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

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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.

  2. Hi Dr. Weissbluth,
    I am a big admirer and adamant follower of your method! We recommend your book to all our friends and acquaintances who are having babies, and even those with toddlers who still have night awakenings or bedshare with their parents.
    Anyway, I wanted to get some advice on baby #2- we have decided to start sleep training a bit earlier with this one due to the fact that there is now a toddler to contend with, and due to our second son’s colicky start. He was induced at 37 weeks due to a diagnosis of maternal cholestasis.
    Our son took contact naps and motion naps in the swing the majority of his life (they usually lasted 2-3 hours but were inconsistent), but he was able to sleep in his bassinet from 9pm-2:30am, be fed, then return to sleep until 5am and eat again.
    We have established a decent nap at 9ish am, that lasts up to 2.5 hours at times, and another nap around 12:30 that lasts 1-3 hours as well. I do let him cry for about 10 minutes with each of the naps, check in with him, reposition and replace pacifier, then leave and see if he will sleep. He usually is asleep in less than 20 minutes total. When he isn’t, I usually decide to rescue the nap by holding him so as to not negatively impact the night time.
    However, what I am finding is that my baby (10 weeks, 7 weeks adjusted for sleep) is yawning almost all day, and it starts once he wakes up and consistently continues on. Also, he likes to rub against a blanket and have a paci in while he sleeps. Do I need to take those things away? Should I also unswaddle him? If I choose to leave those comfort things behind, will I need to re-sleep train him once those items will need to be faded out?
    My final question is this- Can too much daytime sleep at this age interfere with adequate feeding? I found that on days when my little guy slept 2/3 hour long naps, and went to bed early (6:50PM), he awoke every 3 hours to nurse hungrily and consume full feedings each time, then immediately fall back asleep.
    Today, he awoke at 3:20 pm from his second nap and is showing sleepy cues, I put him down drowsy but awake and he cried and never fell back asleep for this “No cry nap”. Do I aim for a 5:30 bedtime on days like this despite him having sleepy cues starting at 4:15/4:30? I am afraid of the overtired second wind coming from being awake for over 2 hours at bedtime if I don’t interject a nap in between.
    Thank you!

    1. At 6 weeks of age, adjusted, a baby’s brain wants an earlier bedtime and there is also around this time peak wakefulness, fussiness, and crying and sometimes, naps deteriorate. Because you have two children and number two had colic, my suggestion is to consider the following, if, and only if you feel comfortable with this and can commit to 3-5 nights:
      1. No new nap starts at or after 3pm. If he’s asleep at 3pm, don’t wake him.
      2. Strict 5:30pm falling asleep time ( you have bathed him, fed him, soothed him, and you are leaving the room with lights out at 5:30pm).
      3. Extinction at night with the expectation that there will be one feeding sometime after 9:30pm and another feeding at least 4 hours after the first feeding. A very early morning feeding may also occur. Are you breast feeding? if so, is your milk supply ample?
      4. Do whatever works to maximize day sleep and minimize daytime crying. No strict nap schedule for now.
      5. Keep a detailed record of day sleep, night sleep, etc.
      Let me know your thoughts.

