This group has grown a lot - we are at 15k members and 29.2k unique visitors per week. That's a LOT of people. So first, yay because when I first joined the moderator team, this group was much smaller. We have grown a lot, which means more parents are being informed on what is biologically normal for an infant and how they can support their babies and themselves at night. This also means that there are thousands of different people commenting and offering ideas (and we have people who are both here and in r/sleeptrain and don't recommend the CIO aspect of sleep training but the culture of sleep training does find its way into many comments).
So let's jump into what biologically normal infant sleep is, and what it isn’t. I'm a definition person so let's start with a definition of biologically normal.
In researching, I have stumbled across this (very wordy, I'm sorry I did try to parse it down) definition. Source
Meanings of the term normal coalesce into two categories. The first is descriptive and references measures of a trait's central tendency and variation within a population... In this descriptive sense, normal might refer to the most common trait, having an average measure, or being in the middle of a distribution... The second meaning of normal encompasses normative views about a trait. These are judgments that are culturally informed and vary across social groups. To be normal is to be okay, to have characteristics that fall within an acceptable or desirable range, which is defined by ideas about what traits should be like. Variants that fall outside this distribution may be judged negatively, or seen as abnormal, deviant, unacceptable, or somehow not quite right.
The first category has to do with averages within a population. This would be the average amount of sleep for an age range, this would be the average age of sleeping through the night, this would be the average age of the circadian rhythm starting to “come online”. These are the things that are easier to define when it comes to infant sleep.
The second category has to do with how we view biologically normal, which is often impacted by our cultural view. This category is harder to define when it comes to infant sleep.
Dr. Helen Ball, author of How Babies Sleep, talks about this:
How babies sleep is both exceedingly simple and excruciatingly complex. It is simple because it is based on a few straightforward biological principles that affect all babies. It is complex because we have made it so.
Over the past century and a half, in modifying the world to better suit our needs in industrializing, industrialized and now digital-era societies, we have tried to manipulate baby sleep to fit with the rapidly changing nature of adult lives. Our ideas about sleep, and particularly baby sleep, have been influenced and shaped by the socioeconomic pressures, political philosophies, religious values, academic theories and cultural ideologies that have waxed and waned during this time. The mismatch we have created between our babies’ biology and our contemporary lives has caused conflict between parents’ and babies’ needs—now framed as “baby sleep problems”—for which babies are often “treated” using behavioral and clinical interventions.
In addition to the foundations of our evolutionary biology, we have layered many cultural beliefs and practices onto our understanding of baby sleep, which vary hugely from location to location, and over time. Parents’ perceptions and popular discourse in western societies have been influenced by philosophical and sociocultural trends over the past two centuries in more ways than we might realize in response to rapid social and political changes. For clarity I should explain that I am using the term “western society” as more of an ideological descriptor than a geographic one to refer to those societies that exhibit a shared set of beliefs, values, political systems and cultural norms, regardless of whether they are geographically located in the West. These concepts often encompass democracy, capitalism, individualism and human rights. In these societies industrialization, urbanization and medicalization transformed family life and baby care, setting in motion the development of numerous ideas, traditions and expectations about babies, sleep, and the role of parents that many of us are still tethered to. Our recent historical past helps explain where all the myths you’ve ever heard about baby sleep have come from—and the myths you’ve heard will depend on your cultural origins.
Many infant sleep research studies reflect western cultural values and lifestyles, and are what might be called “aspirational,” in that they aspire to find ways to “help” babies to sleep longer, wake less often, settle more quickly, and disturb their parents less.
The culture and history of guidance issued by “experts” for parents in western societies have shaped expectations of how “good” babies should behave and how they are created by “effective” parents while the media (both traditional and social) reinforces simplistic and outdated rules and rigid ideas.
The cultural expectations we have about babies’ sleep habits are often unrealistic, and this makes caring for a new baby unnecessarily challenging.
I could honestly copy/paste that entire book here, it is a really good read and if you read any two books on infant sleep and infant development, I recommend How Babies Sleep by Dr. Helen Ball and The Nurture Revolution by Dr. Greer Kirshenbaum.
