Washington DC [USA], Jun 1 : Researchers from the University of Pennsylvania and the University of California, Irvine, have revealed a connection between midday napping and happiness, self-control, and grit; fewer behavioural problems; and higher IQ, in children.
The research published in the journal 'Sleep' studied nearly 3,000 fourth, fifth, and sixth graders of ages 10-12.
"Children who napped three or more times per week benefit from a 7.6 per cent increase in academic performance in grade six," said Adrian Raine, Penn neurocriminologist, a co-author on the paper.
Sleep deficiency and daytime drowsiness are surprisingly widespread, with drowsiness affecting up to 20 per cent of all children, said Jianghong Liu, lead author of the study.
What's more, the negative cognitive, emotional, and physical effects of poor sleep habits are well-established, and yet most previous research has focused on preschoolers and younger children.
That's partly because, in places like the United States, napping stops altogether as children get older. In China, however, the practice is embedded in daily life, continuing through elementary and middle school, even into adulthood.
So, the researchers turned to the China Jintan Cohort Study, established in 2004 to follow participants from toddlerhood through adolescence.
From each of 2,928 children, the researchers collected data about napping frequency and duration once the children hit grades four through six, as well as outcome data when they reached grade six, including psychological measures like grit and happiness and physical measures such as body mass index and glucose levels.
They also asked teachers to provide behavioural and academic information about each student. They then analysed associations between each outcome and napping, adjusting for sex, grade, school location, parental education, and nightly time in bed.
It was the first comprehensive study of its kind, UC Irvine sleep researcher Sara Mednick said.
"Many lab studies across all ages have demonstrated that naps can show the same magnitude of improvement as a full night of sleep on discrete cognitive tasks. Here, we had the chance to ask real-world, adolescent schoolchildren questions across a wide range of behavioural, academic, social, and physiological measures," she added.
"The more students sleep during the day, the greater the benefit of naps on many of these measures," she said.
"The midday nap is easily implemented, and it costs nothing," said Liu, particularly if accompanied by a slightly later end to the day, to avoid cutting into educational time.
"Not only will this help the kids, but it also takes away time for screen use, which is related to a lot of mixed outcomes," Liu added.