Sleep and cognition in children

  • A U.S. survey provides evidence that both children and adolescents tend to be getting less sleep than needed.
  • Depression, lower self-esteem, and lower grades, have all been found to be correlated with sleep deprivation in middle-school children.
  • Sleep disturbance in infants and young children has also been found to be associated with lower cognitive performance.

We all know that lack of sleep makes us more prone to attentional failures, more likely to make mistakes, makes new information harder to learn, old information harder to retrieve ... We all know that, right? And yet, so many of us still go to bed too late to get the sleep we need to function well. Of course, some of us go to sleep early enough, we just can’t get to sleep fast enough, or are prone to waking in the night. (Personally, I can count the times I’ve slept through the night without waking in the last fifteen years on my fingers).

I talk about the effect of sleep on memory elsewhere; I want to talk here about a sleep problem that we don’t tend to think about so much — the sleep deficit children are running.

A survey commissioned by the National Sleep Foundation found that 3-to-6-year-olds in the U.S. get about 10.4 hours sleep nightly, while experts recommend 11 to 13 hours. 1st graders to 5th graders who should be getting 10 to 11 hours are averaging just 9.5 hours.

And a study of middle-school children (11 to 14 year olds) found a direct correlation between sleep deprivation and depression, lower self-esteem, and lower grades. "The fewer hours of sleep that children got, the more depressed they were, the higher number of depressive symptoms [they had], and the lower their self-esteem and the lower their grades."

The second largest growth spurt occurs during these years (usually 10-14 for girls; 11-16 for boys), so this is a time when a lot of sleep is needed. But it’s also a time when children become more capable and more independent; when they’re likely to start taking on a lot more activities, work harder and longer, and are monitored less by their parents and caregivers. So ... it’s not surprising, when we stop and think about it, that a lot of these children are starting to pick up the bad habits of their parents — not getting enough sleep.

Which also points, in part, to the solution: if you’re a parent, remember that your children are, as always, modeling themselves on you. And sleep habits usually reflect a household pattern. If you’re a teacher, remember you need to educate the family, not just the child.

The National Institutes of Health (NIH) have identified adolescents and young adults (ages 12 to 25 years) as a population at high risk for problem sleepiness based on "evidence that the prevalence of problem sleepiness is high and increasing with particularly serious consequences."

Sleep disturbance in infants and young children has also been found to be associated with lower cognitive performance. Previous studies have looked at the severe end of the spectrum of sleep disorders — obstructive sleep apnea. More alarmingly, a new study of 205 5-year-old children found even mild sleep-disordered breathing symptoms (frequent snoring, loud or noisy breathing during sleep) were associated with poorer executive function and memory skills and lower general intelligence.

Before you panic, please note that some 30% of the participants had SBD symptoms, so it’s hardly uncommon (although there may have been a bias towards children with these symptoms; it does seem surprisingly high). You might also like to note that I personally had a blocked nose my entire childhood (always breathed through my mouth, and yes, of course I snored) and it didn’t stop me being top of the class, so ...

Nor is the research yet developed enough to know precisely what the connection is between SBD and cognitive impairment. However, it does seem that, if something can be done about the problem, it is probably worth doing (in my case, taking me off dairy would probably have fixed the problem! but of course noone had any idea of such factors back then).

Here’s a few links that may be of interest to parents and teachers:

The NSF Sleep poll

a look at the school start times debate (I find this fairly amazing actually, because here in New Zealand, our children usually start school around 9am; the thought of kids starting school at 7.30 sends me into a spin!)

The National Sleep Foundation also has a site for children who want to learn about sleep and healthy sleep habits: For children from 7 up; with educational games and activities, as well as a downloadable copy of NSF’s new Sleep Diary designed especially for children.

This article originally appeared in the November 2004 newsletter.