Book: Nurture Shock – Review

Nurtureshock: Why Everything We Thought About Children is Wrong – Po Bronson and Ashley Merryman

This review is only about Chapter 2, since that is about sleep, which is the subject of my current project. The other chapters are equally interesting though! In the chapter ‘The Lost Hour’, the authors describe how children today sleep one hour less than they did 30 years ago and how that impacts their wellbeing.

Like in several scientific papers I read on this subject, it is stated here that a high percentage of high-schoolers feel sleepy during school, their grades drop because of that, and some fall asleep in class. They go as far as to say that the average amount of sleep a child in high school gets, is only 6,5 hours!

The causes for this lack of sleep are the usual suspects: full schedules, early school start times, adolescent circadian clock shifts. Not much time is spend describing possible solutions for this lack of sleep, other than that teenagers who went to bed earlier, got more sleep; their IQ went up and so did their grades. But how to motivate teenagers to go to bed early?

Then an interesting part about adolescents. For reference, I looked up the definition of adolescence in several sources. I was disappointed to find no watertight definition of it, other than some rather vague descriptions without much overlap. The World Health Organisation defines adolescence as the period between 10 and 20 years of age. In the US, adolescent age is often defined as between 13 and 24.

Brown’s Mary Carskadon has demonstrated that during puberty, the circadian system – the biological clock – does a ‘phase shift’ that keeps adolescents up later. In prepubescents and grownups, when it gets dark outside, the brain produces melatonin, which makes us sleepy, But adolescent brains don’t release melatonin for another 90 minutes. So even if teenagers are in bed at 10 p.m. (which they aren’t), they lie awake, staring at the ceiling.

Several experiments with pushing back school start times and letting teens sleep longer, have yielded better results on SAT tests. And interestingly, also typical modern puberescent behaviours like moodiness, depression and binge eating go down with more sleep. Could it be that todays teenagers act out more because of their lack of sleep? The authors of Nurtureshock certainly believe so.

Another side effect of sleep deprivation is an increased chance of becoming obese. Hormone levels change with sleep loss, increasing the feeling of hunger and favouring storage of fat. Furthermore, when you sleep less, you are tired during the day, so you are less likely to have an active lifestyle on top of being hungry. Plus, when you are asleep, you are not eating!

For my research, physical health could be an interesting aspect to define benefits of the proposed nap with. Next to factors like daytime sleepiness, moodiness and cognitive abilities, physical health is important. It would be good to incorporate some measure of that, be it weight, blood pressure or resting heart rate.

Advertisements

The influence of sleep on school performance – Review

Julia F. Dewald, Anne M. Meijer, Frans J. Oort, Gerard A. Kerkhof, Susan M. Bögels The influence of sleep quality, sleep duration and sleepiness on school performance in children and adolescents: A meta-analytic review Sleep Medicine Reviews, Volume 14, Issue 3, June 2010, Pages 179–189 http://dx.doi.org/10.1016/j.smrv.2009.10.004

This paper is a meta-analysis of the relation between sleep and school performance. Meta-analysis is a statistical method combining different study results. It enables the discovery of consistencies in a set of seemingly inconsistent findings.

Sleeping well is important for children and adolescents, since it influences learning and other memory processes.

insufficient or low quality sleep during (early) adolescence impairs the executive function of the prefrontal cortex16 and consequently the decline of learning abilities and school performance. [17] and [*18]

Sleep is crucial for children and adolescents’ learning, memory processes and school performance. [*1],[*2] and [*3]but 45% of children are not getting enough [7] and [8]. On average, adolescents need 9 hours of sleep per night. But as sleep quality is more important than sleep duration, more effective to measure is sleepiness, as this relates directly to enough sleep or not. If a child would sleep 8 hours a night and would not be sleepy during the day, their school performance would not suffer, in contrast to someone who could sleep 9 hours and still be sleepy in school.

Insufficient sleep might be caused by an interaction of intrinsic (e.g., puberty, circadian or homeostatic changes) and extrinsic factors (e.g., early school start times, social pressure, academic workload) leading to later bedtimes while getting up times remain unchanged. Additionally, it is known that approximately 20–50% of children and adolescents report daytime sleepiness. [9] and [10]

We see that daytime sleepiness is highest among children in mid-puberty. This makes me wonder what age group mid-puberty is exactly, so more about that later. The ages of mid-puberty also differ between boys and girls.

mid-pubertal adolescents may need more sleep than younger or older adolescents in order to reach the same level of daytime alertness and neurocognitive functioning. [*2][*16] and [24]

The article ends with a short summary, which is nice to remember where to focus:

Poor sleep quality, insufficient sleep and sleepiness are significantly associated with worse school performance.
We recommend educating children, adolescents, parents and schools about the importance of sleep for school performance. As part of this, education about sleep hygiene can be given in order to improves the sleep of children and adolescent and consequently school performance.
Attention should be drawn to the development of prevention and treatment programs that focus on the sleep of children and adolescents

For more literature on sleep, see this post.