According to the National Sleep Foundation US teens who have a lot of electronic gear in their bedrooms are twice as likely to fall asleep in school. The study found that 97% of adolescents (grades 6–12) had at least one electronic gadget (computer, mobile, television, music device etc) in their bedrooms.
The survey reported that adolescents with four or more devices in their bedrooms were much more likely than their peers to get an insufficient amount of sleep at night and almost twice as likely to fall asleep in school and while doing homework.
The NSF’s Dr. Carskadon noted:
“Many teens have a technological playground in their bedrooms that offers a variety of ways to stay stimulated and delay sleep. Ramping down from the day’s activities with a warm bath and a good book are much better ways to transition to bedtime. The brain learns when it’s time to sleep from the lessons it receives. Teens need to give the brain better signals about when night-time starts … turning off the lights—computer screens and TV, too—is the very best signal.”
Three devices (if alarm clocks count) and an electric blanket that doesn’t get much use between the two of us in our bedroom. So I can’t use that as the excuse for being tired. (And I'm no teenager.) More likely to be going to bed late and getting up early!