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Experts say turning off electronic equipment at bedtime is one of the ways parents can set up a 30-minute bedtime routine for children. Getty Images
  • Researchers say children who stay up late may have a higher risk of obesity.
  • A shorter sleep duration can affect a child’s body in numerous ways, including an increase in insulin levels.
  • Experts recommend that parents set a 30-minute bedtime routine that includes turning off electronics, a warm bath, and a bedroom story.

Parents have another reason to put their kids to bed early.

Staying awake past 9 p.m. may increase the risk of obesity in children 2 to 6 years old.

So says a study published today in Pediatrics: Official Journal of the American Academy of Pediatrics.

Researchers recorded sleep activity in participants from the Early Stockholm Obesity Prevention Program using a wrist-worn actigraphy device.

They found that young children who frequently stayed up until 9 p.m. or later had greater increases in both body mass index (BMI) and waist circumference, particularly in children of overweight or obese parents.

“The take-home message is that the way we live — and not only our eating habits and physical activity — will affect the children’s risk for an unhealthy weight gain,” Dr. Claude Marcus, a study author and professor of pediatrics at Karolinska Institutet in Sweden, told Healthline.

The American Heart Association reports that 1 in 3 teens in the United States are overweight and are at greater risk for diseases previously not seen until adulthood, such as type 2 diabetes, high blood pressure, and elevated blood cholesterol levels.

“Since obesity is associated with multiple other cardiovascular risk factors, like increased blood pressure, lipids, and glucose, obesity prevention is an important target for children,” Donna Arnett, PhD, a professor of cardiovascular health at the University of Kentucky and an American Heart Association medical expert, told Healthline.

Childhood obesity is also related to psychological symptoms such as depression and anxiety, low self-esteem and lower self-reported quality of life, and social issues such as bullying and stigma, according to the Centers for Disease Control and Prevention (CDC).

The relationship between sleep and weight is complex.

“The causality is difficult to establish,” said Marcus. “We don’t think it will affect a child negatively to have some days with irregular bedtimes. It is when the irregularity is standard it might cause problems.”

Dr. Shalini Paruthi, co-director of the Sleep Medicine and Research Center at St. Luke’s Hospital in St. Louis and a spokesperson for the American Academy of Sleep Medicine, said previous studies have shown associations between improper sleep and weight gain in children.

“We know that short sleep duration in children is associated with higher insulin levels and also a higher insulin insensitivity, meaning young bodies may not be able to process insulin and glucose properly, which can lead to weight gain,” she told Healthline.

“Additionally, studies show that lack of sleep increases the desire for food, and the fatigue from lack of sleep decreases physical activity,” Paruthi added.

“Studies also show that when children do not sleep enough, their leptin and ghrelin hormones can be affected.”

She explained that leptin is secreted in fat cells and helps the brain signal when to slow down eating.

Ghrelin, secreted in the stomach, stimulates hunger.

“Research is ongoing to help explain these theories in more detail,” Paruthi said.

Dr. Carol Rosen, a professor of pediatrics and the medical director of pediatric sleep services at Case Western Reserve University School of Medicine and medical director of pediatric sleep services at University Hospitals Rainbow Babies & Children’s Hospital in Ohio, said there are still some unanswered questions.

“A number of studies have shown that short sleep duration is associated with the development of obesity in children, but there are several kinds of limitations of those existing studies,” Rosen told Healthline.

“Some of those studies have depended on parent reports of sleep and wake times, which can be unreliable, rather than an actual objective measurement of sleep times,” she added.

“In addition, what was the exact nature of the sleep patterns [in those previous studies]?” said Rosen.

“Did the kids just not get enough sleep, did they just go to bed too late, did they wake up a lot at night, or just have a very irregular schedule?”

Additionally, she said, “Are there other family or social factors that contribute to an increased risk of obesity?

“Finally, are children of parents who are overweight or obese more likely at great risk for developing obesity compared with children whose parents have a normal weight?”

Rosen noted the wrist-worn actigraphy in this study adds objectivity.

“By looking more deeply at all those kinds of questions, that’s where this study provides important new findings,” Rosen told Healthline.

Experts agree that following a bedtime routine is the best way to get children to develop healthy sleep hygiene habits.

“While the causes for the weight gain with shorter sleep duration or late sleep are unclear, the consistency of this finding in children with prior observations in adults suggests that parents ensure their children have a regular and early bedtime,” said Arnett.

Rosen agrees.

“Once a parent knows those minimum amounts of sleep (a parent may be aware that their individual child may need even more sleep than the minimum to be at their best) and knows the time their child needs to be up in the morning for school or other family activities, then the parent can select an appropriate goal bedtime/falling asleep time,” she said.

Rosen recommends the parent and child plan a short bedtime routine about 30 minutes or so before that desired bedtime.

Paruthi says an example of a bedtime routine may include:

  • shutting off all electronic devices 1 hour before bedtime
  • taking a warm bath and brushing teeth
  • reading a book or singing a song
  • turning the lights out at bedtime

Understand that some schedule variation is expected.

“Sometimes extracurricular activities will disrupt the usual bedtime,” said Paruthi.

“However, it is still important to go through the activities of the bedtime routine, just a little faster or with shorter times allocated to the activities. For example, instead of 10 minutes of reading time, there is now 5 minutes of reading time.”

Rosen has a few other suggestions.

“Ideally, the bedtime routine also excludes ‘alerting’ bedroom/bedtime electronics, for example, TV, cellphone, texting, tablet, or video game time,” she said.

And while daytime physical activity is recommended, Rosen said, “Vigorous physical activity immediately before bed should be avoided.”

She also noted it’s best to avoid drinking caffeinated beverages later in the day.

If you’re uncertain about an appropriate bedtime for your children, Paruthi suggests using the online calculator provided by the American Academy of Sleep Medicine.