Growth Curve | Science News

Be a Champion for Science

Get your subscription to

Science News when you join.

Growth Curve

The inexact science of raising kids

Laura Sanders

Growth Curve

Growth Curve

Long naps lead to less night sleep for toddlers

toddler napping

SNOOZE NOW OR LATER  Late afternoon naps can push back bedtime, but naps probably don’t affect the total amount of sleep a toddler gets in a 24-hour period, a study suggests.

Sponsor Message

Like most moms and dads, my time in the post-baby throes of sleep deprivation is a hazy memory. But I do remember feeling instant rage upon hearing a popular piece of advice for how to get my little one some shut-eye: “sleep begets sleep.” The rule’s reasoning is unassailable: To get some sleep, my baby just had to get some sleep. Oh. So helpful. Thank you, lady in the post office and entire Internet.

So I admit to feeling some satisfaction when I came across a study that found an exception to the “sleep begets sleep” rule. The study quite reasonably suggests there is a finite amount of sleep to be had, at least for the 50 Japanese 19-month-olds tracked by researchers.

The researchers used activity monitors to record a week’s worth of babies’ daytime naps, nighttime sleep and activity patterns. The results, published June 9, 2016, in Scientific Reports, showed a trade-off between naps and night sleep. Naps came at the expense of night sleep: The longer the nap, the shorter the night sleep, the researchers found. And naps that stretched late into the afternoon seemed to push back bedtime.

In this study, naps didn’t affect the total amount of sleep each child got. Instead, the distribution of sleep across day and night changed. That means you probably can’t tinker with your toddler’s nap schedule without also tinkering with her nighttime sleep. In a way, that’s reassuring: It makes it harder to screw up the nap in a way that leads to a sleep-deprived child. If daytime sleep is lacking, your child will probably make up for it at night.

A sleeping child looks blissfully relaxed, but beneath that quiet exterior, the body is doing some incredible work. New concepts and vocabulary get stitched into the brain. The immune system hones its ability to bust germs. And limbs literally stretch. Babies grew longer in the four days right after they slept more than normal, scientists reported in Sleep in 2011. Scientists don’t yet know if this important work happens selectively during naps or night sleep.

Right now, both my 4-year-old and 2-year-old take post-lunch naps (and on the absolute best of days, those naps occur in glorious tandem). Their siestas probably push their bedtimes back a bit. But that’s OK with all of us. Long spring and summer days make it hard for my girls to go to sleep at 7:30 p.m. anyway. The times I’ve optimistically tried an early bedtime, my younger daughter insists I look out the window to see the obvious: “The sky is awake, Mommy.”

Human Development,, Health

Evidence is lacking that ‘cocooning’ prevents whooping cough in newborns

By Laura Sanders 7:00am, April 20, 2017
In general, vaccinating adults who come into close contact with newborns is a good idea, but the practice on its own may not keep whooping cough away.
Human Development,, Health

Vaccinating pregnant women protects newborns from whooping cough

By Laura Sanders 9:00am, April 12, 2017
Pregnant women who receive the pertussis, or whooping cough, vaccine pass on to their new-borns immunity to the potentially deadly bacterial infection.
Human Development,, Health

Language heard, but never spoken, by young babies bestows a hidden benefit

By Laura Sanders 2:00pm, April 5, 2017
Adults who as babies heard but never spoke Korean benefited from their latent language knowledge decades later, a new study finds.
Human Development,, Health

For kids, daily juice probably won’t pack on the pounds

By Laura Sanders 7:00am, March 30, 2017
An analysis of existing studies suggests that regular juice drinking isn’t linked to much weight gain in kids.
Health,, Human Development

Don’t put greasy Q-tips up your kid’s nose, and other nosebleed advice

By Laura Sanders 7:00am, March 28, 2017
Nosebleeds in children are common and usually nothing to fret about.
Human Development,, Health

Touches early in life may make a big impact on newborn babies’ brains

By Laura Sanders 12:30pm, March 22, 2017
The type and amount of touches a newborn baby gets in the first days of life may shape later responses to touch perception, a study suggests.
Human Development,, Health

See how bacterial blood infections in young kids plummeted after vaccines

By Laura Sanders 3:39pm, March 15, 2017
Rates of pneumococcal bacteremia in children plummeted by 95 percent after the introduction of vaccines against Streptococcus bacteria.
Human Development,, Health

Anesthesia for youngsters is a tricky calculation

By Laura Sanders 9:00am, March 6, 2017
Scientists, doctors and parents face uncertainty when it comes to anesthesia for babies.
Human Development,, Health

A preschooler’s bubbly personality may rub off on friends

By Laura Sanders 8:00am, February 23, 2017
Scientists caught personality shifts in preschoolers over a year by observing play.
Human Development,, Health

Birth may not be a major microbe delivery event for babies

By Laura Sanders 12:13pm, February 15, 2017
A study of mother-baby duos suggests that birth itself may not be the main event for getting microbes in and on babies.
Subscribe to RSS - Growth Curve