City Streetlights May Cut Into Sleep Quantity and Quality

Barking dogs, crying babies and snoring spouses are almost guaranteed to ruin a night’s sleep. But did you know the streetlights outside your window also can leave you sleep deprived?

An April 2016 study that explores the link between outdoor nighttime light and the sleep habits of Americans found that people who live in well-lit urban areas may not be sleeping as well as those in unlit rural areas, leading them to feel fatigued and even suffer from bouts of late-night disorientation or confusion.

The research was presented at the American Academy of Neurology’s annual meeting in Vancouver, Canada.  

“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,” said psychiatrist Maurice Ohayon, the study’s coauthor and a professor of psychiatry and behavioral sciences at Stanford University School of Medicine.

“We use streetlights to be more active at night and increase our safety and security. They help us see more clearly when we drive,” he said. “The concern is that we have reduced our exposure to darkness, and it could be affecting our sleep.”

The study involved nearly 16,000 people who were interviewed over an eight-year period about their sleep habits and quality of sleep. People living in urban areas were 6 percent more likely to sleep less than six hours per night than people in less intense light areas. In addition, they were more likely to be dissatisfied with their sleep quantity or quality, report fatigue and wake up confused.

Ohayon, who heads up Stanford’s Sleep Epidemiology Research Center, recommends using blackout shades or sleep masks in the bedroom and limiting light-emitting diode (LED) light exposure from cellphones and computers near bedtime.

The blue color cast by new LED streetlights hasn’t helped, he said, adding that LED streetlights could be developed in different colors. He hopes his research will help convince cities to change the color. “Blue is the worst.”