There are two things adults envy about youngsters – their bountiful energy and their naps.
A new study says that those afternoon siestas that many preschoolers enjoy are not a waste of time. In fact, a daily nap may improve their ability to learn by improving their memory skills.
Preschooler’s brains are busy. On a daily basis they are processing new and exciting information. Their brains are storing the input from these experiences in short-term storage areas said Rebecca Spencer, lead study author and a neuroscientist at the University of Massachusetts, Amherst.
"A nap allows information to move from temporary storage to more permanent storage, from the hippocampus to the cortical areas of the brain," she said. "You've heard the phrase, 'You should sleep on it.' Well, that's what we're talking about: Children need to process some of the input from the day."
Many of the nation's preschoolers put in longer days than do their working parents, arriving at school as early as 6:30 a.m. and getting picked up after 5 p.m., Spencer said. "We're all short on sleep, and the kid's sleep is affected by the parents' schedules," she said.
For the study, the researchers taught 40 children from six preschools in western Massachusetts a visual-spatial memory game in the morning. The children were asked to remember where nine to 12 different pictures were located on a grid.
During the afternoon, children were either encouraged to nap or to stay awake. Naps lasted about 80 minutes. Later in the afternoon and the following morning, delayed recall was tested between both groups -- children who were encouraged to sleep and those who were kept awake.
The researchers found that although the children performed similarly in the morning, when their retention was fresh, children forgot significantly more when they had not taken a nap. Those who had slept remembered 10 percent more than those who were kept awake. The next day, the kids who had napped the previous afternoon scored better than those who hadn't napped. The data showed that a child doesn't recover the memory benefit from nighttime sleep, the researchers said.
To better understand whether memories were actively processed during naps, the researchers took 14 preschoolers to a sleep lab for polysomnography, a sleep study that shows changes in the brain. The children took naps for about 70 minutes. The napping children showed signs of signals being sent to long-term memory from the brain's hippocampus.
"Thus, there was evidence of a cause-and effect relationship between signs that the brain is integrating new information and the memory benefit of a nap," Spencer said.
The study was published in the September issue of the journal Proceedings of the National Academy of Sciences.
Spencer is concerned about the trend in many public preschools to discontinue naps. She said naps need to be put back into the preschool day, and she wants to see exploration of ways to enhance the napping experience -- with darkened rooms and comfortable cots or pads, for example.
What’s the bottom line? "Naps are not wasted time," Spencer said.