TORONTO - As children try to get back into the groove at school, one thing is almost certain: sleep patterns will be a bit wonky as they adjust from late nights and leisurely mornings to earlier bedtimes and rise-and-shine wake-up calls.
Few people dispute the benefits of a good night's sleep when it comes to readiness to learn -- and two new studies released Saturday in the journal Sleep contribute to the body of research.
Dr. Jacques Montplaisir of the Sleep Disorders Centre at Sacre-Coeur Hospital in Montreal and his colleagues tracked close to 1,500 children from five months to six years of age, and their findings suggest that youngsters who got less sleep were more likely to have behavioural and cognitive problems in the classroom.
"The results of the paper highlight the importance of giving a child the opportunity to sleep at least 10 hours a night throughout childhood, especially before the age of 3 1/2 years, to ensure optimal cognitive performance'' on entering the school system, Montplaisir said in a statement.
And a study by Jan Van den Bulck in Leuven, Belgium, looked at an older cohort -- teenagers -- and found that the use of cellphones for calling and text messaging after lights out was prevalent. Only 38 per cent of the more than 1,600 teens studied said they never used their mobile phone after going to bed.
The study had several limitations -- for instance, it relied on self-reported data -- but suggests even moderate use of a cellphone after lights out raises the risk of long-term tiredness.
Dr. Colin Shapiro of the Youthdale Child and Adolescent Sleep Clinic in Toronto has read these latest studies and was involved in research on Ontario high school students a few years ago which found that, with some exceptions, "the longer you sleep the better your grades.''
"Sleep is not just a passive process, there are active things going on, you're metabolizing and putting out hormones and so on,'' Shapiro, a professor at the University of Toronto, said in an interview.
The Montreal study seems to fit with the growing literature that sleep is good for memory and good for brain growth, he said.
"They've shown that kids who have longer sleep have more cognitive skills, and so that probably means that one can infer that there's something about the sleep process that helps with cognitive development,'' he said.
"And so our attitude of making sleep expendable comes with a cost.''
He called the cellphone study from Belgium "straightforward.''
"One could have guessed that,'' he said of the after-bedtime phone calls and text messaging by teens. "They've documented it, but it's an important issue ... you've got to recognize that sleep is a valuable part of life and you need to have a time that you're not disturbed in your sleep.''
"Certainly having your cellphone as a potential disruptor because you have to be in touch with everyone all the time is a mistake. It's not going to lead to good function.''
Cellphones, text messages a late-night distraction
Chaya Kulkarni, a Toronto educator with the organization Invest in Kids, said the use of mobile phones after lights out would be a concern for her as a parent.
"What's to stop a child from staying up until 2 in the morning, texting their friends, having nice long conversations ... You have to have some rules in place,'' said Kulkarni, the mother of tweens aged nine and almost 12 who aren't yet equipped with cellphones.
As for back to school, Shapiro says it's relatively easy to allow one's sleep pattern to go later, but to make it go earlier after a weekend or a summer vacation is not so easy.
"This is particularly because the biological clock is longer than the 24-hour day, and it's normally just synchronized into a 24-hour day because of bright lights and the sunshine,'' he said.
"In some students they just power through it and they say `OK I have to make that adaptation.' They become a little bit sleep-deprived and try and catch up with that sleep on the weekend.''
However, some students can't do that and are late for school or, in extreme cases, don't get to school at all, he said.
"They're often accused of, for lack of a better expression, being bloody-minded _ they want to just watch TV and be on their GameBoy and involved with e-mailing their friends and, as this one article suggests, phoning their friends late at night,'' he said.
"Although those are significant issues, for some of them it is simply biologically driven.'' He noted, by comparison, that "teenage monkeys go to bed late and get up late.''
"When it is a body clock problem, it's usually because their melatonin secretions, which controls the body clock, is coming out later than it would normally for younger kids or for adults. And for some of them, they need a treatment that helps them to adjust the body clock.''
Kulkarni says that for younger kids, even if a family hasn't started the transition to earlier schoolyear bedtimes, it's not too late.
"I think what's important here is that you establish a routine for bedtime with the children that is going to be workable for everybody with the start of school,'' she advised.
"So whether that's baths at 7:30 followed by a storytime, but you know, an easing into a quiet time and sort of toning it down.''
She also recommends a morning routine so that everyone can get out of the house on time.
"The adults in the family need to confer and need to say `OK, what's every day going to look like, and who's doing what?''' she said.
"Sort out roles and responsibilities in terms of those morning and evening routines so that at the very least, on Tuesday or whenever the kids start, you're not sort of looking at each other going `Oh I thought you were doing that.'''
