There's no single trick for getting toddlers and pre-schoolers to nap, and it's possible that some children who resist sleeping during the day are getting all the rest they need at night.
How naps impact sleep
Tackling a topic that has long baffled parents of young children, a team of Australian researchers reviewed 26 previously published studies on how naps impact sleep at night, as well as learning and behaviour during the day. It may come as no surprise to parents that researchers found little consensus beyond the fact that after age two, kids who nap may not sleep as much at night.
"The study doesn't imply you shouldn't let your kids nap," said Jodi Mindell, associate director of the sleep centre at The Children's Hospital of Philadelphia. "There are only so many hours a day that you can sleep, but that doesn't mean that napping leads to poor sleep."
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By age two, many children should be sleeping during the night for about 10 to 11 hours, and getting about one to three hours during the day, said Mindell, who wasn't involved in the study.
Children who take long naps, and still have no difficulty falling asleep at bedtime or waking up on their own in the morning, are probably getting the right amount of rest, she said.
Several of the studies the Australian researchers reviewed focused on the relationship between naps and sleep at night. The analysis found links between naps and later bedtimes, shorter periods of sleep at night, and waking up more often during the night.
Kids go to sleep later after naps
One study of kindergarten students who had an optional nap period found that kids went to bed later after a nap than without a nap during the day.
The relationship between napping and developmental outcomes is less clear, the study team writes in the Archives of Disease in Childhood.
Some studies suggested that napping aided language learning, but others found the opposite.
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Anxiety and worry appeared more common in children who didn't nap, some studies found, but other research suggested a link between longer naps and children acting more withdrawn or depressed.
None of the studies can prove cause and effect, however. Because they were "observational" in design, and didn't randomise groups of children to take or skip naps, more experiments are still needed to understand how naps impact sleep and development, the researchers note.
A lot of the studies were also based on observation at a single point in time, said Dr. Judith Owens, director of the Centre for Paediatric Sleep Disorders at Boston Children's Hospital, "so you don't know if the kids stopped napping because they're getting more sleep at night or if you had a child who was a regular napper and you suddenly took the nap away before they were ready."
Parents shouldn't focus on numbers
When it comes to naps, parents shouldn't focus so much on the numbers, said Owens, who wasn't involved in the new study. Instead, they should pay attention to how their child behaves.
If for example, your child sleeps 10 hours during the week and 11 hours on the weekends, that probably means they aren't getting enough sleep, Owens said. Or, if your child often nods off in the car or while watching cartoons or movies, that's another sign they need more sleep.
A well-rested child will wake up on their own without an alarm clock, she added.
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For toddlers or pre-schoolers who still need naps, they might need to nap earlier in the afternoon to avoid delaying bedtime at night so they get enough total hours of sleep in a 24-hour period, Owens said.
"I encourage parents to know in general what the recommendations are for amounts of sleep for kids at different ages, but then really be cognizant of the other clues from each of their children that may tell them what approach is best," Owens said.
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Image: Yawning boy from Shutterstock