Electronic devices' blue glow could cause sleepless nights

Bedtime is no longer just time for a good book, some late-night TV or snuggling. Today, many people don't succumb to sleep until they've checked email on their phones, watched a video on a tablet, viewed Instagram, finished up some work on their laptops -- or all of the above.

Sleep experts say all this exposure to bright screens before bed, or often in bed, can bring on insomnia. Though the full impact of screen time on sleep isn't clear, a National Sleep Foundation survey in 2011 found that 63 percent of people 13 to 64 years old reported not getting enough sleep. Older people said they frequently watched TV before bed, while younger people were more likely to be fiddling with their cellphones.

The study didn't prove a connection between light exposure and lack of sleep, but Long Island sleep doctors say they definitely see a link.

"When we go to bed and check our email, that's one of the worst things we could be doing since it contributes to insomnia," said Dr. Marta Maczaj, co-director of the Sleep Disorders Center at St. Charles Hospital and Rehabilitation Center in Port Jefferson. And it's not just kids who are drawn to their phones, she said: "We see a lot of business executives who are always attached to a smartphone."

Blue spectrum light

The main problem stems from the screens that emit bright light in the blue spectrum, said Dr. Harly Greenberg, medical director of the North Shore-LIJ Sleep Disorder Center in New Hyde Park. "Many electronic devices have been shown to suppress nocturnal release of the sleep hormone melatonin when used for prolonged periods of time, at least an hour, at sufficient intensity," he said.

Lots of devices emit blue light.

"Light-emitting diodes, or LEDs, have been replacing traditional incandescent light bulbs," said Dr. Sofia Rubinstein, an attending physician and associate chairwoman for research at Nassau University Medical Center in East Meadow. "These LEDs are now widely used in most electronic devices, such as televisions and computer screens, laptops, tablets, Kindle and hand-held devices. They are rich in blue light."

As a result, the devices can disrupt sleep more than old-style incandescent lighting. "However, even dim light can interfere with a person's circadian rhythm and melatonin secretion," Rubinstein said. "Artificial light at night is part of the reason so many people don't get enough sleep."

Unplug (or filter the light)

One solution is to simply avoid watching TV and using computers or cellphones in the hours before bed.

"What you should really be doing in bed is relaxing and going to sleep or being intimate with someone," Maczaj said. "Having the television, laptop or smartphone in the bedroom is a no-no."

For many people, though, even a brief detox from electronics isn't feasible. What then?

"If you work a night shift or use a lot of electronic devices at night, consider wearing blue-blocking glasses," Rubenstein said.

Or, suggests Greenberg, if you're using an electronic device like a tablet, "lower the intensity or brightness of the screen to the minimal level and, if possible, shift the color spectrum of the screen from the blue range to the warmer red-orange range to reduce the impact of these devices on sleep." Some newer devices are equipped with that ability, he said.

However, Greenberg cautioned that good sleep depends on more than limiting light exposure before bed. Mentally stimulating activities like reading emails can hurt sleep, too.

"Before sleep, activities should be relaxing and not stimulating," he said.