How sleep affects development and behaviour

How sleep affects development and behaviour
Getting a good night’s sleep is important for your child’s learning and development. Not getting enough sleep can interfere with your child’s ability to learn.

Quality sleep promotes healthy childhood development and supports learning. Conversely, not getting enough sleep can affect children’s health, memory, logical reasoning, behaviour, and emotional regulation.

How much sleep do kids need?

The amount of sleep a child needs varies from one child to the next. There is no one-size-fits-all solution. That’s why sleep recommendations are given as ranges, rather than specific numbers.

The following table explains how many hours of sleep, on average, children should be getting, including naps:

Number of hours of sleep
1 to 2 years
11 to 14 hours
3 to 5 years
10 to 13 hours
6 to 12 years
9 to 12 hours

How to tell if your child is getting enough sleep

You know your child is getting enough sleep if they feel rested when they wake up and do not show signs of fatigue during the day, except before naps and at bedtime.

Here are some signs of a lack of sleep:

  • It’s difficult to wake your child in the morning.
  • They are in a bad mood when you wake them in the morning.
  • They yawn often.
  • They have poor concentration and are clumsier than usual.
  • They are irritable, grumpy, or cranky, and they burst into tears over the slightest thing.
  • They are more impulsive or more aggressive than usual.
  • They show no interest in things they usually like.
  • They become more talkative, noisy, and hyperactive.

The benefits of good sleep

Getting enough quality sleep is essential for physical and mental health. Quality sleep promotes healthy childhood development and supports learning. When they sleep, children consolidate what they have learned during the day.

Getting enough sleep therefore helps your child do the following:

  • Retain new language and motor skills, information, and problem-solving strategies
  • Make better use of their logical reasoning
  • Have better control over their emotions
  • Stay alert throughout the day
  • Focus better and for longer periods of time
  • Be more creative
  • Have more energy throughout the day
  • Establish and maintain good relationships with others
  • Develop well physically
  • Strengthen their immune system

Sleep basics

The body has a 24-hour internal clock that regulates its sleep-wake cycle. This internal process is called the circadian rhythm. It is influenced by various cues, such as light and dark. Before you can address your child’s sleep needs, it’s important to understand the basic breakdown of a good night’s sleep.
Nighttime sleep is divided into two phases:
  • Non rapid eye movement (non-REM) sleep, which includes periods of light and deep sleep. During non-REM sleep, and more particularly in the deep sleep stage, brain waves slow and gain amplitude.
  • Rapid eye movement (REM) sleep, which is when the brain dreams. REM sleep is also called paradoxical sleep because while you’re deeply asleep during this stage, your brain activity is similar to what is observed in the waking state.
Together, REM and non-REM stages of sleep form a full cycle that lasts around 40 minutes in babies 4 to 9 months old. Babies go through about a dozen cycles a night during their first year. As your child grows, their sleep cycles lengthen, eventually reaching 90 minutes. At this point, the cycle repeats 6 to 8 times a night, depending on the child’s age and how long they sleep.

How not getting enough sleep affects your child

A lack of sleep can interfere with several aspects of your child’s development. Here are some of the possible effects of sleep deprivation in children:

  • Difficulty managing their emotions, making them prone to mood swings, impulsiveness, aggression, and depression
  • Decreased mental agility
  • Increased hyperactivity
  • Difficulty staying alert and focused
  • Decreased motivation
  • Forgetfulness
  • Poorer eating habits and higher risk of weight gain
  • Greater tendency to fall sick

Making sure they get a good night’s sleep

There are several things that can affect your child’s sleep. If they have trouble falling asleep or wake up at night, it may be time to reassess certain lifestyle habits.

  • Sleep schedules
    Keep bedtime and morning wake-up times consistent, including on weekends if possible. This is especially important for children who have difficulty sleeping.
  • Bedtime routines
    To help get your child ready for sleep, create a routine you can do together every night before going to bed. Keep the routine short (about 15 minutes). Create a positive, relaxed environment to make the routine go smoothly. To learn more, read our fact sheet on sleep and the importance of a bedtime routine (link in French).
  • Physical activity
    Your child needs to move and burn off energy. With that in mind, reserve more stimulating activities, such as running, jumping, and climbing, for the daytime, and focus on quieter activities in the evening. Take them outside to play during the day as much as possible. Natural light helps kids regulate their sleep schedules.
  • Food and drinks
    In the evening, avoid giving your child energizing foods, such as anything with caffeine (e.g., chocolate, tea, and energy drinks). Furthermore, it’s is best to eat larger meals no more than one or two hours before bedtime, as digestion can disrupt sleep. On the other hand, an empty stomach can also prevent them from sleeping well. In the evenings, opt for a healthy snack.
  • Screens
    Limit the use of computers, mobile devices (tablets and phones), and TV before bedtime. Not only do screens overstimulate the brain before sleeping, but the bright light can wake us up, making it difficult to wind down. Children also shouldn’t have televisions, computers, or video game consoles in their rooms.
  • Homework
    The brain needs time to transition from intense activity to sleep. Make sure your child finishes their lessons and homework before dinner or in the early evening to leave room for some downtime before bed.
  • Sleeping environments
    Sleeping in a room that is too bright, too hot, or too noisy can cut sleep short and make falling asleep take longer. Keep your child’s bedroom as dark as possible, as complete darkness is best for sleep. Try to keep the noise level in the rest of the house as low as possible while they’re asleep.

When should you consult an expert?

Don’t hesitate to consult a health professional (e.g., a family doctor, nurse, pediatrician, or psychologist) in the following situations:

  • You have concerns about your child’s sleep.
  • Your child often seems tired during the day.
  • They are having difficulties in school and you think it may be due to a lack of sleep.
  • You believe that your child’s sleep difficulties are related to a physical health problem (e.g., sleep apnea, breathing or digestive issues) or psychological difficulties (e.g., anxiety).

To learn more about other sleep-related difficulties (fears, nightmares, night terrors, etc.), consult our sleep disturbances fact sheet (link in French).

To learn more about children’s sleep, read our feature, Understanding sleep better.

Things to keep in mind

  • Quality sleep is essential for physical and mental health. Getting a good night’s sleep is also important for your child’s learning and development.
  • You know your child is getting enough sleep if they wake up rested and do not show signs of fatigue during the day, except before naps and at bedtime.
  • If your child is having trouble falling asleep or is waking up at night, take a look at their daily habits and make sure to create a good sleeping environment.


Naître et grandir

Scientific review: Évelyne Touchette, Ph.D., professor/researcher and sleep expert
Research and copywriting: The Naître et grandir team
Updated: December 2022




Sources and references

Note: The links to other websites are not updated regularly, and some URLs may have changed since publication. If a link is no longer valid, please use search engines to find the relevant information.

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