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Sleep — or lack of it — is common concern for parents. As new parents quickly learn, the well-being of everyone in the household can depend on how well their baby sleeps. And when they’re older, kids who don’t get enough sleep can have trouble paying attention, mood swings, behavior problems, and learning problems.

What Happens During Sleep?

As we sleep, our brains move between two types of sleep — non-REM and REM (rapid eye movement) sleep. Together, the stages of non-REM sleep and REM sleep make up a sleep cycle. Babies spend more time in REM sleep and their sleep cycles are shorter than adults. Time spent in REM sleep decreases and sleep cycles get longer as kids get older. By the time kids start school, one complete sleep cycle lasts about 90 minutes, which is similar to an adult's.

Stage 1 and stage 2 non-REM sleep are light sleep stages:

  • A person can wake up easily.
  • Eye movements slow down, heart and breathing rates slow down, and body temperature decreases.

Stage 3 non-REM sleep is deep sleep:

  • It's harder to wake someone up. When awakened, a person often will feel groggy and confused.
  • Night terrors, sleepwalking, and bed-wetting can happen during this stage.
  • This is the most refreshing sleep stage. It’s during this stage that the body releases hormones needed for growth and development.

In the final, REM stage of the sleep cycle:

  • The eyes move quickly under the eyelids, breathing gets faster, and the heart beats faster. You can’t move your arms or legs during REM sleep.
  • This is when we have our most vivid dreams.
  • REM sleep is important for learning and memory. 

How Much Sleep Do Kids Need?

How much sleep kids need varies by age. While every child is different, experts recommend:

  • infants (0–3 months): 14–17 hours, including naps
  • infants (4–12 months: 12–16 hours, including naps
  • toddlers (1–2 years): 11–14 hours, including naps
  • preschool (3–5 years): 10–13 hours, including naps
  • school-age (6–13 years): 9–12 hours
  • teens (14–17 years): 8–10 hours

How Can I Tell if My Child Isn’t Getting Enough Sleep?

A child who isn’t getting enough sleep may:

  • fall asleep during the day
  • be hyperactive (especially younger children)
  • have trouble paying attention
  • struggle with school work  
  • be cranky, whiny, irritable, or moody
  • have behavior problems

What Can Help Kids Sleep?

For kids of all ages, set up a bedtime routine that encourages good sleep habits. These tips can help kids ease into a good night's sleep:

  • Stick to a regular bedtime. You can give your kids a heads-up 30 minutes and then 10 minutes beforehand.
  • Encourage older kids and teens to set a bedtime that allows for the full hours of sleep needed at their age. A bedtime routine could include washing up and brushing teeth, reading a book, or listening to quiet music.
  • Turn off all screens (TV, computers, phones, tablets, and video games) at least 1 hour before bedtime. Consider removing all devices from your child’s bedroom.

More About Sleep by Age

Learn more about sleep as your child grows:

Medically reviewed by: Mary L. Gavin, MD
Date reviewed: January 2021