Napping is practically essential for preschool-age children, but now a new study published in the journal SLEEP shows that older kids ages 10 to 12 can also benefit significantly from taking naps.
A research team from the University of Pennsylvania and the University of California, Irvine, evaluated nearly 3,000 Chinese students in 4th, 5th, and 6th grade and found a link between midday napping and greater happiness, self-control, and grit; fewer behavioral problems; and higher IQ, the latter particularly for the sixth graders.
The most robust findings were associated with academic achievement, said co-author Dr. Adrian Raine, a Penn neurocriminologist.
“Children who napped three or more times per week benefit from a 7.6 percent increase in academic performance in Grade 6,” he says. “How many kids at school would not want their scores to go up by 7.6 points out of 100?”
Sleep deficiency and daytime drowsiness are surprisingly widespread, with drowsiness affecting up to 20 percent of all children, said lead author Dr. Jianghong Liu, a Penn associate professor of nursing and public health.
The negative cognitive, emotional, and physical effects of poor sleep habits are well-established, and yet most previous research has focused on preschool age and younger. That’s partially because in places like the United States, napping stops altogether as children get older. In China, however, the practice is included in daily life, continuing through elementary and middle school, even into adulthood.
So, Liu and Raine, with Penn biostatistician Rui Feng, UC Irvine sleep researcher Sara Mednick and others, turned to the China Jintan Cohort Study, established in 2004, to follow 2,928 participants from toddlerhood through adolescence.
The researchers collected data about napping frequency and duration once the children hit Grades 4 through 6, as well as outcome data when they reached Grade 6, including psychological measures like grit and happiness and physical measures such as body mass index and glucose levels. Teachers were also asked to provide behavioral and academic information about each student.
The researchers then analyzed 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, 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 behavioral, academic, social, and physiological measures,” Mednick said.
Predictably, she added, “the more students sleep during the day, the greater the benefit of naps on many of these measures.”
Though the findings don’t prove cause-and-effect, the researchers said they may offer an alternative to the outcry from pediatricians and public health officials for later school start times.
“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.”
