This isn't new material for me, but something to think about anyway:
As adolescents grow, their sleep cycles change (Carskadon, 1999). During adolescence teens tend to stay up later and sleep later. Some of these changes are explained behaviorally...But some of the changes are due to intrinsic, biological changes. Even more seriously, researchers, doctors, and teachers are realizing that circadian rhythms and school schedules are out of synch (Carskadon, 1999). The result is excessive sleepiness, inferior academic performance, and even accidents.
Pioneering research has begun to focus on circadian rhythms and circadian rhythm disorders ...Measurable by biological events, like melatonin, circadian rhythms control the timing of rapid eye movement sleep (REM). Research is beginning to show that circadian rhythms are developmental and change with growth from childhood, to adolescence and adulthood.
One of the most fundamental benefits of homeschooling is that it leaves families freer to choose their own schedules. That includes sleep schedules. Most days of the week, I could, if I chose, arrange things so that the children and I could sleep very late or take naps in the middle of the day -- at least in theory. We have no buses to catch, after all.
Kids generally don't get enough sleep when they have to keep to a school schedule that starts early in the morning and leaves no room for a nap:
Early survey research at Stanford University, showed that as pubescent girls matured they preferred evening to morning schedules... In other words, as the girls' bodies changed so did their sleep cycles. This is more than staying up late to have fun. Changing sleep cycles are biologically based. Furthermore, parent surveys and teen sleep diaries indicate that during the school year, teens average about 2 hours/per night less sleep than in the summer. The effect is cumulative. So losing 2 hours sleep each night adds up to a total of 10 hours lost sleep by the end of the week.
As adolescents' bodies change, they stay up later but still show afternoon dips in alertness. Previously believed to be a sleep pattern of younger children, who once took naps in school, this "siesta" effect is pronounced even into later adolescence. Changing circadian rhythms of adolescent bodies and early school schedules are out of sync.
Looking back at my own late adolescence, especially my first experiences with setting my own schedule in college (my freshman year, of course, but before that I attended a summer credit-earning residential program for high school students) -- I vividly remember how quickly I (and many of the others my age) re-adopted the afternoon nap that hadn't been possible since kindergarten. Often, after returning from classes, I'd pass out on my bunk and not get up till the dining hall was about to open.
Looking specifically at my preadolescent son -- he is 11 -- I could let him sleep as long as he wished almost every morning, and let him set his own schedule for schoolwork most of the time. He's proven himself responsible and capable of plowing through his daily to-do list with little supervision, and it is obvious that he has developed the ability both to self-teach and to know when it's time to ask for help learning something.
Typically, though, I haven't given him total sleep/work freedom. There are a few pressures that work against the "everybody can sleep as much as they need to" model, at least in our family. The challenge is in finding the balance.
(1) The rest of us may not have to be out the door early in the morning, but Dad does. If a teen sleeps in late, he misses time with his father (or whichever parent is the breadwinner) that he could otherwise be having. Of course, he could get more by staying up late -- but many families prioritize early bedtimes because it gives Mom and Dad a block of time without interruptions.
(2) I like there to be a time in my day when I'm "done" with school. I get a feeling of satisfaction when everybody has cleared out of the schoolroom early enough that I can straighten it up and leave it in the late afternoon.
I realize that a mother's schedule is not meant to conform to outside-world expectations. But deep down I like the illusion of having something less like a vocation to which I give myself fully in my my every moment, and more like a JOB, because JOBS eventually have a quitting time, after which I can crack open a beer and put my feet up and chat with my husband about his day.
(3) A fairly predictable school schedule is the tool that helps me give time and attention to each child over the course of the day. This is a big deal. I have to have enough time in the morning, and enough time in the afternoon, especially to work one-on-one with my five-year-old and my eight-year-old. (Thank God my five-year-old learned to read precociously early, because that is one less time-intensive activity I need to work on with her.) We have a rule around here: "You may not interrupt me if I am teaching someone younger than you." If my oldest were completely free to set his own schedule, it would be trickier for him to work with mine.
Still, the daily schedule may not be optimized; perhaps I should re-evaluate it with tween-sleep as a high priority.
(4) I try to do a couple of school subjects, as well as lunch, together as a family. This means calling my older kid away from his own work -- or his bed -- and bringing him "in touch" with the rest of the children.
(5) We aren't totally isolated from the outside world and its schedules. There's Sunday morning Mass, for one thing -- and if we sleep in and go to late Mass, there's just so much less of the day left to play. Two days a week we co-school with another family, and that means getting up early (at least when it's our turn to drive and car-pool) so we can start early enough to get the work done and get home to Dad. When doctor's appointments and such need to happen, first thing in the morning seems best because it interrupts our day the least.
(6) There is pressure to teach conformity with the outside world. Someday he's going to have a job, and it might make him get up in the morning and keep a traditional workday schedule, right?
In theory, I reject the "but he'll have to learn it eventually, so we have to work on it now" philosophy. Most lessons can wait for developmental readiness most of the time, and there is much more natural motivation to learn when the natural need arises. Still, all homeschoolers (I think) have to make decisions like this all the time. Even though as homeschoolers, our children don't have to jump through the same hoops as all those "normal" people, when they are adults they will be expected to act like "normal" people some of the time, and we want to prepare them to be able to conform by choice when it's in their best interest.
Sooner or later most people will need the skill to arrange sleep schedules in order to meet somebody else's demands. The question is, do they need practice with this more than they need... well... sleep?
It's yet another are where we must decide how best to strike the balance among the natural needs of each individual living in the family, all with one eye to the sometimes unreasonable but often unavoidable demands of the outside world. This is never a simple question, and parents encounter it and answer it -- not always easily, and not always willingly -- again... and again... and again.