Your natural sleep/wake cycle is biologically determined and known to shift later into the night in adolescence. Sending a teenager to bed earlier does not mea

Your natural sleep/wake cycle is biologically determined and known to shift later into the night in adolescence. Sending a teenager to bed earlier does not mean they will sleep well, or at all, in the period between "bedtime" and their natural sleep phase. The temporal location of sleep, not just its duration, matters. >http://www.wsj.com/articles/teens-need-later-start-to-school-day-doctors-group-says-1408939263 http://www.wsj.com/articles/teens-need-later-start-to-school...