Does your toddler have a difficult time getting to sleep most nights? It could be that his or her body clock isn’t in sync with bedtime. The body has a natural sleep and wake cycle called a circadian rhythm. It’s like a master biological clock that lets us know when to be alert and when to sleep. When our body clock gets out of sync with our real time sleep and alertness needs, we have trouble falling asleep or staying awake when we need to.
But how does that clock work in preschoolers, who need more sleep than older kids or adults? A first-of-its-kind study tracked 14 healthy youngsters for six days to begin finding out.
The children, ages 2½ to 3, wore activity monitors on their wrists to detect when they slept and the parents kept diaries of their children’s bedtime routines.
Then on the last afternoon, researchers visited each home, dimming lights and covering windows. Then every 30 minutes for six hours leading up to the child’s appointed bedtime, they also coaxed each tot to chew on some dental cotton to provide a sample of saliva.
The saliva was used to test for the hormone, melatonin. Melatonin helps control our sleep and wake cycles. It’s made by the pineal gland in the brain. Light affects how much melatonin the body produces. During the evening hours melatonin levels start to increase causing you to get sleepy.
‘‘Just like nutrition and exercise, sleep is critical for good health,’’ said sleep scientist Monique LeBourgeois of the University of Colorado, Boulder, who is leading the research.
For preschoolers, the new study found that on average, the melatonin surge occurred around 7:40 p.m. The children tended to be tucked in around 8:10 p.m., and most were asleep 30 minutes later, LeBourgeois reported in the journal Mind, Brain and Education.
When melatonin rose earlier in the evening, tots who hit the sack around 8 fell asleep a bit faster. But when the melatonin surge was closer to bedtime, the youngsters were more likely to fuss or make curtain calls after lights-out.
Two children in the study actually were tucked in before their rise in melatonin ever occurred, and it took them up to an hour past bedtime to fall asleep, she said.
Other factors can also have an impact on children’s ability to fall asleep such as loud noises, stress or anxiety or disrupted home routines.
The National Institutes of Health says preschoolers need 11 to 12 hours of sleep each day; some typically comes from an afternoon nap.
About 25 percent of young children experience some type of sleep difficulty, including trouble settling down at bedtime, LeBourgeois said. Harried parents aside, there’s concern that early-in-life bedtime frustration might lead to more persistent sleep trouble.
‘‘Listen to your child’s physiology,’’ she advised. She offers these steps to help your child fall asleep faster.
- Too much light in the evening delays the melatonin surge and subsequent sleepiness. While there’s no data in young children yet, LeBourgeois says dimming the lights about an hour before bedtime makes sense.
—Avoid electronics near bedtime, because they generate a specific type of light that triggers wakefulness. LeBourgeois was horrified to hear that one parent offer a sleepless youngster an iPad to play with as long as the child stayed in the bedroom.
—And make sure blackout shades aren’t keeping your children from getting enough morning sunlight, she said. Light in the morning also is key to keeping the biological sleep clock on schedule. If your child’s bedroom needs blackout shades to make it dark enough at night, go in early and open the shades before your child needs to wake up.
More studies are planned to help track sleep patterns in toddlers. There’s no exact “sweet spot” that’s been found to guide parents on when to put their little one to bed…yet.
But, by watching your toddlers physical behavior as the evening progresses and offering a quite and calm environment with less light, you should be able to see what works best.