All about sleep (and why what you think you know is probably wrong)

Sleep (or lack thereof) is such a big subject for parents. Find out all about the science of sleep and why what we see as a normal sleep pattern may not be so normal after all.

Table of Content

How much sleep do babies need?

Sleep is an essential and recurring condition of body and mind in which the nervous system is inactive, the eyes closed, the postural muscles relaxed and consciousness practically suspended [1].

Sleep is especially important for babies and children as it directly impacts on their mental and physical development [2].

In the course of one night, adults and children move through repeating cycles of quiet (NREM) and active (REM) sleep. For babies, these cycles last around 30-50 minutes and then gradually change and increase in length throughout childhood [3].

Every baby is unique and will have different sleep needs, which may vary from what is considered “normal” [4].

Scientists actually know relatively little about baby sleep requirements. The sleep charts that you see in parenting books and websites are often based on how much time parents  – typically, Western parents – say their babies spend sleeping rather than scientific evidence [5].

How much sleep are babies really getting?

In 2003, Iglowstein and colleagues published a study in Pediatrics Journal titled Baby sleep requirements: Evidence from a longitudinal study. In it they tracked 493 Swiss children from birth to 16 years and observed their sleep patterns. Below are the sleep patterns they observed for children under the age of two years and may serve as a rough guide to baby sleep requirements [6]:

One month old:

  • The average baby got a total of 14-15 hours of sleep
  • 50 percent of babies got between 13 and 16 hours sleep
  • 96 percent of babies got between 9 and 19 hours

Three months old:

  • 50 percent of babies got between 13 and 16 hours of sleep
  • 96 percent of babies got between 10 and 19 hours of sleep

Six months old:

  • The average baby got about 14.2 hours of sleep
  • 50 percent of babies got between 13 and 15.5 hours of sleep
  • 96 percent of babies got between 10.4 and 18.1 hours of sleep

Nine months old:

  • The average baby got about 13.9 hours of sleep
  • 50 percent of babies got between 12.8 and 15 hours of sleep
  • 96 percent of babies got between 10.5 and 17.4 hours of sleep

One year old:

  • The average baby got about 13.9 hours of sleep
  • 50 percent of babies got between 13 and 14.8 hours of sleep
  • 96 percent of babies got between 11.4 and 16.5 hours of sleep

18 months old:

  • The average baby got about 13.6 hours of sleep
  • 50 percent of babies got between 12.7 and 14.5 hours of sleep
  • 96 percent of babies got between 11.1 and 16 hours of sleep

Two years old:

  • The average baby got about 13.2 hours of sleep
  • 50 percent of babies got between 12.3 and 14 hours of sleep
  • 96 percent of babies got between 10.8 and 15.6 hours of sleep

For a more personalised estimate of baby sleep requirements, you need to consider your own baby’s behaviour and observe what times of day she seems sleepy and what her behaviour is like when she wakes up in the morning [7].

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How is baby sleep different to adult sleep?

Babies are not born with sleep patterns adapted to the circadian rhythm, the sleep-wake cycle of day and night that adults rely on. Instead, newborns’ sleep-wake cycle is determined by their need to be fed, changed and nurtured [8].

Their sleep-wake cycle will gradually begin to change around the six week mark, and by three to six months most infants will generally have  adapted to a regular sleep-wake cycle reflective of our own day and night cycle [9].

For adults, around 80 percent of our sleep in the early part of the night is quiet (NREM) sleep. About halfway through our normal-length sleep our sleep cycle flips and by morning, about 80 percent of our sleep is active (REM) sleep [10]

Newborns, on the other hand, spend 50 precent of their sleep time in active (REM) sleep, characterised by fluttering eyelids, rapid and irregular breathing, occasional body movements and grunts or brief cries. This can result in more regular waking [11].

It can take up to two years for a baby’s 30-50 minute sleep cycle to develop towards the average 90-minute adult cycle [12].

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Why d0 babies wake more often than adults?

Newborn babies are wired for survival and wake to be fed, changed and nurtured. When and how often a baby wakes is not influenced by circadian rhythms, as it is in adults [13].

Our circadian rhythms follow a 24-hour clock and control physical, mental and behavioural changes. They are largely cued by the external environment, especially the dark (night) and light (day). Sleep-wake cycles, hormone release, body temperature and other important bodily functions can all be affected by circadian rhythms. When eyes see darkness it cues the brain to release melatonin, a natural sleep hormone. Sleep patterns develop with time, and as a baby gets older her biological clock and nervous system mature, which makes getting her into a routine on par with our own much easier [14].

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Do bottle fed babies sleep better than breastfed babies?

The Australian Breastfeeding Association advise on their website that there is no evidence to suggest any difference between breastfed babies and those fed artificial baby milk with regard to the age at which they sleep through the night [15].

