Around 2/3 of all Americans don't get enough sleep, and using technological gadgets with bright screens is a major part of the problem. In fact, almost all of the respondents to the Sleep in America poll said that were "very active" in their use of technology in the few hours before bed time.
The sleepiest group of all, teens from 13 to 18, reported that most nights they texted an hour before bed, and that they got nearly two hours less sleep than the amount recommended by experts. This low amount of sleep affects their performance in school and extracurricular activities. One 17-year-old respondent to the survey even reported falling down stairs and scraping his arm from being so drowsy.
The reason technological gadget like cell phones, televisions, hand-held games and computers are so disruptive to your sleep cycle is that their brightness suppresses the release of melatonin in your brain.
Melatonin induces sleep but the brightness of the screens tells your brain that it is still daylight and not time to sleep yet. Because of this, a person's sleep cycle shifts to later and later, but the cycle becomes vicious when people start watching late-night television or surfing internet pages because they can't sleep.