On nights when teenagers used their phones after 10 p.m. more than they usually did, they fell asleep about 65 minutes later and slept about 20 minutes less, according to a new study in JAMA Pediatrics published on Oct. 19. The study tracked 425 U.S. teens and also found that phone use in the final minutes before sleep was linked with more time awake soon after falling asleep.
For parents, the findings put numbers on a familiar bedtime argument. A late start to sleep on a school night leaves less time before an early alarm, and too little sleep in adolescence is linked with problems in mood, attention and school performance.
