Back to Sleep

How much is really enough?
Black female teenage student sleeping at school

For parents and kids alike, the transition to earlier bedtimes and wake-up times can be one of the hardest parts of going back to school.

That’s totally normal, according to Sigfus Gunnlaugsson, MD, a pediatric pulmonologist and sleep medicine physician at The University of Vermont Medical Center.

“Our natural environment and our social cues are different during the summer,” Dr. Gunnlaugsson says. “It’s light out later, and social events tend to run later into the evening. It’s completely normal for the typical evening routine to go away.”

We have our normal circadian rhythms working against us, too, he says, something that can be particularly noticeable in teenagers.

“Most adults have a normal circadian rhythm that’s longer than 24 hours, meaning that our bodies like going to bed later and waking up later,” he says. As adolescents transition from child to adult, they tend to become night owls, a normal developmental phenomenon, regardless of the time of year.

It all comes to a head in the fall, when our social schedules suddenly don’t match up with our biological ones. 

The Impact of Poor Sleep

It’s common sense that when we don’t get enough sleep, our performance suffers. Research backs it up: According to a 2022 NIH study of school-age children, altered sleep habits have a major effect on academic performance.

“Sleep provides a period of recalibration after the day,” Dr. Gunnlaugsson explains. “During sleep, our brains process the day’s experiences, the information we’ve learned and the social-emotional learning we’ve done. Especially for kids, a whole lot of development is going on during sleep.”

The short-term effects of poor sleep may show up in behavior problems. Children may be more hyperactive, aggressive, irritable or moody. “Kids typically don’t slow down and take a rest when they’re tired, they tend to increase their motor activity,” Dr. Gunnlaugsson explains.

Longer-term, poor sleep is also associated with a lot of physical and mental health problems. In both kids and adults, sleep deficiency is linked to heart disease, high blood pressure, diabetes, stroke, obesity and depression and anxiety.

So, while later summertime bedtimes may be normal, it’s important for families to roll back the bedtime clock once school starts so kids get the sleep they need. 

How Much Sleep Is Enough?

Preschool-age children should get 10 to 13 hours of sleep, including daytime naps. Children ages 6 to 12 should get about 9 to 12 hours, adolescents and teenagers should get about 8 to 10 hours, and adults should aim for 7 to 9 hours.

The ideal amount of sleep is a range, not an exact number, he says. “Sufficient sleep for you as an individual is the amount of sleep that allows you to function up to your potential and fully participate in your school, work and social life,” he says. “Two siblings, or two children the same age, may have vastly different sleep needs.”

He also suggests that parents take note of how long their children tended to sleep during the summer, when they were waking up based on their body, not their alarm clock. “Even if the whole schedule was shifted an hour or two later, when they wake up naturally, they’re telling you how much sleep they need,” he says.

Quality vs. Quantity

The number of hours in bed isn’t the only consideration for adequate sleep, Dr. Gunnlaugsson points out. Sleep quality is also important.

Every family can take some simple “sleep hygiene” steps to ensure they’re sending their children off to bed under the best possible conditions. These include having a 10-to-15-minute relaxing routine just before bedtime. “Whether that’s reading, chatting about the day, or maybe having a bath – those provide signals to the body that nighttime is coming,” he says. He also suggests limiting screens 30 to 60 minutes before bedtime. And finally, he recommends keeping to the same sleep schedule seven days a week, even on days without early-morning commitments.

The key to making the transition back to school easier is to not do it all in one night, says Dr. Gunnlaugsson. The best approach is to gradually reset the clock, advancing bedtime and wake-up time by 15 minutes every night for the days leading up to day one.

If you’re not that regimented, the first couple of weeks can be a little rough. But it will pass as our bodies get used to the earlier hours.

With three children of his own, ages 8, 3, and 4 months, Dr. Gunnlaugsson is sympathetic.

“[After summer] we’re expected to flip into a rhythm that’s constrained by school start times, which can be 2, 3, even 5 hours earlier than our typical wake-up time during the summer months. It’s almost like you’re flipping time zones, and you feel like you’re being woken up in the middle of the night to go to school.”

When school starts, all of us – even the sleep specialist – have to hit the reset button.

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