Although doctors and the American Academy of Pediatrics call for later start times that take into account adolescents' sleep rhythms, Emma Davis of the Australian Broadcasting Corporation points out several logistical problems, including the difficulty of coordinating with parents' schedules and the lack of time allotted for extracurricular activities and homework. Later start times might be healthier, but they still present difficulties that need to be overcome.
The AAP's research indicates that adolescents who suffer from regular sleep deprivation are more likely to be overweight, suffer depression, perform poorly in school and get into car accidents. The chronic sleep deprivation is now understood to be inherent to the school system. As adolescents enter puberty, their sleep cycles shift up to two hours later. Polls report that over 80 percent of high school-aged teenagers do not receive enough sleep.
However, shifting school start times to a later hour presents difficulties for parents who may no longer be able to drop their children off before work. During the winter, when the sun sets earlier, children and teenagers may be unable to walk home safely in the dark and have to coordinate rides with each other or adults. Sports practice, which can last anywhere between one to two hours after classes, may become unfeasible.