Later preschool bedtimes could lead to weight gain later on

What time your preschooler goes to bed might affect the child’s weight later on, a new study suggests.

Researchers at the Karolinska Institute in Stockholm, Sweden, based their findings on 107 children who took part in an obesity prevention project. Sixty-four of those 107 kids had parents who were overweight or obese, putting the children at higher risk.

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The kids’ sleep habits were monitored for one week each year from age 2 to age 6 using a wrist device that kept track of the child’s activity. All of the children were basically the same size at the beginning of the study, which was published Tuesday, February 18, in the journal Pediatrics.

The study found that, on average, kids who routinely went to bed after 9 p.m. had greater gains in body mass index and waist size over the years.

The findings do not prove that later bedtimes cause excess weight gain, Dr. Nicole Glaser wrote in a commentary accompanying the study.

Dr. Claude Marcus, a professor of pediatrics at the Karolinska and senior researcher on the study, agreed. "The causality is difficult to establish," he said.

It could be that kids who stay up later are eating during those hours, Marcus said, or their parents put fewer limits on them.

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The link between bedtime and weight gain "was independent of total time asleep, and it remained even after the researchers accounted for factors like kids' exercise habits and 'screen time,' and parents' education levels," according to Medical Xpress.

Even though this study doesn’t prove cause and effect, Glaser said an early bedtime “is absolutely a good idea," and not just for kids.

"Parents can have some much needed quiet time and time together to recharge the batteries, so they can have more energy for their kids the next day," she said.

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