Teenagers who spend 3 hours a day or more in front of the television are at risk of developing sleep problems later in life, new research reports.

Investigators found that, among 14-year-olds who had little trouble getting a good night’s rest, those who watched at least 3 hours of television each day were more than twice as likely to have trouble with falling asleep and frequent nighttime waking at ages 16 or 22.

Moreover, teens who cut back on their TV time from at least 1 hour per day at age 14 to less than 1 hour per day at age 16 were less likely than teens who did not change their viewing habits to suffer sleep consequences later in life, the authors report in the Archives of Pediatrics and Adolescent Medicine.

“In the same way that teens should avoid cigarette smoking because it is associated with risk for a variety of health problems, heavy TV viewing - i.e., more than 1 to 2 hours per day - should also be avoided,” study author Dr. Jeffrey G. Johnson told Reuters Health.

Currently, the American Academy of Pediatrics recommends that young people watch no more than 2 hours of television every day.

Numerous studies have linked TV viewing to sleep problems, but few have tried to establish whether people who have trouble falling asleep watch more TV to pass the time, or whether watching TV itself causes the sleep problems.

To investigate, Johnson and his colleagues interviewed 759 mothers and their teen children when they reached an average of 14, 16 and 22 years of age.

Watching many hours of TV each day was linked to later sleeping problems, and young teens who clocked in at least 3 hours each day were more than twice as likely to report having at least two sleeping problems by early adulthood.

Moreover, 14-year-olds who had sleeping problems during their adolescent years appeared to be no more likely to watch many hours of television in early adulthood, suggesting that watching television likely leads to sleeping problems, and not vice versa.

Johnson, who is based at Columbia University in New York, explained that not all television programs may be equally damaging to sleep, and those that contain disturbing or upsetting content are likely more disruptive than others.

Although the reasons why television may disturb sleep remain unclear, Johnson said studies suggest that watching late night television may put people in a state of “heightened alertness and physiological arousal,” preventing them from falling asleep with ease.

In addition, he noted that being exposed to many hours of the bright light of the television screen may throw people off their sleep-wake cycle, while too little physical activity may cause people to become restless and struggle with sleep.

In an accompanying editorial, Dr. Mary A. Carskadon of Brown Medical School in Rhode Island noted that many young people in the United States are not getting the 8.5 to 9.5 hours of nightly sleep they require, putting them at risk of problems with metabolism, immune system problems, fatigue and depression.

Teens who think they can “get by” on less sleep “are often not really getting by at all,” she writes.

SOURCE: Archives of Pediatrics and Adolescent Medicine, June 2004.