However, findings from a 2011 study titled Long-Term Relationship Between Breastfeeding and Sleep, presented at the American Academy of Pediatrics (AAP) National Conference and Exhibition, suggested that three- to 12-month-old bottle-fed babies do wake less often at night, and sleep for longer stretches than breastfed babies of the same age. However, there were no distinct differences in the total amount of sleep from each group, and at the age of 18 months there were no differences in sleep skills at all [16].

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How does baby sleep differ around the world?

There are some significant differences in baby sleep in various parts of the world. Traditions, cultural values and local conditions and environments all have a bearing on these sleep practices and attitudes [17]. For example:

  • Bedtime: The preferred time to put baby down for her night sleep varies widely throughout the world. While the average baby bedtime in Australia is between 7pm and 8pm, families in Europe and Asia, for example, routinely put their babies and toddlers to bed at around 10pm or 11pm  [18].
  • Co-sleeping: In the Western world, for a whole range of medical, social and practical reasons, co-sleeping is no longer as prevalent as it once was. We tend to sleep our babies in cribs and sometimes in separate rooms. But in some countries parents and children share the same bed for several years. This is the case in many Asian countries – babies sleep with their parents until they’re toddlers, and at that point, they move to their own small bed near their parents’ bed [19].
  • On-the-go sleeping: While many parents in Australia and elsewhere work hard at establishing predictable, regular schedules for baby, there are others who focus on getting out and about with baby in tow. Strollers never crowd Danish cafes because babies nap peacefully outside in their prams. In fact, the Danish National Board of Health specifically recommends the practice, believing that babies sleep more soundly, eat with more gusto and are more alert after an outdoor kip [20].
  • Baby sleep training: In the West, we’ve become fairly accustomed to the concept of sleep training. The idea that some parents take steps to train, or to teach, their babies to sleep is understood and accepted. But in other countries, the idea of “teaching” a baby to sleep is a foreign one. Many parents around the world report that in their home countries, allowing a baby to cry, even for a moment, is considered cruel and unnatural. Instead, it’s the expectation that babies will have night wakings and the family’s “village” will help, whether it means getting up with the baby at night or allowing Mum to nap during the day [21].

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How have perceptions of baby sleep changed?

Baby sleep has been the subject of significant change and controversy since the industrialisation of Western societies. This emerged as a result of the influence of dominant religious beliefs, scientific and medical advancements and general social prosperity [22]. Below are two such changes:

Baby sleep training

Over time, Western culture experienced a move from gentle and more primitive approaches to promoting healthy baby sleep to practices of ignoring the cries of infants in an attempt to teach them to self-soothe [23].

Letting babies “cry it out” is an idea that has been around since at least the 1880s, when the field of medicine had made significant scientific headway in understanding germs and transmitting infection and so took to the notion that babies should rarely be touched [24]. The Ferber Method is a controversial modern approach to this theory, developed by Dr. Richard Ferber in 1985 to solve infant sleep problems. It involves “baby-training” children to self-soothe by allowing the child to cry for a predetermined amount of time before receiving external comfort [25]

In her bestselling book Save our Sleep, Australian child expert and author Tizzie Hall employs a structured, no-nonsense approach to baby sleep. However, she does not  advocate the use of the Ferber method because it can result in the child’s distress  [26].

In addition, Australian parenting expert and author of Sleeping Like a BabyPinky McKay’s approach to babies and sleep is to offer families gentle, responsive and commonsense baby care techniques that encourage the natural development of the child. She believes that while it’s helpful to have practical strategies to settle your baby so they can sleep better within the realm of what is normal and healthy, the most commonly offered “one size fits all” approaches to baby sleep management – such as the Ferber method – are really no more than the “economic rationalism” of parenting [27].



In ancient times, co-sleeping was a necessity for the survival of the baby and may very well have been important for the safety of the tribe itself – a baby’s cry might alert predators, so sleeping with the baby and soothing the cries kept the tribe safe. It also met the immediate needs of the baby, who was kept warm and could feed from the mother’s breast as and when required [29].

In recent years there has been a resurgence in the prevalence of co-sleeping in Western societies. This may be influenced by the rise in popularity of attachment parenting – or “natural” or “instinctive” parenting, as it is also called – which focuses on building a strong relationship between parents and child. It is a movement led by famous paediatrician and author Dr William Sears. Co-sleeping has an important role to play in this approach, which minimises separation from the baby in the first few years of life and is an ancient practice [30].

Research suggests that co-sleeping families actually tend to get more sleep. This was determined by research presented in 2008 titled What to do about sleep? A survey of parents’ experiences with sleep interventions and popular advice. It found that co-sleeping families were less likely to believe their infant’s sleep was problematic than non co-sleeping families. Those with the greatest levels of stress or concern associated with sleep were non co-sleepers. This suggests that responding to a baby who sleeps separately is substantially more stressful than the alternative [31]

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Find more on babies and sleep at Kidspot

Find more on babies and sleep




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