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.