Sleep is essential for many bodily functions, every bit as important as hydration and nutrition. In fact, if you go long enough without sleep — somewhere between and seven and 10 days — you will die. This probably has something to do with thermoregulation, but nobody wants to volunteer for the studies to find out.
Perhaps the group most impacted by sleep deprivation is teenagers. It is natural for them to have a shift towards "eveningness" as their circadian rhythms move to a later physiologic bedtime. That may work to their advantage, considering they have more and more to do after school in our present go-go culture. After school is over, and school team practice is over, and select team practice is over, and youth group is over, they have just enough time to eat dinner and get homework started — they're lucky to get to bed by midnight. That might actually work out, if they were able to get their requisite 8.5 to 9.5 hours of sleep before getting up for school the next day. However, our modern system does not accommodate that schedule.
Whatever its origins — busing demands, limited daylight practice times after school, childcare issues for parents — high school starts too early. On average, teens get two hours less sleep than they need on school nights, resulting in impaired cognitive function, fragmented memory and learning and mood disturbance. That sleep debt cannot be repaid in one weekend, no matter how late they sleep in.
Some states are trying to regulate this by having high schools start no earlier than 8:30 am. There is ample evidence to show that later start times reduce auto accidents, decrease depression and improve school performance. During such an essential part of life, one that requires engaged learning and social interaction, would it not be better for our adolescents to have an attentive six hours, rather than a befuddled seven hours, of class time per day?