  3. Hi There,
    Coming back significantly later, we wanted to let him get past the rest of his “colic” and fussiness as he was still experiencing a lot of gut issues at this time. At 15 weeks old, we saw the “colic” essentially disappear, and within a few days decided that it was time to implement your method. At this point, Charlie was sleeping 2 sometimes 3 hours during his naps, and waking 3x a night to eat and going back down well by himself following these feedings. He however insisted on rocking all the way to sleep with numerous fruitless attempts to be placed down into his crib, waking back up, and demanding more rocking… this turned into a full time job that I wasn’t interested in keeping long. Despite that, I kept up, and he was sleeping well. Usually about 10.5 hours a night and between 3-5 hours of napping a day, but his time of falling asleep was 9 PM most nights which definitely wasn’t something we were thrilled about.
    At 15 weeks we started implementing the “sleep training” with early bedtime. Earliest we could muster was 6 PM due to work schedules.
    Day 1, I put him down after his soothing at 6PM and left the room. He cried for 59 minutes exactly then fell asleep, slept until 11PM and woke for a feed, another at 2:30 and another at 4:30. He cried for an hour after I put him down from 4:30 feed, but I let him go on with it. That morning, he woke up at 7AM and I put him down for a nap 8:30, he slept from 8:40-9:30. We continued the short naps that day and tried again for an early bedtime.
    Day 2 -6 PM; This time he went down to sleep, and cried for 25 minutes, but it was mostly whining and complaining, no expansive episodes of wailing. He woke up at the same time intervals that night, but didn’t have any profuse crying issues after night feedings. He woke up at 650 AM, and was put to bed at 840 am for a nap, fell asleep independently until 0850 and woke up at 1035 am. His second nap was noon until 2:42 pm. He was unable to stay awake past 430PM no matter how hard we tried, and he fell asleep and woke up at 514PM.
    Day 3- We had to push back bedtime to 7PM because he wasn’t tired at 6PM This seemed to be ok for him. He woke up at 1AM for a feeding, then again 5AM for a feeding, and woke up at 650 AM. He was put down for a nap at 0838, my husband was home that day and stated that he seemed very tired earlier than the other days. He woke up at 0915, but seemed grumpy to my husband who helped him back to sleep and put him back down at 0944. He then slept all the way until 130 at which point, my husband woke him to feed him. He was tired and returned to sleep at 2:40pm until 3:20PM. He had a short nap from 450PM until 520PM.
    Day 4- bedtime had to be 7PM to accommodate the 520 ending of a nap, and to try to keep things relatively early. Charlie woke up at 730PM and didn’t fall back asleep in his crib until 8PM. He woke for a feed at midnight, and again at 230am, and both times I believe my husband helped him back to sleep. He woke up for the morning at 0636AM, and was put to bed around 0840AM, fell asleep at 0851. He woke up at 0933 and didn’t extend his nap in the next 30 minutes but quietly lay in the crib. He went back to sleep at 11:23 AM and woke up at 1:11PM. Per my sitter, he was tired at 240 so she put him down and he fell asleep at 251PM and slept until 320, and did not extend his nap but laid quietly in the crib until 350PM. Since this time was closer to 4PM, and he seemed content, I kept him awake using bathing and going outside this afternoon to attempt to re-try the early 6PM bedtime.
    Day 5- bedtime 6 PM, asleep by 0605. Wide awake at 640PM. He laid in his crib wide awake from then until 8PM without sleepy signs. I picked him up and played with him, fed him, changed him, and put him back down at 8:54 PM. I am writing this now, and have no clue how the rest of the night will play out.

    I am curious about why he seems to wake up shortly after being put down to sleep, usually within 20-30 minutes of bedtime for two days now. His naps seem pretty irregular right now and having a strict set bedtime seems very difficult. Day 2 seems like him most “ideal” sleep day so far.
    The interesting thing is, since his stomach issues have passed, he is now extremely happy and even tempered at all times. After waking early from naps, he is usually happy in his crib to look around without asking to be picked up, and we would never know he’s awake if not for the video monitor.
    In hindsight, I think that the bright lights in our bathroom during bath time might be a factor… I think they might be stimulating him before bedtime instead of allowing his melatonin levels to peak. I will be eliminating that factor this weekend.
    Is it possible that at now 16 weeks old, 13 weeks adjusted, he is ready to be awake for more than 2 hours at a time? Or are we keeping his awake times too broad by not putting him to bed earlier between naps? I think for being a colicky boy, he has managed to be well rested, and he responded to extinction in record timing within less than 3 days which was a huge shock to me. Based off his temperament… I am having difficulty reading his drowsy cues as he’s constantly smiling and cooing.
    I’d like to find a more consistent sleep schedule for him that would help achieve some predictability in my life, and I would also like to help to wean back some of those night feeds more as well. The “false start” bedtimes seem a hurdle to that at this time. What do you suggest? Is this simply developmental?

