Summer brings inevitable inconsistency in bedtime routines, but new research shows that once school starts, maximizing your preschooler’s sleep can make a big difference in how well they transition to kindergarten—and their subsequent school performance. 

In a study published in The American Academy of Pediatrics (AAP)’s journal "Pediatrics," researchers tracked the sleep patterns of 221 soon-to-be kindergartners with an eye toward how much sleep they got in a 24-hour period, and whether that sleep was consolidated overnight or combined from naps and nighttime sleep. 

They found that the kids who consistently slept for at least 10 hours at night—not including naps—were better able to adjust to kindergarten, and their teachers reported they had better socio-emotional, learning engagement and academic outcomes than those kids who had more irregular sleep patterns.

Related: Our son thanked us for ‘redshirting’ him in kindergarten

In the study, the teachers were blind to how much sleep each child was getting, and the researchers controlled for income-to-poverty threshold ratios, child health status and number of missed school days. 

“The transition to kindergarten requires new social, emotional, and cognitive competencies, significant expansion of children’s social networks, and formal instruction and evaluation never experienced before,” write the study authors. They noticed that while factors like children’s health and their socioeconomic status have been examined in terms of kindergarten transition success, sleep duration has not. 

Why sleep is so important

As a society, we tend to overlook the value of sleep—but according to sleep expert and neuroscientist Dr. Matthew Walker, it’s incredibly important for brain health. “Sleep is the single most effective thing we can do to reset our brain and body health each day,” he writes in his book Why We Sleep: Unlocking the Power of Sleep and Dreams. “When sleep is abundant, minds flourish. When it is deficient, they don't.”

In kids, sleep can improve focus and concentration, as well as memory, mood, immune function, school performance and behavior, notes AAP

Related: California becomes first state to delay school start times—here's why that matters

The American Academy of Sleep Medicine and National Sleep Foundation recommend 5-year-olds get 10 to 13 hours of sleep in a 24-hour period, but the Pediatrics study shows that at least 10 hours of consolidated nighttime sleep seems to be the magic number in terms of kindergarten success. 

Focus on bedtime consistency

The more regularly a child slept for at least 10 hours at night, the better the child was able to adjust to kindergarten, note the authors. Their kindergarten success was even more pronounced if the 10 hours of nightly sleep was established before kindergarten began, when the child was still in preschool. 

"The more consistently children got 10+ hours of sleep during the night, the better the children's peer relationships, relationships with their teachers, overall academic performance, and sight recognition of words and letters," says lead study author Douglas Teti, distinguished professor and head of the department of human development and family studies at The Pennsylvania State University, to CNN.

Related: Why I got strict about a 7 p.m. bedtime for my kids

Start now for long-term sleep success

You may want to start sooner than later if your little one is starting kindergarten in the fall, given that it was long-term sleep habits that seemed to make the most impact.

"The intervention should begin before kindergarten begins in September," Teti says. "Parents should do what they can to help their children get most if not all of their sleep on a regular basis during the children's nighttime sleep period." 

That may mean cutting back on naps to help consolidate your child's sleep at night. Naps may still be developmentally appropriate for your kiddo, but if it means their bedtime is pushed back till later, it could be worth omitting the nap. If you have questions or concerns, your child's pediatrician is a good resource.

Healthy sleep habits for young kids:

  • For early school-age kids, the authors recommend bedtime before 9 p.m., which would make wake-up time around 7 a.m., for a full 10 hours of nighttime sleep. Naps should count as extra, not toward that 10-hour goal.
  • Kids should avoid all screens like TVs, tablets and phones at least 30 minutes before bedtime.
  • Parents and caregivers should be involved in their child’s bedtime routines, keeping them as consistent as possible night after night. That may look like a bath after dinner, followed by books before tucking in. 
  • Because parents’ and kids’ sleep schedules tend to be closely aligned, parental sleep habits are also important to monitor, note the authors. That may mean starting a more consistent bedtime routine for yourself, too. 

“Good sleep hygiene [e.g., organized bedtime routines, limited screen access, and bedtimes before 9 p.m.] may be as critical for the well-being of children as it is for adults,” note the authors.