to understand why it’s so incredibly difficult to wake a sleeping teen at 6:00 a.m., think how hard it would be if you had to get up for work at 3:00 a.m.—it’s pretty much equivalent.
For sleep to occur, the clock-dependent alertness that’s generated by Process C needs to be turned off by melatonin. For children and adults who go to bed at 10:00 p.m., melatonin secretion, or dim light melatonin onset, typically begins about six hours earlier, around 4:00 p.m. But in adolescents melatonin onset may not occur until hours later.
Still another problem is the length of the day. Children’s and adults’ body clocks follow a day that is approximately 24.3 hours long, but— you guessed it—the adolescent body clock beats to a different drum. Teens’ biological processes work to a slightly longer day, one that can