Now that school is back in full swing, parents should be tapering off unnecessary screen time to assure kids don’t bypass physical activity and sleep.

“There is evidence from various types of studies that sedentary activity can and should be reduced. When possible, all screen-based activities should be reduced to mitigate risks,” said an American Heart Association Scientific Statement on youth sedentary behavior that was released in September.

Too much screen time has been tied to poor sleep quality and poorer reading and social skills.

Also, smartphones, tablets, TVs and other screen-based devices are making kids more sedentary – and sedentary behavior is tied to overweight and obesity in young people, according to the statement.

“There’s no question that screens are consuming more and more of kids’ time and attention,” said Tracie A. Barnett, an expert on pediatric obesity and sedentary behavior at Université du Québec in Montreal and chair of the committee that wrote the statement.

A 2014 study showed that teenagers who spent more time watching TV, playing video games or on a computer were more likely as young adults to be obese and have metabolic syndrome – a cluster of conditions that increase the risk for heart disease and stroke.

There has been no concrete connection between sedentary behavior among kids and other cardiovascular risk factors such as high blood pressure or high cholesterol. But what is concrete is that sedentary behaviors contribute to obesity among American children.

Obesity rates among 2- to 19-year-olds have risen from 10 percent in the late 1980s and early 1990s to 18.5 percent in 2016, according to federal data.

Five- to 8-year-olds are spending almost three hours a day watching TV and using smartphones, tablets or other devices, according to a recent analysis from the nonprofit Common Sense Media. A 2017 Nielsen survey of more than 4,000 parents showed about one in five 10-year-olds has their own smartphone.

So as usage increases, the name of the game is prevention – and parent’s play a key role in modeling healthy habits for their children, said Dr. Goutham Rao, a co-author of the AHA report and chair of the Department of Family Medicine at University Hospitals Cleveland Medical Center.

Keeping children off their cherished devices is no easy task, but parents must have rules and enforce limits, Rao said.

“Kids will find something to do if you say ‘no TV.’ Most of the time, whatever [the other activity] is, is going to me much healthier than watching TV,” he said.

The American Academy of Pediatrics recommends children ages 2 to 5 be limited to one hour of screen time a day, with consistent limits for older children on the amount of time and place they get to have screen time.

Rao and Barnett, parents themselves, suggest moms and dads involve children in coming up with screen time rules the family can stick to.

They both strongly recommend keeping smartphones, tablets and TVs out of bedrooms. And no electronics at the dinner table.

Instead, the idea is to find other things to do as a family – cook a meal together, play a board game or take a walk around the neighborhood.