Our addiction to constant live updates on Facebook, the latest iPhone app and the ever-constant flickering of the TV is taking its toll on Americans' sleep, according to local sleep specialists and a new poll on sleep habits.

"It's a pretty significant problem," said Dr. Andrew Vernon of the Chattanooga Sleep Center. "Our bodies are based on a circadian rhythm. Light, we wake up; dark, we go to bed. If you're exposed to bright light in the evening time, it postpones the onset of sleep."

Nearly everyone in the National Sleep Foundation's Sleep in America survey - 95 percent - said they use electronics such as televisions, computers or cell phones in the hour before bed at least a few nights a week.

But teenagers are most likely to indulge in late-night technology use, the survey found, resulting in daytime sleepiness that affects mood, memory and ability to learn.

The annual survey, released this week, polled about 1,500 people and questioned respondents on various aspects of their sleep health and habits.

Teenagers and young adults were about twice as likely as those over 30 to say they played a video game within the hour before bedtime at least a few times a week.

"Teenagers are already the most sleep-deprived segment of the population," said Dr. Vince Viscomi, local sleep medicine specialist.

He said he's treating a few children whose technology use is the source of their sleep problems.

"I have kids who can't get up to go to school anymore," he said.

One mom even had to start home-schooling her child because he couldn't get up in the morning, Viscomi said.

The poll showed cell-phone use is a major generational divide. More than half of 13- to 18-year-olds and nearly half of 19- to 29-year-olds reported that they send, read or receive text messages nearly every night during the hour before bed.

That's compared to 15 percent of adults 30 to 45 and just 5 percent of baby boomers.

About one in 10 of those age 13 to 18 said they are awakened almost every night by a phone call, text message or e-mail, according to the poll.

About 43 percent of those age 13 to 64 reported they rarely or never get a good night's sleep on weeknights, the survey found.

"This is a medical problem. It should not be taken lightly," said Dr. Anuj Chandra, sleep specialist with the Advanced Center for Sleep Disorders in Chattanooga.

Before long, he believes, the problem will even have a name, such as "technology-induced sleep disorder."

Watching a bright computer or video game screen before bed is more disruptive to sleep than light from a regular light bulb, doctors said.

The blue-spectrum light from electronic screens is an "alerting" mechanism, Viscomi said. The light hinders the body's natural production of melatonin, a sleep-inducing chemical whose release is triggered by darkness.

Those who keep an iPhone or computer at their bedside often reach for it when they wake up at night. Then they struggle to go back to sleep, experts say.

"It sort of becomes a self-perpetuating cycle," Viscomi said. "It makes it harder for them to go back to sleep."

If you're having trouble going to sleep or wake up in the night and can't get back to sleep, doctors recommend getting out of bed in 20 minutes or so and doing something calming in low light, such as reading or writing.

For parents, removing all temptation from their child's rooms is key, Viscomi said. Kids' bedrooms should be free of phones, computers and TVs, he said.

"The key is to take it out of their easy-access environment," he said.

Some people can use simple behavior modification techniques to cut down on the late-night tech time, but others find it much harder to unplug and disconnect, Viscomi said.

"Some people understand it, but they really can't change their behavior," he said.

Taking time to wind down is critical to preparing the body for sleep, Chandra said.

"We need to treat the one hour before bedtime as sacrosanct, a time to unwind, meditate, completely cut off any stimulating activity," he said.