11/06/2007 03:56 pm ET | Updated Nov 17, 2011

What If Your Kid's First Bell Rang Close to Lunchtime?

If I could go back in time and be a high school student again (let me re-phrase that: if I had to go back and do it all over again), I'd like to attend one of the schools in Toronto where kids can start classes as late as 11:30 a.m.

Finally, we are seeing changes happen in school systems to support students' natural rhythms that prefer later nights and even later mornings. It hasn't happened yet, but I read an article online reporting that next year one high school in this Canadian city will be chosen for allowing its students to sleep in--big time. In the United States, school districts in 19 states have implemented later start times, but I don't think any push it out to as late as 11:30! For adults, that sounds like lunchtime.

When people (especially parents) ask me about their kids' sleep

habits, I explain to them that everyone's circadian pacemaker ticks at

a different rate, but as you age your pacemaker will speed up or slow

down, thus altering how your body responds to the 24-hour cycle. Babies

don't get a rhythm going until about 6 months of age, at which point

they establish a rhythm that matches closely with the 24-hour day.

Teenagers typically don't go to bed much before 11 at night. From the

age of about 15 to 25, that pacemaker slows down so a 17-year-old's

body usually won't want to go to sleep early or get up early. The

chemical responsible for sleepiness is secreted later at night and

turns off later in the morning, leading to a "sleep phase delay." (So

your teen's weird sleep routine isn't all that weird, and it's not

necessarily a means of rebellion.)

Sometime during our late 20s the body clock speeds back up again so

it matches the 24-hour day. Then, later on in life our clocks speed up

further so the body doesn't match so well with the 24-hour day. It

wants to go to bed early and get up super early, which is what you find

Granny and Gramps doing. At an older age the body also doesn't

experience as strong of a fluctuation in core body temperature

throughout the day, which affects the rhythm. This might explain

partially why older people's rhythms aren't as robust and clearly

defined as younger people's. Older people will weave in and out of

being semi-sleepy and semi-awake throughout the day and night.

The reasoning behind the suggested new start time for schools is

more than just helping teens match their unique sleep schedule. Kids

(and for that matter, adults) who get a good night's sleep perform

better, are more capable and prepared to learn new skills, and can

manage their emotions better (a dream for any parent with a teen).

What's more, research on adolescents' brains indicates that kids' brain

patterns are such that the early morning is not an optimal time.

But here's the hitch: what does this mean for parents and teachers?

School times are set largely for the convenience of parents and

teachers--not students. Will mom and dad now have to worry about how to

shuffle their kids to and from school at odd times? And will they

regret the endorsement of staying up to the wee hours on the morning

and sleeping in past the breakfast hour? What about the teachers? How

much longer of a day can they take?

Therein lies the need for a little experimentation with ideal times

and new demands on parents, administrators, and teachers. Maybe 11:30 is pushing it. And maybe changing the schedule won't really change kids' habits. They will still play with the limits and arrive groggy and cranky no matter what hour we ask them to get going. Students are chronically sleep deprived--it's the nature of the beast so to speak. As a sleep doctor, I applaud this school board in Toronto for exploring how to improve students' success. But as a parent, I should hope they work out all the details to accommodate such a huge shift.

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