The Science of Sleep: How Much Does Your Child Really Need?Heather Turgeon
My five-year-old started kindergarten this week. The low-key summer — which he spent digging in dirt and running through sprinklers — is over, and we’re officially on a new, more structured back-to-school schedule.
Like many parents, I know my kid’s sleep affects not just his mood and energy, but also his ability to think clearly, remember, and learn. We tend to think of sleep as a time of rest or the body’s “off mode,” but it’s not really; it’s a busy, active time when growth hormones are secreted and connections between brain cells are strengthened. Kids can do the basics when they’re tired — eat, talk, run around — but sophisticated thinking and concentration takes a big hit, even with just a modest decrease in sleep.
In one study, researchers saw that when sixth graders slept just one hour less per night, they performed like the average fourth grader on neurobiological tests (tests that are good predictors of achievement and classroom behavior). Another experiment showed that just 27 minutes more of sleep made a significant improvement in how restless, impulsive, and moody children were. Restricting their sleep by 50 minutes had the opposite effect.
So given the connection between sleep and school, productivity, and happiness, exactly how much shut-eye does your child need? And — beyond the simple number tally — how can you tell if your child is really getting enough?
To start, here’s what researchers and sleep experts agree are recommended sleep times for the whole family. Keep in mind that the numbers refer to actual sleep, not just time spent in bed. It can take young children a long time to wind down, so if yours gets into bed at 7:30 p.m. but doesn’t drift off till 8:00 p.m., that’s when the clock actually starts.
Age and Sleep Needs
Newborns: 12-18 hours
Infants (3-11 months): 14-15 hours
Toddlers (1-3 years): 12-14 hours
Preschoolers (3-5 years): 11-13 hours
Children (5-10): 10-11 hours
Teens (10-17): 8.5-9.25 hours
Adults: 7-9 hours
Where do these recommendations come from? They’re made from putting together data on optimal sleep (through studies of extended and shortened sleep durations) and also considering how much sleep kids actually get. Not surprisingly, there’s a difference between kids’ optimal and actual sleep patterns — the former being the better benchmark.
Notice that sleep recommendations are given as a range, not a magic number —that’s because kids vary slightly in the amount their bodies need. The same applies to adults: I personally need 8 hours of sleep to feel in top shape, but my husband seems to do well with 7 or 7.5. Our biological makeup gives us slightly different sleep needs, but checking your child’s sleep against the range of recommended hours is a good first step.
If your little one falls outside the range and you’re wondering whether he’s an exception (“he just doesn’t seem tired!”), it’s possible, but not likely. Taking adults as an example, it’s estimated that between one and three percent legitimately need less sleep than the norm, and it’s been suggested that out of every 100 people who believe they are “short sleepers,” only five actually are. Chances are, if your child seems fine on less sleep, he would do even better with 30-60 minutes more.
Just hitting the numbers isn’t enough, though. Assuming your child falls in the right range, his behaviors are now your strongest clues to gauge how well-rested he is. It’s rare for children to yawn, stretch, and tell you they’re ready for bed (red flag if they do — that usually means overtired), so here’s what to look for. These are the telltale signs of a rested child, versus a sleep-deprived one.
Well-rested kids typically:
Wake up naturally
Are alert most of the day or until their scheduled naptime
Do not fall asleep in the stroller or car in between naps
Have the same sleep schedule on weekdays and weekends
Have the same nap habits at school and home
Kids who need more sleep typically:
Need to be woken up in the morning
Are hyperactive, inattentive, or moody
Fall asleep in the car or stroller before scheduled naptimes
Sleep in on the weekends, or
Fall asleep in school outside of a regular naptime.
Don’t worry if your child has some characteristically sleepy signs off and on. Kids accumulate subtle “sleep debt” just like adults, so taking an extra long nap, nodding off in the car, or sleeping in on a Saturday morning once in a while are all ways of catching up and paying that sleep debt back. The problem is that sleep is somewhat flexible: a three-hour nap on Sunday might compensate for staying up to watch a movie on Saturday. But the fact remains that our kids’ circadian rhythms thrive on regularity, and they’re happiest when they keep to roughly the same schedule of activity and rest.
It doesn’t mean you can’t bend the rules every so often. Even in our house (notorious for early-bird sleep practices), we bend. We eat out on Friday nights, which can lead to missed bedtimes, sometimes my one-year-old’s nap has to fit around the family’s activities, and on special occasions like holidays, we have to be flexible as well. In an exciting social setting, my kids, like many, actually don’t turn into pumpkins when their bedtime nears — they party until we get home, at which time their tiny bodies collapse.
Still, I can see that less-than-optimal sleep affects their mood, and even when I can’t see it, below the surface I know it tugs on their creativity and critical-thinking skills. Just like food, top-notch sleep is one of the basics. When it’s off, it’s like a crack in the foundation. When it’s on track, your child is starting the day from a better, smarter, happier place.