If you’re looking to help your child function at peak level, it’s time to pry the iPad from their hands and encourage them to get moving and hit the pillow early.

That’s according to a new study funded by the National Institutes of Health, which found that kids who engage in at least 60 minutes of physical activity a day and get 9 to 11 hours of sleep at night scored significantly higher on tests measuring mental ability.

The other ingredient to this recipe for success: no more than 2 hours of screen time a day.

“These findings highlight the importance of limiting recreational screen time and encouraging healthy sleep to improve cognition in children,” researchers wrote.

The study included 4,524 children between the ages of 8 and 11 from across the United States. The kids took a series of 6 tests designed to measure language skills, memory, planning ability and speed at completing mental tasks.

Researchers found that the 5% of children who met all three criteria scored 4% higher on the assessments than the nearly 30% who failed to meet any.

Kids who reported at least 9 hours of sleep and less than 2 hours in front of a screen daily saw a more than 5% increase in scores than those who didn’t meet those numbers.

“It may be that screen time is affecting sleep,” lead author, Jeremy J. Walsh told the New York Times. “Sleep is critical behavior for shaping our brains. Kids need to be sleeping nine to 11 hours a night for their cognitive development to be optimal.”

According to the National Institutes of Health, adolescents and school-aged children in the U.S. spend an average of 7 hours a day in front of a screen.  A 2011 study revealed about 60% of adolescents report getting less than 8 hours of sleep on school nights.

“With the ubiquitous presence of media items in an adolescent’s bedroom, screen time is hypothesized to be a cause of insufficient and low quality sleep,” researchers wrote.

They pointed to three ways in which screens can disrupt quality sleep.  First, kids get so sucked into their devices that they waste time that could be spent sleeping. Second, youth are easily stimulated by the content they consume online – whether through television, social media or video games – and that stimulation can make it much harder to fall asleep. Finally, researchers explained that light from a screen can have a significant impact on alertness and circadian rhythm – suppressing the production of melatonin, a hormone that helps you sleep.

Common Sense Media offers the following tips to help you help your child get a good night’s sleep.

Guidelines for a better night’s sleep:

  1. Encourage physical activity instead of screen time after school
  2. Keep devices off the bed
  3. Try white-noise apps to calm babies and toddlers
  4. Limit young kids’ exposure to violent content
  5. Keep TVs out of the bedroom
  6. Make the bedroom a “no-connection” zone
  7. Minimize screen time right before bed
  8. Introduce your kids to meditation or calming apps
  9. Set up a phone/iPod charging station in the family living room
  10. Model healthy sleep habits