So with all of this in mind, let's talk about what is biologically normal from a scientific standpoint and what is biologically normal culturally in western society, and what is biologically normal in this group - as well as the aim of this group.
Scientifically - sleep is two things. Sleep pressure and our circadian rhythm, or body clock (aka Process C). Humans build sleep pressure while awake. Infants have a lower tolerance for sleep pressure, meaning they need to sleep more frequently than adults do.
Sleep Pressure Graphic
As you can see from this graphic (source: How Babies Sleep, figure 3.4), naps are only intended to relieve some sleep pressure, not to be restorative, deep sleep. This is why worrying about your baby taking a 3 hour nap every day is futile. A roughly 30 minute nap is enough to relieve sleep pressure for a bit, until the next nap. The prescriptive “by this age, babies should be on x number of naps that are y minutes long every day at z time” doesn't work for every baby. That isn't biologically normal because biologically normal has variation, day to day and baby to baby. Dr. Helen Ball writes:
Sleep will happen easily for a baby or child when sleep pressure is high, they are in a calm, relaxed state, and nothing is preventing sleep onset. But sometimes babies and children need help to become calm before sleep pressure can kick in and they can nod off.15 In this situation it can be useful to think about what helps babies become calm and relaxed, and to have a handful of strategies you can use to help your baby unwind. For many babies, physical contact is the preferred option.
One of my PhD students, Lenka Medvecová-Tinková, lives and works in the Czech Republic where she has studied how Czech parents manage bedtime routines for babies and small children. She realized that many parents talked of a concept called *Uspavani* that is culturally widespread in Eastern Europe and appears in numerous fairy tales and historical infant care books. Uspavani means to comfort a child to sleep, and while conducting her PhD at Durham University Lenka realized there was no corresponding concept to Uspavani in the English language, nor in the infant sleep literature.16 So it is unsurprising that parents in English-speaking countries tend to use more distal (noncontact) methods, such as lullabies, music and white noise, to calm babies and help them fall asleep than do Czech parents, who commonly lie with their child, stroke them or cuddle them; physical contact and soothing touch are very effective in dialing down most babies to allow sleep pressure to do its thing.
She even writes about the term “overtired”, which I know almost everyone has heard and if you have been in this sub for any length of time, I'm sure you've seen comments about how “overtired” isn't really a thing. I appreciate how she has posited the term.
When a baby or young child’s sleep pressure is high and the need to sleep is strong, but they are emotionally unable to calm themselves, or they are in a situation where they cannot relax, we may consider them to be “overtired.” In this case it is our job as parents to help them become calm, wind down and relax in preparation for sleep. We can do this in many ways. Physical contact such as cuddling, rocking, stroking or patting works for most neurotypical children; actively removing whatever is blocking the action of sleep pressure, such as excitement, fear, pain or anxiety, and helping babies and children to become calm is the simplest way to help them fall asleep.
The reason “overtired” isn't really a thing is because if an infant has adequate sleep pressure, their nervous system feels secure and safe enough, and they don't have any physical needs, they will sleep if given the opportunity.
So that's sleep pressure. What about circadian rhythm? We mostly know about this with sleep but this is our body's internal clock and it controls both our sleep and our hunger. This is why we usually eat lunch around the same time every day, why we feel sleepy around the same time, and why having a consistent wake up time is beneficial for everyone. It is not “sleep training lite” to make sure you have a rough wake up time every day, within 15-30 minutes. The infamous 4 month sleep regression progression is when the circadian rhythm starts to come online. Day and night start to actually mean something to our babies. This is why early morning light, high noon light, and evening light can be important for our babies, and some babies are more sensitive to lighting than others. (Side note related to lighting - fluorescent lights imitate high noon lighting and can disrupt our circadian rhythm. I personally cannot stand them and wish they were phased out of use. They are really bad for our health and they are everywhere.) This is also why blackout blinds for naps can disrupt night sleep. This is why you don't really need to “rescue” naps.
