Many children aren’t getting the sleep they need. Lack of sleep has been associated with poor school performance, inattention and hyperactivity, depression, irritability, and now — even obesity.

In a study published in the scientific journal Sleep, researchers examined sleep and body mass index (BMI) in twins. They found that sleeping more than nine hours a night may actually suppress the influence that genetics can have on body weight.

What are the genetic factors that influence body weight? Experts say previous research indicates that glucose metabolism, energy use, fatty acid storage and satiety affect individual BMI.

The twins who slept fewer than seven hours a night measured increased BMI and greater genetic influences on BMI. Researchers concluded that the results suggest that shorter sleep allows for expression from the obesity related genes.

It is also possible that extended sleep protects the body by suppressing the expression of obesity genes.

These results may suggest that behavioral weight loss measures would be most effective if an individual pays careful attention to getting a good night’s sleep on a regular basis.

Sleep is when all the cells in the body recharge and get ready for the next day, says pediatrician Ron Fischler, MD, a member of the Arizona Chapter of the American Academy of Pediatrics (AzAAP) and past chapter president.

How much sleep should a child be getting? While there is some variation in how much sleep each individual needs, Fischler says

• Children in the first year need 15 hours per night
• One to three year olds need 12 hours per night plus a one hour nap
• By school age, most children need 10-12 hours per night
• When they reach adolescence, they need 8-9 hours per night

Why don’t kids get enough sleep? Some kids lead over-scheduled lives, with too many activities and too much homework. Others stay on social media sites, text or play video games late into the evening. For others, falling asleep in front of a TV shaves off precious sleep time.

Fischler says there are several reasons that some children have difficulty relaxing for sleep. Worries about school work or friends can keep them up at night. Staying up late on the weekends can prevent their biological clocks from resetting for the school week, causing them to wake up feeling groggy and unable to function well in class.

Some children have sleep apnea, a condition that causes snoring and obstructed breathing. That can mean frequent night awakenings and non-restful sleep.

What can parents do to encourage kids to get the sleep they need? Here’s Fischler’s checklist:

• Understand how much sleep the average child needs based on their age. Then figure out what time they need to get to bed to get up and still get enough sleep for their age
• Help your child pick a reasonable amount of activities balanced against academic load
• Limit highly active sports in the evening. It is hard to unwind from the excitement of vigorous exercise and competition
• Limit access to computer and smart phones after bedtime.
• Discourage TVs in a child’s bedroom

If your child has loud snoring, poor school performance or behavioral issues, or problems getting to sleep, says Fischler, schedule an appointment with your pediatrician.

What goes on during a sleep study? Watch as Michael Eichenberg, RPSGT, Manager, Banner Desert Sleep Center talks about sleep disorders and sleep studies for children:

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