“The body starts making melatonin in the evening hours to help us feel sleepy, fall asleep and stay asleep,” he said. “Elementary school-aged children produce it earlier so it’s easier for them to go to bed earlier. And young children just need more sleep in general.”

But when children get into middle and high school, their bodies start to make melatonin later in the evening, even though they still need eight to 10 hours of sleep, he said.

Starting the day

So even a teenager who follows all the classic sleep rules, such as coming right home from school, doing homework early and having a good wind-down period, may still have a hard time falling asleep before 10 or 11 p.m. because of their melatonin levels, said Hintze, who is with the division of pediatric sleep medicine at Greenville Health System.

“If you have to be at school at 7 or 7:30, and you have to get up an hour before that to get ready and have breakfast and catch the bus or whatever, and you’re getting up at 6 or 6:30, the math doesn’t add up,” he said. “And you end up chronically sleep deprived.”

Having a regular sleep schedule could be the secret for better grades.(Photo: iStock/Getty Images)

That is less of a problem in a district like Greenville County, where elementary school starts at 8 a.m., middle school starts at 8:30 a.m. and high school starts at 8:45 a.m., he said, because teens can still fall asleep at 10 or 11 p.m. and get eight hours. But private schools tend to have an earlier start, he said.

Getting enough sleep

And chronic sleep deprivation can result in poorer school performance, more tardiness, impaired driving and increased risk for mental health problems such as depression, he said.

“If you increase sleep from seven to nine hours a night,” he said, “the risk of car accidents goes down by 16.5 percent.”

Both the American Academy of Pediatrics and the American Academy of Sleep Medicine advocate a school start time of 8:30 a.m. or later so children get enough sleep, he said.

Children 6 to 12 years old need nine to 12 hours of sleep a night, he said. Teens need eight to 10 hours.

Establish a pattern

So how do you do it?

The most important thing, Hintze said, is to establish a sleep pattern.

“Oftentimes during summer, we get lax with the rules around sleep. With some kids, it’s just all over the place. They’re taking three-hour naps in the middle of the day and going to bed at 3 a.m.,” he said.

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Dr. Jonathan Hintze(Photo: Greenville Health System)

“Have some schedule where there’s no napping, they’re awake all day,” he added, “and they’re going to bed around the same time and waking up around the same time.”

If the child has to wake up at 7 a.m. to get to school on time and they’ve been getting up at 9:30 a.m. during the summer, he said, focus on shifting the time they wake up.

Early to bed

“If you wake up earlier,” he said, “you will want to go to bed earlier.”

So start by waking your child half an hour earlier for three days and then increase it by half an hour for another three days and so on, he said.

Ideally, he said, this should start a week or so before school starts. If you wait until the first day of school, the child will be in a haze the first week as they adjust, he said.

Waking up earlier can mean going to bed earlier.(Photo: getty images)

Keeping that pattern on the weekends is important, too, Hintze said, or Monday mornings will be a hassle every week.

“If you wake up at one time during the week and another time on the weekend, it’s the equivalent of traveling to a different time zone every weekend,” he said. “If you are somebody who has to get up at 6:30, I wouldn’t sleep later than 7:30, or more than one time zone out of where you are.”

Cool and dark

A good sleep environment is also critical to getting enough sleep, Hintze said.

The room should be cool, between 65 and 70 degrees, he said, and it should be dark, with a night light if needed, but no other lights.

Light is actually the biggest influence on circadian rhythm, or the body’s internal clock, from a sleep standpoint, he said.

So getting as much sunlight in the morning and limiting artificial light exposure at night will help with sleep, he said. For those who have a hard time waking up in the morning, a light box that signals the body to suppress melatonin production may help.

Restricting screen time

The room should also be quiet, although a noise machine that plays rain without a lot of sound variability, for instance, or a fan can help with sleep, Hintze said.

And children should not use electronics, including TV, iPod, phones, video games or tablets, at least 2 hours before bedtime, he said.

Restrict your child's screen time at least two hours before bed.(Photo: Photo by Nick White)

“The biggest thing ... is getting the TV and electronics out of their room,” he said, adding that TV watching should be restricted to the living room or den.

“And they don’t need to be on social media checking Facebook or Instagram,” he added. “That will lead to hours lost flipping pages when they could have been sleeping.”

To combat that, put the phone on the charger in the parent’s room at a set hour, he said. Otherwise, it's too tempting, he said.

No more bedtime battles

While exercise in general is good for sleep, it’s usually best done before or after school because sleep comes easier after a wind-down period of a couple of hours, Hintze said.

It's also advisable to limit eating before bedtime, he said.

“You don’t want to lay down with a full stomach,” he said. “Having a reasonable dinner time, say 6 or 7 p.m., or earlier for younger kids, is helpful.”

For those who wake up hungry during the night, a light snack like something with peanut butter about half an hour before bed could help, he said.

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William, Joshua and Sean Reynolds pose for a portrait in their bedroom on Thursday, Aug. 16, 2018. (Photo: JOSH MORGAN/Staff)

Adjustment time

Over the summer, Reynolds said, Sean, William and Joshua, now 9, 7 and 4, often stayed up until 10 p.m.

But she and her husband, Wendell, have started working on earlier bedtimes as the school year approaches.

“We were at the beach last week and tried to make a clean break from that,” she said. “During the school year, we try to have them in bed at 8:45 and lights out at 9. And right now, we’re within 15 minutes of our target bedtimes.

“And they’ve been going to summer camp this week and getting up fairly close to morning wake-up time,” she added. “But it usually takes us a week or two to be adjusted.”

This is a part of an ongoing series of stories leading up to the first day of classes, which for most schools in the area is next week. Follow online at GreenvilleNews.com on Monday, Aug. 20, for coverage of the first day.