Healthy Sleep Habits, Happy Child
Sleep Duration
December 21, 2020

Found in age groups

Healthy Sleep Habits, Happy Child

5th Edition: 
A Step-by-Step Program for a Good Night's Sleep

Buy now

Healthy Sleep Habits, Happy Child

5th Edition: 
Chapter 1 (only 16 pages!) outlines everything you need to know about your child's sleep.

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A Healthy Child Needs a Healthy Brain, A Healthy Brain Needs Healthy Sleep

Sleep is serious business. If you have not already done so, please read Blog Posts 1 through 5 that describe how sleep is important and beneficial, from the point of view of the United States of America Department of the Army. A major point, emphasized by the Army, is that more sleep produces more benefits for Soldiers:

“Sleep duration is paramount because the health and function of the brain is primarily a direct function of the amount of sleep obtained-the more sleep obtained the better.”

“Cognitive ability and readiness vary as a direct function of the amount of sleep obtained. The more sleep Soldiers [Children] get, the greater their mental acuity, with faster response times, fewer errors, and fewer lapses in attention. Also improved are judgement, problem-solving, situational awareness, mood, resilience, and general well- being.”

“The relationship between sleep duration and cognitive readiness (and thus military effectiveness) is best thought of as a continuum, with more sleep always producing improved performance.”

“Even for those who regularly obtain the generally recommended number of hours of sleep per night, more sleep can result in even better alertness and mental acuity…Insufficient sleep degrades the brain’s function. The more sleep the brain gets, the better it functions…Insufficient sleep negatively effects not only cognitive performance, but emotional and social functioning…In short, the brain has a physiological need for sleep, and sleep promotes the ability to think and maintain mental toughness. And the more sleep, the better. Although obtaining ample and regular sleep generally results in the ability to sustain normal levels of alertness and performance during the daytime, obtaining even more sleep results in greater brain readiness-enhanced mental sharpness and resilience in the field.”

Also, more sleep produces more benefits for children. Even small amounts of extra sleep help. At every age!

Blog 6Sleep Duration


When children, like Soldiers, get more sleep, even if it is only a few minutes each night, there are many benefits. It may take some time to see the benefits, but sometimes, the extra sleep produces benefits immediately, even overnight.


We tend to not appreciate the power of small changes. What we do day by day often has a rhythm, and there is a natural temptation to assume that small changes in our routines are probably not very important. It’s human nature for adults to vary our patterns of behavior by several minutes and correctly think, “What’s the big deal?” In our young children, however, this may be a fallacy, because biologic processes often operate as if they were a finely tuned machine with many interacting parts. Like the famous “butterfly effect” in meteorology, in which the movement of a butterfly’s wings in Asia produces a hurricane in the Midwest, an extremely tiny change may produce dramatic damage.

Here is another helpful analogy. Our healthy body temperature is about 98.6 degrees Fahrenheit. When our temperature is greater than 104 degrees, it usually means that there is a serious or perhaps life–threatening illness. However, when our temperature is only slightly elevated, say 99.6 degrees—-an increase of just over 1 percent—-we still might have a life–threatening disease! A low fever does not necessarily mean a mild medical problem. The thermometer is a useful tool that measures body temperature, but it does not tell the whole story.

Unfortunately, we do not have a “sleepometer” to measure sleepiness. Nevertheless, consider that the work of healthy sleep is to keep the nerve cells in the brain functioning optimally. What happens if your child needs ten hours of sleep but you keep him up just an extra twenty minutes later every night? Twenty minutes seems like a small amount, but this represents a 3.3 percent loss of sleep every night.

A little less sleep each night might be harmful causing brain damage. But the brain is resilient and adding a little more sleep each night will have a cumulative effect and restore brain health.


There are four types of studies proving that just small amounts of extra sleep help children. All these papers were published in peer-reviewed scientific journals.

  1. Moving middle-school and high-school start times later allows students to sleep in later and get more sleep.

Delaying school start times caused 15-year-olds to sleep in later and five months later, they demonstrated improved mental health, better prosocial behavior, peer relationships, and attention level but the average increase in night sleep was only 2.4 minutes.

Lower levels of sleepiness and improvement in alertness and well-being among 15-year-olds was observed in another study of delaying school start times. The increase in night sleep time after nine months was just 10 minutes. Similar results were observed in three other studies involving delaying school start times with an additional 17 minutes, 29 minutes, and 34 minutes more sleep producing less sleepiness, less tardiness, and increase in grades.

In an additional study, a 15-year-old was “classified as having  low mood if he answered “yes” to the following question: During the past 12 months, did you ever feel so sad or hopeless almost every day for two weeks or more in a row that you stopped doing some usual activities?” Delaying the school start time caused a significant reduction of almost 5 per cent of the prevalence of low mood with a 30-minute increase in sleep duration. Also, in this study, among 13-year-olds, starting school earlier caused a decrease of sleep duration of 15 minutes and a 2 per cent increase in low mood prevalence. So, a few minutes less sleep every night also makes a big difference!

  1. Experiments in sleep laboratories using either sleep extension or sleep restriction.

Experimentally extending sleep by adding one hour in bed for five nights caused adolescents to sleep 13 minutes more at night with a reduction of insomnia and depressive symptoms.

Separately, adding one hour in bed for five nights in children 7 to 11 years-old provided an additional 27 minutes of sleep with improvements in emotional lability and restless-impulsive behavior. 

  1. Studies focused on concurrent effects.

Parent-set bedtimes among 14-year-olds caused an earlier bedtime which was associated with an extra 19 minutes of night sleep which caused improved daytime functioning. 

Another study of 7 to 11 years-old showed that 18 minutes of extra sleep caused improvement in grades for mathematics and languages.

  1. Studies of longitudinal outcomes.

When 6- and 8-year-olds sleep 30 minutes less than their peers, they are more likely to have symptoms of psychiatric disorders two years later. 




  1. Dr. Weissbluth,

    I purchased your book Healthy Sleep Habits, Happy Child and I cannot find an answer I’m looking for. When baby is put down for a nap, how long do I let them sleep for? Until they wake? My 3 month old naps for long periods of time and I am unsure if I need to wake him. I’m hoping you can answer this for me. Thank you for your time and help.

    1. In general, never wake a sleeping baby.
      Rarely, to get an early bedtime or correct a messed up sleep schedule, usually after 6 months of age, a parent might wake a baby from a nap.

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