A regular bedtime might guarantee more than a good night's sleep for both kids and their parents -- it turns out that a regular bedtime can make for a better-behaved child, new research suggests.
When 7-year-olds had irregular bedtimes, they were more likely to have behavior problems than their peers with a consistent time for their nightly shut-eye. And, the study also found that the longer a child had been able to go to bed at different times each night, the worse his or her behavior problems were.
"Irregular bedtimes were linked to behavioral difficulties, and these effects appeared to accumulate through early childhood," said the study's lead author, Yvonne Kelly, a professor of lifecourse epidemiology at University College London.
"We also found that the effects appeared to be reversible -- children who changed from not having, to having, regular bedtimes showed improvements in behaviors, and vice versa," she added.
Kelly and her colleagues reviewed data on more than 10,000 7-year-olds who were enrolled in the U.K. Millennium Cohort Study. Details on the children's bedtimes were collected when they were 3, 5 and 7 years old.
At the same time that sleep findings were collected, researchers asked teachers and mothers to rate the children's behaviors. The behavior survey included 25 questions.
Kids with irregular bedtimes had more behavioral problems than did children with regular bedtimes, according to both their teachers and their mothers. The children's mothers rated the children with irregular bedtimes as having slightly more behavior problems than did the teachers.
The longer a child had an irregular bedtime, the greater the behavioral difficulties. On average, a child who had an irregular bedtime at one time-point in the study increased his or her score on the behavioral difficulties scale by about a half-point. If that child had an irregular bedtime at two time-points during the study, the score increased by about 1 point. If the child had an irregular bedtime at all three time-points during the study, the score increased by just over 2 points.
"A half-point corresponds to a 'small' effect. Irregular bedtimes at two ages, and all three ages, corresponded to a 1- and 2-point difference in behavior scores. These effect sizes would have 'moderate' clinical significance," said Kelly when asked if these score differences would make a noticeable difference in a child's behavior.
The good news from the study is that if you switch your child to a regular bedtime from an irregular bedtime schedule, your child's behavior will likely improve. The reverse is also true. If a child with a regular bedtime switches to an irregular one, behavior will likely worsen, the researchers noted.
Kelly said irregular bedtimes could contribute to behavior problems in several ways. "First, switching bedtimes from night to night interferes with circadian rhythms [the body clock] and induces a state akin to jet lag. Second, disrupted sleep interferes with processes to do with brain maturation," she explained.
Dr. Ruby Roy, a pediatrician at La Rabida Children's Hospital in Chicago, agreed that several reasons may contribute to a connection between irregular bedtimes and behavior problems.
"When kids don't have structure and predictability, they have anxiety," Roy said. "Kids naturally want to push boundaries, and when they don't have boundaries, it causes anxiety and acting out. A lack of sleep can also cause behavior problems, and some of these kids may only be going to sleep when they're passing out from exhaustion, which means they won't get enough sleep," she explained.
"Kids probably sleep better with regular bedtimes and when they have established bedtime routines," Roy added.
Kelly concluded: "Getting regular routines around bedtimes appears to be important for children's behavioral development. But, there are lots of other influential factors, too. So we shouldn't get too hung up about children having the same bedtime every single night."
The study was published online Oct. 14 and in the November print issue of the journal Pediatrics.
Here's some advice on bedtime routines from the American Academy of Pediatrics.