By September, Arizona children and teens have had several weeks to adjust to the demands of a new school year. Classrooms, teachers, homework, sports and extracurricular activities are no longer quite so “new,” and most families have established their regular weekday routines.

That makes now an important time to look at how children are sleeping.

If a child is still struggling to get out of bed, having trouble focusing at school, falling asleep in the afternoon or experiencing changes in mood or behavior, lack of sleep may be playing a role.

Sleep and School Success

Sleep is essential at every age, but it is particularly important during childhood and adolescence when the brain and body are still developing.

While children sleep, the brain processes and stores information learned throughout the day. Sleep also supports attention, memory and problem-solving, all of which are important in the classroom.

However, the benefits go well beyond academics. Adequate sleep supports physical growth, immune function, metabolism and emotional regulation. When children do not get enough, managing frustration and stress may become more difficult.

The challenge: in youth, sleep deprivation can show up in unexpected ways.

Signs by Age

In younger children, insufficient sleep can sometimes look like the opposite of exhaustion. Hyperactivity, impulsivity, irritability, emotional outbursts and difficulty following directions may all be signs that a child needs more rest.

Elementary and middle school students may have trouble concentrating, remembering information or completing assignments. Tasks that were once manageable may suddenly become frustrating, and mornings may become increasingly difficult.

Teens may struggle to wake up, fall asleep after school, have difficulty concentrating or experience lower motivation and changes in mood.

Adolescence presents an additional challenge because the body’s internal clock naturally shifts later during the teen years. Many teens do not feel sleepy until later at night, even though they still need significant sleep. Early school mornings combined with homework, athletics, jobs and social activities can quickly cut into those hours.

How Much Is Enough?

Another challenge for parents is that sleep needs change as children grow.

After the first few months of life, infants generally need 12 to 16 hours during a 24-hour period, including naps. Toddlers typically need 11 to 14 hours, while preschoolers need about 10 to 13 hours.

School-age children, ages 6 to 12, should generally get nine to 12 hours each night.

Teenagers need eight to 10 hours.

Even consistently missing 30 to 60 minutes can add up over the course of a school week, especially when wake-up times remain early.

Finding the Missing Hours

When a child is not getting enough sleep, the entire daily schedule is worth examining.

Working backward from the required morning wake-up time can help families determine what time kids need to go to bed in order to get enough sleep. Homework, evening practices, extracurricular activities and caffeine later in the day may all contribute to later nights.

Screens are another common factor.

Phones, tablets, televisions and gaming devices can delay the body’s natural production of melatonin, which helps signal that it is time to sleep. Just as importantly, texting, gaming, videos and social media keep the brain engaged when it should be winding down. Notifications can even interrupt sleep during the night.

A consistent, screen-free bedtime routine can help. For younger children, that might include a bath and book. Older children and teens may benefit from reading, stretching, quiet music or another calming activity before bed.

When More Sleep Is Not Enough

Sometimes the number of hours is not the problem, or perhaps not the only problem.

A child may spend enough time in bed but still experience poor quality or disrupted sleep. Loud snoring, pauses in breathing, choking or gasping during sleep, frequent nighttime awakenings and excessive daytime sleepiness may signal an underlying sleep issue.

By this point in the school year, families have had time to establish routines and see patterns in how children are functioning each day. If school-day challenges such as difficulty concentrating, changes in mood or behavior, or persistent daytime sleepiness continue well beyond those first few weeks, it’s time to take a closer look at sleep. A conversation with your pediatrician can help determine whether an underlying sleep issue could be contributing.

Rupali Drewek, MD, is a pediatric pulmonology and sleep medicine specialist and co-medical director of the Sleep Disorders Program at Phoenix Children's. For more information, visit www.phoenixchildrens.org