Children who do not go to bed at a regular time may be more likely to exhibit behavior problems during the day.

Researchers found irregular bedtimes often "disrupt normal body rhythms" and can cause sleep deprivation which would make the child more likely to act out, a University College London news release reported. 

 "Not having fixed bedtimes, accompanied by a constant sense of flux, induces a state of body and mind akin to jet lag and this matters for healthy development and daily functioning," Professor Yvonne Kelly of UCL Epidemiology & Public Health, said.

"We know that early child development has profound influences on health and wellbeing across the life course. It follows that disruptions to sleep, especially if they occur at key times in development, could have important lifelong impacts on health," she said.

Researchers analyzed data from over 10,000 children participating in the UK Millennium Cohort Study, they looked at information on the participants'  bedtimes at two years, five years, and seven years. They also looked at reports from teachers on the children's' behavior. 

The team found a  "clinical and statistically significant link between bedtimes and behavior." The researchers believe interrupting circadian rhythms can lead to sleep deprivation and negatively effect the developing brain.

Children with irregular bedtimes were more likely to have "hyperactivity, conduct problems, problems with peers and emotional difficulties," which would get worse over time. When the children switched to a more scheduled bedtime their behavior showed significant improvements. 

"What we've shown is that these effects build up incrementally over childhood, so that children who always had irregular bedtimes were worse off than those children who did have a regular bedtime at one or two of the ages when they were surveyed," Kelly said. "For example, children who change from not having to having regular bedtimes show improvements in their behavior."

One in five of the study subjects under the age of three were given an irregular bedtime, by the time they were seven over half of the children went to bed between 7:30 and 8:30 p.m. Most kids who went to bed after 9:00 p.m. came from "socially disadvantaged backgrounds," and the effects of this were taken into consideration during the study.

"As it appears the effects of inconsistent bedtimes are reversible, one way to try and prevent this would be for health care providers to check for sleep disruptions as part of routine health care visits. Given the importance of early childhood development on subsequent health, there may be knock-on effects across the life course. Therefore, there are clear opportunities for interventions aimed at supporting family routines that could have important lifelong impacts," Kelly said.