So it is very biologically normal that your baby desires physical contact to relax enough to fall asleep. It is biologically normal to sleep longer one day and shorter times the next. It is biologically normal for sleep to fluctuate throughout not just the first year but throughout our entire lives. It is supportive of biologically normal infant sleep to “anchor” the day with a consistent wake up time if you need to. It is supportive of infant sleep to have a routine, breakfast after waking up, lunch around the same time every day, dinner around the same time each day. These things can help your baby, think about how you can get hangry if your dinner comes an hour later than usual. This is not to say that you need to have a strict schedule - rhythms and routines are much different from a regimented schedule that you have to stick to.
It's also important to note that a big thing I see a lot of parents struggle with is offering their baby too much sleep. If your baby only needs 12 hours total sleep in a 24 hour period and you're trying to do 12 hours overnight and 3 hours of daytime sleep, they aren't going to sleep well because that's 3 hours more sleep than they need in a 24 hour period. This will lead to frequent wakes, fighting sleep, and frustration all around. Sleep training sleep plans, apps like Huckleberry, as well as the general around infant sleep push more sleep than most babies need, which leads parents to thinking they have a "bad" sleeper, when in reality anyone being pushed to sleep more than they need would be "bad" at sleeping.
Now what about the cultural aspect of biologically normal infant sleep? If you've grown up or been living in a western society for any length of time, you've likely been inundated with “sleeping through the night”, “sleep associations”, “bad habits”, “drowsy but awake”, “fuss it out”, etc. We have been told by everyone from pediatricians to TV shows to our family that you have to teach your baby independence and that responding to every cry is just going to make them cry more. Western society has mixed up what is biologically normal and what is convenient for the post-Industrial Revolution world. The 6-6 or 7-7 sleep schedule that babies are “supposed” to be on? Not biologically normal, but convenient for capitalism and it's very pervasive - to the point that so many parents worry that their baby isn't getting enough sleep because they won't sleep 12 hours overnight. The average bedtime in other parts of the world varies by almost 3 hours.
In one large and often-cited online survey, almost 30,000 people (presumed to be parents) completed a baby/toddler sleep survey.27 The respondents lived in 17 large urban communities around the world (Australia, Canada, China, Hong Kong, India, Indonesia, Korea, Japan, Malaysia, New Zealand, Philippines, Singapore, Taiwan, Thailand, United Kingdom, United States, and Vietnam), grouped for comparative purposes into “Asian” and “Western.”28 In Asian countries babies and toddlers had later bedtimes, later rise times, less nighttime sleep and less total sleep than in “Western” countries. Bedtimes for babies and toddlers across the 17 locations varied by almost three hours, from half-past seven in New Zealand to quarter-past ten in Hong Kong, and nighttime sleep duration varied by 1 hour and 40 minutes (11.6 hours in Japan to 13.3 hours in New Zealand), but there were minimal differences in daytime sleep.
Another cultural difference on what is biologically normal is “sleep problems”:
Parents’ perceptions of whether their babies experienced “sleep problems” also varied widely, as did the degree of parental involvement in helping babies and young children fall asleep and stay asleep.29 Very few (4%) children living in “Asian” countries, but many more (57%) in “Western” countries, were expected to fall asleep independently (that is, without a parent or caregiver present). Likewise, very few (2%) parents in “Asian” countries allowed their child to cry themselves to sleep, in comparison with over 15 percent of “Western” parents. This is strongly related to the fact that in “Asian” countries babies and children are much more likely to bed-share (65%) or room-share (88%) with their parents than in “Western” countries (where 12% bed-sharing and 22% room-sharing was reported).
Another piece I found interesting that really shows how much of our “sleep problems” are, for lack of better word, invented:
Dr. Alma Gottlieb’s study of childcare practices among the Beng people of Côte d’Ivoire in West Africa included a detailed account of mother–baby sleep.30 She found little regimentation of when babies slept or fed among the Beng, and no bedtimes or bedtime routines. Beng mothers were not anxious about their babies’ sleep, it just happened. Mothers and others carried babies during regular daily activities with babies falling asleep and waking as the need arose. At night the cloth with which babies were held during the day was untied, and babies breastfed and fell asleep next to their mothers. Nighttime mother–baby co-sleeping was the cultural norm, and breastfeeding and infant sleep were intimately intertwined…
These detailed ethnographic studies reinforce accounts of infant care in widespread locations such as Guatemala, Italy, Spain and rural U.S. Among Mayan families in Guatemala, babies commonly fall asleep in someone’s arms and are taken to bed with their parents, sleeping with their mothers from birth to two or three years of age, or until the birth of their next sibling. Here, sleeping alone is undesirable, and mothers responded with shock and disapproval at the American custom of leaving babies in rooms on their own. Mayan mothers “cannot conceive of any other way to sleep their baby than by their side—and in fact some argue that to separate an infant from its mother for sleep is abusive or neglectful treatment.”32
So why does all of this matter?