    1. Are you breast milk or formula feeding?
      Here are some observations that might, or might not be important, for you to comment on:
      “Day 3- We had to push back bedtime to 7PM because he wasn’t tired at 6PM…my husband was home that day and stated that he seemed very tired earlier than the other days. He woke up at 0915, but seemed grumpy to my husband who helped him back to sleep and put him back down.” Because the bedtime was too late, his behavior was off the following morning.
      “Day 4- He woke for a feed at midnight, and again at 230am, and both times I believe my husband helped him back to sleep. Extinction means you do not “help him back to sleep.” Well-fed infants might need to be fed 4 hours after a feeding, not sooner.
      Please review the section on ‘Extinction’ and tell me if you are comfortable with doing this.

  4. Thank you for that response, your points definitely warrant more attention from us.
    I am bottle feeding him, he gets formula. He is a small portion eater as I believe he became accustomed to “snacking” all day while he was very young and suffering from colic. He would spit up and scream if he had more than 1-2 oz per feed at that time, and we’ve had a hard time getting his intake up since then. He currently eats about 4.5oz at each feed, about 3-4 hours apart. He weighs 14.5lbs, so he is gaining weight well.

    I am ok with complete extinction, I just need to reinforce the concept with my husband who is a much bigger softie than me. I did use it the first couple nights when I was by myself, but by night 3 or 4 when my husband was home, things became much less predictable due to variable approaches in the night, and attitudes about a nap after 3PM, as I can see now based off my response.

    I will try again with an early bedtime tonight, and see if we can get back on track… we had a rocky night.
    He had gone down at 6PM, woke up at 630PM wide awake and looking around- then stayed awake until almost 9PM and ate at 1230am, and again at 5:30am. I woke him up at 7:10AM to try to keep the 9 AM nap. However, he appeared drowsy to me earlier, so I put him down to sleep by 0820AM to prevent a second wind since the night sleep was so bad. He is sleeping 2 hours and 25 minutes into this nap now, at 1045AM. I do not plan on waking him from any naps today, and I will not allow a new nap to start after 3PM to preserve the early bedtime.
    I reviewed your blog posts on extinction, sleep training success in 3-4 days, and drowsy/fatigue signs so that it is all fresh in my mind.

    I think the biggest hurdle to overcome with this sleep training is our inconsistency in approach and deviation from the rules as we are both extremely tired ourselves, I find coffee wakes up my body, but my mind is about 10 beats behind. I am physically dropping items, and cannot focus. My husband is also struggling as he works in the ER and has variable hours, but usually doesn’t get to sleep until 3AM and is up at 8AM to help me with the kids. I feel we will need to re-sleep train ourselves once this is all said and done.

    1. One thought is to make your husband read the chapter on sleep solutions so that you can pick a sleep solution that you both feel confident with to be consistent. Inconsistency will doom any sleep solution. Maybe take a break now and do whatever you can to get more sleep for both of you without regard to solving your baby’s sleep issues. Then, when your batteries are recharged, consistently execute a sleep solution. Here, often the second attempt is successful because you are better rested, you have a team approach, and maybe you are more highly motivated to stick with it. Alternatively, you execute the sleep plan of your choice with the understanding that your husband does not interfere, no excuses. I wish you the best; please give me a follow-up.

  5. After further review, are going to recommit to extinction! I will keep you abreast of our progress. I am not going to shy away from the very early bedtimes, and even go earlier than 6PM if he cannot stretch further.
    My quick troubleshooting questions that I believe threw me off this last time-

    1. When baby wakes up 20-45 minutes after falling asleep independently at bedtime, and is awake for 1+ hour in their crib without crying, do I go in to keep them awake until they are ready to go back to sleep? Or does this create issues. I would not go in if the baby were crying.

    2. When the baby wakes less than 4 hours from the most recent middle of the night feed, do I allow to cry until 4 hours has passed and then feed, or until 4 hours has passed, baby is no longer crying, and then feed to avoid rewarding crying with food and confusing extinction process?

    These were the only things I was unable to find answers for within the blog or book.
    Thank you!

    1. Because of his age and because you are bottle feeding, I think that feeding him once in the middle of the night and maybe again early in the morning would be sufficient. Most children his age can easily go 4 hours or more between feedings.
      Pages 203 and 558 in my book discuss in detail feeding at night.
      Let me know if you have further questions.

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