Is Artificial Light Messing With Your Sleep?

Whether it’s a neighbor’s barking dog, your snoring spouse or that glass of wine you had with dinner, there are plenty of things that can sabotage a good night’s sleep. A big one is artificial light.

A growing body of research reveals that the conveniences we take for granted, like flipping on a light switch or powering up an electronic device, come at a cost to our sleep. Less time spent outdoors in natural daylight and more time exposed to artificial light at night is likely messing with our circadian rhythms, in part by suppressing the production of melatonin, a hormone that tells the body when it’s time to go to sleep. 

Blue light seems to have the strongest effect on our sleep patterns — and compared with old-school incandescent light bulbs, today’s energy-efficient LED bulbs put out a lot more blue light.

“Things have changed drastically since electricity began lighting our homes a little more than a century ago; we’ve become a 24/7 society, living in environments that are lighted 24 hours a day,” says Dr. Maurice Ohayon, a professor of psychiatry and behavioral sciences at Stanford University School of Medicine. 

In a study Ohayon coauthored, people living in well-lit urban areas averaged fewer hours of sleep per night than people in less intensely lit areas. His research, published in 2016 in the journal Sleep, involved nearly 16,000 adults ages 18 and older who were interviewed over an eight-year period about their sleep habits and quality of sleep.

More recent studies back him up. In a cross-sectional study of 13,474 adults ages 65 and older published in 2022 in Environmental Research, scientists used satellite images to determine how much outside artificial light at night each person was exposed to at their homes. 

Based on participants’ self-reported sleep schedules, the researchers concluded that those exposed to the most artificial light at night were more likely to get six or fewer hours of sleep. They slept about 17 minutes less per night on average than people exposed to the least light.