates, and their bodies had more trouble processing sugar the next morning. These changes to the body’s metabolism—the chemical processes needed to sustain life—could lead to long-term health problems, like the disease diabetes.

“Try your best to reduce light at night while you’re sleeping,” says Ivy Mason, a neuroscientist at Harvard Medical School in Massachusetts who worked on the study. Start by turning off all electronics before you hit the hay.