To sleep, perchance to dream, in an increasingly bright world

The bright lights of big cities may be contributing to our national sleep deficit, says new research released Tuesday.

Over eight years, Stanford neurologist Dr. Maurice Ohayon and his team interviewed 15,863 people from cities large and small about their sleep patterns. Then they used data from the Defense Department’s Meteorological Satellite Program to plot the level of nighttime light the interviewees were routinely exposed to.

Compared with people living where crickets chirped and stars could be seen in the night sky, those living and sleeping in more intensely lighted locales were 6% more likely to get fewer than six hours of sleep per night.

They were more likely to complain of daytime drowsiness and to complain of poor sleep quality (29% vs. 16%). And they were more likely to wake up in the middle of night confused (19% vs. 13%).

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People who slept in areas with high light exposure got, on average, 10 fewer minutes of sleep per night compared to those who slept in low-light locales — 402 minutes compared with 412.

Those living in urban areas with 500,000 people or more were exposed to nighttime lights that were three to six times more intense than were those living in small towns or rural areas.

Ohayon, who will present his findings next month to the American Academy of Neurology’s annual meeting in Vancouver, suggested that our 24/7 society might demand nighttime lighting. But if further research confirms that it’s cutting into the quality and quantity of sleep we get, we may need blackout shades and sleep blinders to ensure we get our shut-eye.

The new research comes against the backdrop of growing concern over the impact of shift work and pervasive electronic and digital devices on Americans’ sleep patterns. Both erratic work hours and late-night electronics use are linked to less sleep and poorer sleep in American workers.

Inadequate slumber is, in turn, linked to obesity, metabolic disturbance and poorer overall health. Researchers are keen to illuminate the complex relationship between sleep, light and health, and to glean whether more darkness might bring better health.

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