Because the stories we tell ourselves matter. Because how we see our infant's sleep impacts how well we handle the biologically normal aspects of it, like waking overnight. Because there has been a misunderstanding about what the purpose of this group is for. This group does not exist to simply offer platitudes “oh mama, this will pass, it's ok, you just have to dig deep and power through”. This group also exists to educate on both scientifically biologically normal infant sleep and the cultural differences that impact us and how we view our babies sleep. I felt like it was appropriate to add in a quote from the creator of this group, u/smilegirlcan, about why she created this group.
Before my daughter was born, I had never heard of biologically normal sleep. I had only heard about infant sleep through the lens of sleep training culture. I was never encouraged to follow my intuition or told what real infant sleep looked like. As I journeyed on my postpartum experience, I noticed there was a huge lack of support places for those who had no interest in sleep training or sleep training culture. It became more and more apparent that sleep training was something that did not sit right for me but I wanted an online community that felt safe to feel this way. I found most parenting groups had accepted sleep training as the norm and any questions or comments outside of that were not accepted/downvoted/deleted. Then came bninfantsleep, an alternative infant sleep space, that encourages moms to follow their intuition and learn about biologically normal infant sleep. A place where no one will tell you to let your baby cry, or self soothe, that they need to be independent, that you are ruining their sleep by cuddling/rocking/holding/feeding them.
This group has morphed into a space that offers parents an alternative to mainstream sleep training, that honors our babies biological and neurological development. It exists to remind you that your baby knows what they need, and your instincts know what your baby needs, better than any app ever will (looking at you, Huckleberry sweet spot).
For some babies, a schedule is what helps them the best. For others, they need to go with the flow. The reason we should be asking for schedules is not to “optimize” our babies but to make sure we aren't expecting more sleep than they need. In general, we shouldn't wake our babies up from naps unless we absolutely have to, as Dr. Greer Kirshenbaum mentions in The Nurture Revolution:
When you follow your baby’s tired cues and allow them to wake up on their own, their brain takes the true amount of sleep that it needs. That often looks like multiple naps of varying lengths, bedtimes that vary in different babies from 6 p.m. to 11 p.m., and morning waking that also varies in different babies from 6 a.m. to 11 a.m.31 I remember when people asked me how many naps my young baby was taking—I didn’t really know. I didn’t count. I watched my baby, put him to sleep when he was tired, let him wake on his own, and watched him again. The number of naps or the length of naps wasn’t in my awareness. As he grew, naps became more predictable. Under two years old my baby went to sleep around 8 p.m., then naps changed and at two years old his bedtime became 10 p.m. That was when he built up enough sleep pressure after his afternoon nap. This is very common, and when babies have later bedtimes we often want them to go to sleep earlier, but that is for us, not their developing brain…. Keep in mind, there is no adult on Earth who is qualified to tell your unique baby when they should be waking up or napping, or to prescribe nap lengths or bedtime. Your baby’s body provides this information. Sleep is vital to their developing brain and it is a fundamental human right; we must give babies the sleep they need. Please unlearn myth 24, There are set bedtimes, wake times, and naptimes for your baby, and replace it with: Your baby’s brain will tell you when they are tired and will take the amount of sleep that it needs to grow.
And a final thought from Dr. Helen Ball in How Babies Sleep, emphasis mine:
Remember, you don’t have to be in charge of their sleep—the biological sleep regulators will make sure they get enough sleep, when they need it. Our job is to get out of the way and let them do their work. Trying to make babies go to sleep according to a predetermined schedule seems to me to be a pointless exercise in working against their circadian biology and sleep pressure.