BBC Terrific Scientific Sleep Investigation reveals 9-11 year-olds react better in the afternoons

Published: 13 June 2017

Results were surprising in two ways: first that children slept longer after the clock change, and secondly their reaction time was faster in the afternoon than in the morning
— Doctor Katharina Wulff

Thousands of children from schools across the UK took part and data from 900 children was analysed
68 percent report feeling more of an ‘evening type’ - meaning they had more energy levels and higher alertness later in the day
Sleep time increased after the clock change in March 2017 by an average of 30 minutes
Sleepiness was greater in the morning than in the afternoon
Reaction times, on average, were faster in the afternoon and generally faster after the clock change
Many primary schools schedule maths and literacy lessons in the morning when they assume the children will be more awake to learning, which these findings may challenge

A BBC Terrific Scientific investigation, in partnership with the University of Oxford, into children’s sleep patterns following the clock change in March has discovered that surprisingly sleep time increased and sleepiness reduced, against expectations. The investigation also revealed that the children reacted quicker in the afternoon, irrespective of clock change.

BBC Terrific Scientific invited schools across the UK to keep a sleep diary for three days on either side of the clock change early in the morning of Sunday 26 March. Children from all around the country took part and they conducted a series of tests designed to measure both their tiredness and reaction times in the morning and afternoon.

The children’s results found that sleep time increased by an average of 30 minutes after the weekend. This is contrary to popular belief that you’d expect sleep time to decrease due to the clocks changing and effectively losing an hour’s sleep.

The sleepiness assessment indicated lower alertness in the morning than in the afternoon, which corresponds well with faster reaction times in the afternoon.

Interestingly, many primary schools schedule maths and literacy lessons in the morning when they assume the children will be more awake and open to learning, which these findings may challenge.

The investigation found that on average the children were sleeping over nine hours 30 minutes, which suggests the pupils are getting the recommended amount of sleep, which is between 9-11 hours. Following the clock change, researchers found the children woke up on average 10 minutes later in the morning, suggesting that they were compensating for the loss and this resulted in increased total sleep time.

With reaction times, on average the children were faster in the afternoon than the morning. They also felt less sleepy in the afternoon than in the morning. They reported feeling slightly more sleepy the morning after the clock change, probably due to the internal body clock lagging an hour behind the external time.

Doctors Katharina Wulff and Christopher-James Harvey from the University of Oxford analysed the data and helped designing the Time investigation.

Speaking about the result, Doctor Katharina Wulff says: “The Time Investigation has provided us with sleep and reaction time data of a large, representative sample of 9-11 year-old schoolchildren across the UK. Results were surprising in two ways - first that children slept longer after the clock change and secondly that their reaction time was faster in the afternoon than in the morning.

"The Time Investigation provides a great example of how schoolchildren can get directly involved in research and prove perceived public wisdom wrong.”

BBC Terrific Scientific also partnered with the Institute of Physics and Primary Science Quality Mark to deliver the resources for this investigation.

Notes to Editors
The investigation was unique in that it was time-bound to the clock change from GMT to BST in March 2017.

Children at schools across the UK were asked to keep a sleep diary for three days either side of the clock change early in the morning of Sunday 26 March.

Either side of the weekend they conducted a series of tests designed to measure both their tiredness and reaction times both in the morning and afternoon.

Schools were invited to submit the number of minutes sleep lost or gained by their children to the BBC’s interactive map of the UK and more detailed information about their sleep to the University of Oxford.

You can see the results on the BBC’s interactive map here

BBC Terrific Scientific is an exciting science project from the BBC, designed for 9-11 year-olds. It aims to inspire the next generation of budding scientists with engaging investigations in the classroom.

Through 10 investigations, each in line with different aspects of the curriculum, this initiative is hoping to increase children’s interest in science. Each investigation is partnered with a UK University who receive a large data set of results, collected by children across the UK. This data will feed into studies the Universities are already involved in, ranging from understanding the chemistry of water to carbon storage in UK trees.

11,000 classes from over 5,000 schools and hundreds of thousands of pupils are currently taking part in Terrific Scientific.

More information at www.bbc.co.uk/terrificscientific

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