Researchers at University College London say that irregular bedtimes can disrupt natural body rhythms and undermine brain maturation and the ability to regulate certain behaviors. The study, published in the journal Pediatrics, said the effect was not unlike jet lag in adults.
The study, involving more than 10,000 children, collected bedtime data at three, five and seven years, as well as incorporating reports from the children's mothers and teachers on behavioral problems.
The researchers say they found a significant link between bedtimes and behavior. Specifically, irregular bedtimes affected children's behavior by disrupting circadian rhythms, leading to sleep deprivation that affects the developing brain.
"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," said researcher Yvonne Kelly.
The study found that irregular bedtimes were most common at the age of three, when around one in five children went to bed at varying times. However, by the age of seven, more than half the children went to bed regularly between 7.30 and 8.30 pm.
As the children progressed through early childhood without a regular bedtime, their behavioral scores - which included hyperactivity, conduct problems, problems with peers and emotional difficulties - worsened. However, the researchers say that children who switched to a more regular bedtime had clear improvements in their behavior.
"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. But our findings suggest the effects are reversible," said Kelly. "For example, children who change from not having to having regular bedtimes show improvements in their behavior."
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Source: University College London