What does the research say about sleep?

23 March 2017

Author: Jonathan Haslam

“Wake up, Alice dear!” said her sister; “Why, what a long sleep you’ve had!” “Oh, I’ve had such a curious dream!” said Alice.

Lewis Carroll, Alice’s Adventures in Wonderland

Twitter is a great leveller. It gives anyone the opportunity to comment on anything. And so, this week, The Honourable Kirstie Allsopp gave her views on children and sleep.


I don’t know where Kirstie got this number from, but it doesn’t seem to be supported by the research.

The National Sleep Foundation in the US conducted a systematic literature review that provided recommendations for hours of sleep across the ages, summarised in this neat infographic:


Hirshkowitz M, The National Sleep Foundation’s sleep time duration recommendations: methodology and results summary, Sleep Health (2015) http://dx.doi.org/10.1016/j.sleh.2014.12.010

(Frankly, I was hoping to increase the amount I sleep as I get older, but this looks unlikely to happen.)

While schools are clearly unable to control the amount of sleep that children, or staff, get, I think it helps to be aware of the recommendations, in case you are asked for guidance.

There is other research on sleep times for children that may also be of interest:

Younger children

Young children benefit from regular bedtimes – Irregular bedtimes at age three were linked with lower cognitive test scores. The effects were cumulative, so irregular bedtimes at three, five and seven had more impact. The irregular bedtimes might be a consequence of a chaotic family environment, but the researchers tried to control for this.

Sleep problems in early childhood – Parents may be concerned about young children who struggle to sleep. This Australian study showed that for most children, sleep problems reduce from birth to five years. Those children who experience escalating sleep problems throughout early childhood may struggle to settle at school, and may benefit from intervention.

An early start may not be good for young children – While the negative impact of an early start on teenagers is well known, there has been little research on the impact on younger children. This study in Kentucky found that an earlier start time also affected school performance in elementary (primary) school, at least for better-off children. The start times ranged from 7am to 9am.

Older children

It is well known that teenagers have a different biological sleep cycle from younger children. They are primed to stay up late, and wake up late too. In 2014, the American Academy of Pediatrics (AAP) recommended that secondary schools start no earlier than 8.30am. Researchers from Harvard University, Oxford University and the University of Nevada have advised 10am for 16-year-olds and 11am for 18-year-olds.

The impact of later start times was shown in this study in Minnesota, which found that schools with start times after 8.35am showed significantly better academic outcomes, as well as a reduction in the number of car crashes involving young drivers.

It seems, too, that there may be a conflict between the amount of sleep needed for the best mental health, and the amount needed for academic success. This study showed that there were optimum sleep times for academic success, and that these fell from 9-9.5 hours for 10-year-olds to 7 hours for 16-year-olds. A recent study of children aged 14-16 in Los Angeles found that 9 hours sleep was best for mental health, with 7-7.5 hours best for academic success.

Before we blame it all on their hormones, this study found that, for teenagers, sleep disturbance was usually caused by traumatic social events (whether within their family or at school). Feeling part of the school they attended and being surrounded by academically oriented and prosocial friends was the best medicine.

And, finally, Kirstie may have a point about electronic devices. This research found that increased parental monitoring of children aged 8-11 and their use of media led to reduced screen time, which in turn led to better quality sleep.

Posted on 23 March 2017
Posted in: Blog

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