Irregular bed-times can cause problems for children

Late or irregular bed-times for children can induce symptoms similar to jet lag as well as behavioural problems and slower development, a British survey has found.

Some 10,000 children born between September 2000 and January 2002 were checked by researchers from University College London (UCL) at ages three, five and seven.

Children with late, or irregular bed-times displayed more hyperactivity and conduct problems and problems with peers as well as emotional difficulties the older they got. The results are particularly striking because the research team deliberately excluded from their study all children who were known to have ADHD, autism or Asperger syndrome.

“Disruptions to sleep, especially if they occur at key times in development, could have important lifelong impacts on health,” said Yvonne Kelly of UCL’s Epidemiology & Public Health department.

In the study one-tenth of seven-year-olds were in bed before 7.30pm; a quarter between then and 8pm; a third between 8pm and 8.30pm, one in seven between 8.30pm and 9pm, while 9 per cent were in bed after 9pm.

Children who switched to a more regular bed-time had clear improvements in their behaviour, according to the research published today in the medical journal Paediatrics.

Researchers believe that the lack of a regular bed-time disrupts the body’s circadian rhythms, while sleep deprivation slows brain development. “Not having fixed bed-times, 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,” Prof Kelly said.

Children with late or irregular bed-times are more likely to come from poorer homes, to skip breakfast, and to have a TV in their bedrooms, the researchers found.

However, habits can be changed: “Our findings suggest the effects are reversible. For example, children who change from not having to having regular bedtimes show improvements.”

However, the UCL researchers acknowledged the difficulties faced by parents: “Routines can be difficult to maintain when [both] are working long, and potentially unsociable hours.”