A Guide on Sleep and Growth for Kids

Written by Kaitlin Cushman, Healthy Height’s In-House Nutritionist 

By the time a child is 2 years old, they have spent 40% of their life thus far asleep (1). In our lifetime, we will spend at least one-third of our lives asleep! Sleep is incredibly important for our health - it is a time for the brain to recoup and reconcile information from the day, as well as a time for the body to rest (2). For the most part, children need sleep for the same reasons that adults do, however it is most important for ensuring proper physical growth and development. This relationship between sleep and growth is connected by Human Growth Hormone (HGH).

Before discussing HGH’s role in growth and sleep, first let’s review what we know about the human sleep cycle and what happens at each stage.

Sleep and Its Cycles

There are 5 stages of sleep that the human body cycles through multiple times each night. Scientists used to believe that sleep was a passive act and that the brain was essentially shut down while we slept. Today through scientific research, it is known that each stage of the sleep cycle has the brain actively cycling through various activities (4).

Stage 1

The first stage of sleep is when you begin to feel a bit drowsy, but just starting to drift off to sleep. A person in this stage of sleep can easily be awoken or have their sleep easily interrupted; they may not have even realized they were dozing off. This stage can last from 1 to 7 minutes (4,5).

Stage 2

This second stage is when you are truly beginning to sleep. While sleeping has begun and the muscles and brain have begun to relax, someone can still very easily be alerted to something and wake up quickly. If sleep is interrupted in this stage, there should be no problem rising and responding. This stage of sleep last about 10 to 25 minutes (4,5). 

Stage 3 & Stage 4

In stages 3 and 4 you have now reached what is considered deep sleep. This is when the brain and body are doing what they need to rest, recover, and prepare for the next waking period. Sleep in these stages is so deep and restful that waking up would be difficult. If someone is suddenly awoken from a deep sleep they may be disoriented or clumsy because the mind and body wasn’t prepared to be active again. These periods of sleep lasts 20-40 minutes (4,5).

Stage 5 (REM Sleep)

The 5th stage, also known as the Rapid Eye Movement (REM) stage of sleep, is the period of sleep when dreaming occurs. The brain is very active during REM sleep while the body is essentially paralyzed from moving. REM sleep periods are shorter at the beginning of the night and get longer once sleep has extended beyond 6 hours. This stages last from 70 to 120 minutes depending on the length and quality of sleep (4,5).

Scientists are still researching sleep to better understand the purpose of the various brain activity that occurs in its 5 stages. However, we do know that quality sleep is necessary for good physical and mental health throughout life and in childhood, detrimental for physical growth. 

Human Growth Hormone and Sleep

Human Growth Hormone, also known as HGH, is part of the endocrine system and is excreted by the pituitary gland. The production of HGH is influenced by nutrition, exercise, and stress (6). Adequate levels of HGH are necessary to support proper growth and development of bones and tissues during childhood. 

So why does sleep matter when it comes to growth? While HGH is released during both exercise and sleep, an overwhelming majority of the hormone is released during the deep sleep of stages 3 and 4 (2). If a child’s sleep pattern is irregular or sporadic, their body will not have the opportunity to let HGH do its important work to help their body grow.

How Much Sleep Does My Child Need?

Children need a lot more sleep than adults due to the relationship between sleep and growth. Children ages 3-5 years need 10-13 hours of sleep and those 6-13 years of age need 9-11 hours of sleep (7). Ensuring your child gets enough quality sleep crucial for promoting adequate growth and maintaining good mental and emotional health. 

Tips for Improving your Child’s Sleep

It is not uncommon for children to experience issues with sleep from time to time. Depending on their diet, exercise, and mental health, the ease getting to sleep and staying asleep can vary. There are ways in which you can help your child get better sleep.

Here are some tips for helping your child improve their sleep pattern:

  • Limit screen time around the time they go to bed- the bright lights of a cell phone, television, or computer can cause problems for your child when they are first trying to fall asleep.
  • Consistent bedtime routine- at the very least, having a consistent bedtime for your child each night helps to cue them when it is time to get some sleep (8). Additionally, keeping the other pre-bedtime activities as part of the routine (i.e. bath time, story time, etc) help to reinforce the general notion that it is time to transition for bedtime.
  • Your child’s room should be peaceful- your child’s room should be kept calm and conducive to sleep. Additionally, never make going to bed a punishment (8). Your child should see going to bed as a restful and rewarding experience that recharges them, not something they associate with getting into trouble.
  • Keep activities around bedtime calm- like the importance of keeping a routine, it is ideal that activities around bedtime don’t get them so hyped that they are too excited to get to sleep. 

Nutrition and Sleep

The connection between nutrition and growth has been well established from clinical research. However, the association between nutritional intake and sleep patterns has not been as well studied. As part of our 6 month clinical study investigating the effects of Healthy Height’s nutrition on linear growth, we assessed sleep as a secondary outcome of the study. Through sleep assessment questionnaires, sleep duration and time to sleep was recorded for the participating children (9). The sleep data was analyzed along with food diary information to evaluate whether nutritional intake had an effect on sleep patterns. 

From the analysis, a positive correlation between sleep duration and nutritional intake was identified. Sleep duration was positively correlated with caloric and macronutrient intakes. Additionally, an association was found between faster time to sleep and those who were ‘good’ consumers of the Healthy Height formula - consuming at least one serving per day (9). 

What can be concluded from these findings?

While more research is needed to truly understand the role of nutritional intake in sleep patterns, our findings support previous sleep and nutrition studies by suggesting that that better nutrition is associated with better sleep patterns (9). 


  1. National Sleep Foundation. “Children and Sleep.” National Sleep Foundation. https://sleepfoundation.org/sleep-topics/children-and-sleep, 2018.
  2. Forstl, Hans.”SLEEP: Why do we sleep one third of our time?” Technologist. http://www.technologist.eu/why-do-we-sleep-one-third-of-our-time, 2015.
  3. Tuck. “Sleep and Human Growth Hormone.” Tuck: Advancing Better Sleep. https://www.tuck.com/sleep-hgh/, 2018.
  4. Healthy Sleep. “Natural Patterns of Sleep.” Harvard, http://healthysleep.med.harvard.edu/healthy/science/what/sleep-patterns-rem-nrem, 2007.
  5. The Center for Sound Sleep. “The Science of Sleeping.” Center for Sound Sleep. http://www.centerforsoundsleep.com/sleep-disorders/stages-of-sleep, 2018.
  6. BabyCenter. “The connection between sleep and growth (ages 5 to 8).” BabyCenter: Expert Advice. https://www.babycenter.com/0_the-connection-between-sleep-and-growth-ages-5-to-8_3658990.bc, 2017.
  7. National Sleep Foundation. National Sleep Foundation Recommends New Sleep Times.Nationalsleepfoundation.org. 2015.
  8. Przeworski A. “8 Tips to Improve Your Child's Sleep.” Psychology Today. https://www.psychologytoday.com/us/blog/dont-worry-mom/201310/8-tips-improve-your-childs-sleep, 2013.
  9. Yackobovitch-Gavan M, Machtei A, Lazar L, Shamir R, Phillip M, Lebenthal. Randomised study found that improved nutritional intake was associated with better sleep patterns in prepubertal children who were both short and lean. Acta Paediatr. 2018 Apr;107(4):666-671.