How light or dark your bedroom is doesn’t just affect the quality of your sleep. It could influence several health problems, according to a new study published in the journal Sleep. Researchers at Northwestern’s Center for Circadian and Sleep Medicine in Chicago studied over 550 participants between the ages of 63 and 84. The participants wore devices that measured the amount of light in their bedrooms for more than a week. They found that older adults who used night lights, or left their TVs, smartphones or tablets on in the room were more likely to be obese, and have high blood pressure and diabetes, compared with adults who were not exposed to any light during the night. To improve your sleep – and your health – keep your bedroom as dark as possible. If you need a nightlight, try to use a red or amber light, and keep it close to the floor, away from your bed. If you can’t control outside light that gets in the room, try blackout curtains or wearing an eye mask.