Older men and women who used nightlights or left their TV, smartphone, or tablet on in the room were more likely to develop obesity, high blood pressure, and diabetes compared to adults who were not exposed to light at night. This is according to a new study published in the scientific journal Sleep.
“Even a small amount of light at night can be harmful. Over time, light can cause metabolic and heart disease,” said study author Dr. Minji Kim, an assistant professor of neuroscience at Northwestern University’s Center for Circadian and Sleep Medicine. Feinberg in Chicago.
The researchers studied more than 550 participants in the Chicago Healthy Aging Study: people aged 63 to 84 wore devices that measured the amount of light in their bedrooms over the course of a week. It turned out that less than half of the participants slept for five hours in total darkness. The rest were exposed to light even during the darkest five hours of the day – usually in the middle of a night’s sleep. The scientists said they don’t know if obesity, diabetes and high blood pressure encourage people to sleep in the light, or if the light leads to these diseases.
Emerson Wickwire, professor and head of sleep medicine at the University of Maryland School of Medicine, said the results of this work add to a growing body of scientific evidence showing the importance of the body’s circadian clock and sleep for overall health, especially among older adults.
“These data show that night-time light exposure increases the risk of two of the most common and costly chronic diseases in the US and worldwide—obesity and diabetes—as well as hypertension, a major risk factor for cardiovascular disease,” Wickwire said.
Scientists have given tips on how to minimize lighting in the bedroom:
– Don’t turn on the light. If you need to turn on the lights for safety, place a dim nightlight near the floor.
– The color of the light is important. Amber or red/orange light stimulates the brain less. Do not use white or blue light and keep it away from the bed.
– If you can’t control outdoor lighting, use blackout curtains or wear a sleep mask.
– Position the bed so that the morning sunlight does not hit your face.