To-your-health: Sleep: effects on development and behavior

December 01, 2019 - 22:27

Quality sleep promotes child development and helps with learning.  Conversely, not getting enough sleep can affect your health, as well as affect your memory, logical reasoning, behavior and ability to control your emotions.

Dr. Phillippe Jean Collin. — Photo courtesy of Family Medical Practice

By Dr. Phillippe Jean Collin*

At the end of a wonderful summer and as families are returning to school and new routines, the question of “How much sleep does my child need?” might arise if you find your child is struggling.

When infants, children, teens and their families come to consultation with fears about behaviour, mood and school performance issues, parents often have many theories for what is causing the problem. As parents, we tend to imagine the worst. A thorough evaluation should include an assessment of a child's sleep habits.

Quality sleep promotes child development and helps with learning. Conversely, not getting enough sleep can affect your health, as well as affect your memory, logical reasoning, behaviour and ability to control your emotions.

How many hours per night?  

The benefits of a good sleep

The consequences of a lack of sleep

For a soothing sleep

How many hours per night?

The number of hours of sleep varies from one child to another. Generally, until the age of 5, your child will need 10 to 12 hours per night and perhaps a nap during the day (from 4 years old, 3 out of 4 children no longer have a nap). From the age of 6 to about 12, a child will need 10 to 11 hours of sleep a night.

  • The best way to know if your child is sleeping well is to watch for signs of sleep deprivation:
  • They are very difficult to wake up in the morning;
  • They lack concentration and are clumsier;
  • They are irritable, sullen, and grunts or cries for no reason; they are more impulsive or more aggressive;
  • They are not interested in what they usually like;
  • They become noisier and more hyperactive;
  • They are often sick.

Sleep, in short

The body has an internal clock that controls the alternation of sleep and wake during a 24-hour day. This internal process is called the circadian sleep-wake rhythm. It is influenced by various signals, such as those of light and darkness. To properly meet the sleep needs of an individual, it is therefore important to know what elements of the environment can help or hinder this essential rest period. Night sleep has 2 phases:

slow sleep, which includes periods of light sleep and deep sleep. During this type of sleep (and more particularly in deep slow sleep), the brain waves are slower and wider;

paradoxical sleep, which is the phase during which the brain dreams. It is called paradoxical because, although the individual sleeps deeply during this phase, the activities of his brain are similar to those observed in the waking state.

These two combined phases constitute a sleep cycle that lasts about 90 minutes and is repeated 6 to 8 times per night in the child (according to the duration of his sleep).

The benefits of a good sleep

Sufficient sleep, in number of hours and in quality, helps the child's development and learning. It is while sleeping that the child cements everything he has learned in his day. Sleeping enough allows your child:

  • to reinforce learning, in terms of both language and motor skills, information learned and strategies to solve a problem;
  • to make better use of his logical reasoning; to better manage his emotions;
  • to stay alert during the day;
  • to focus more and longer; to develop well on the physical plane;
  • to strengthen your immune system.
  • The consequences of a lack of sleep

Conversely, not getting enough sleep can affect many aspects of a child's development. When a child lacks sleep, they may have:

  • difficulty managing emotions, and therefore mood swings, being impulsive, aggressive or tend to be depressed;
  • a less lively mind;
  • more hyperactive behaviour;
  • difficulty staying attentive and focused;
  • tendency to eat less well and gain weight.

For a soothing sleep

There are several things that can affect your child's sleep.  If he has trouble falling asleep or wakes up at night, pay attention to certain lifestyle habits.

Sleep schedules

It is recommended to keep bedtime and sunrise constant and not to deviate too much and as far as possible, the weekend also, especially for children who have sleep problems.


In order to prepare your child for sleep, it is advisable to plan a routine to do with him every night before he goes to bed. This routine can last from 20 to 30 minutes. It is important that this routine be done in a positive and relaxing way. To learn more, check out our sleep sheet: the importance of the ritual routine sleep.


The brain needs a time of adaptation between intense activity and sleep. It is therefore best to finish lessons and homework before dinner or in the early evening to enjoy a quieter activity before bedtime.


Your child needs to spend his energy, but it is better to book more challenging activities for the day (running, jumping, climbing, etc.) and doing quieter activities in the evening.


The computer, mobile devices (tablets and phones) and television are to be avoided before bedtime. Not only do the screens stimulate the brain too much before sleep, but their brightness promotes the awakening of the brain instead of rest. Your child should not have a TV, computer, or video game in his room either.


It is recommended to avoid exciting foods in the evening, such as anything that contains caffeine, including chocolate, tea and some energy drinks. In addition, it is best to wait 1 hour or 2 hours after a meal before going to sleep, because digestion can disrupt sleep. In contrast, an empty stomach can also prevent the child from sleeping well. It may be beneficial to have a healthy snack. — Family Medical Practice

*Dr. Philippe Jean Collin is a French Pediatrician with Family Medical Practice Hanoi. He is a member of the French Society of Pediatrics, American Society of Nephrologists, and the Pediatric Academy Societies.

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