Sleep Training Methods and Research About Sleep Training
The beautiful thing about sleep training methods is that they’re not written in stone. Meaning, you can modify/tweak/whatever method so that it feels right to you! There aren’t any hard and fast rules when it comes to sleep training because every child is different.
And while we’re here talking about sleep training methods, we might as well look at the evidence and research about the safety of sleep training too!
So in this blog about sleep training methods and research, we will cover:
What sleep training is/isn’t (what if you want to keep feeding at night?)
Popular methods you may have heard of (or not)
Sleep training without crying?
Appropriate age for sleep training
When sleep training “isn’t working”
Should you sleep train during a regression or teething?
How long should sleep training take?
Research about sleep training (specifically, not stuff that’s spun to look like sleep training)
What sleep training is/isn’t (what if you want to keep feeding at night?)
Sleep training gets a bad reputation. I recently saw an “anti-sleep training account” define sleep training as the following (or a way to know if someone “sleep trains”):
-offering better sleep in X amount of days
-says “bad habits” or says your child's needs are inconveniences
-forces night feedings or extreme feeding changes
-doesn’t take into account biologically normal infant sleep
-doesn’t account for temperament
-doesn’t address root causes of sleep disturbances
So… yeah, it’s not any of those things.
No one can say that for sure, your child is going to sleep better in a specific number of days. Kids aren’t robots and no one knows how exactly your child will respond to changes around sleep, how gradually parents are making changes, etc. There are an infinite number of ways to reach your goals and without specifics, we can’t give you a timeline to hold your child to.
“Bad” habits are subjective and honestly, everyone has habits around sleep. Whatever those habits are, we want them to feel right and sustainable for you. Which is why sleep is so different for every family! Because everyone has different thresholds, parenting styles, goals, etc.
Sleep training is not synonymous with night weaning or weaning from breastfeeding. Generally night weaning will require some sleep training, but you can continue feeding however many times a night you want while still improving sleep. Formula/bottle fed and breastfed babies all struggle equally, not one more than the other with sleep.
Biologically normal infant sleep means that we cannot physically change their wakings. Night wakings will continue to happen because they’re protective. You cannot train them away. But you can ensure they are able to return to sleep without your assistance with sleep training as long as something they need/cannot do for themselves isn’t preventing them from going back to sleep.
Babies all have different temperaments which means every baby will respond differently to the different methods you have to choose out there. Some will be more sensitive and easily overstimulated by your assistance while chill babies could take your presence or leave it! Temperament is absolutely a factor a sleep consultant should consider when working with families.
If a sleep consultant isn’t trained in knowing what red flags to look for (open mouth breathing, snoring, tongue/lip ties, etc etc etc), then work with someone else! If sleep disturbances are unresolved despite doing all the “right” things, then something should be investigated. They should be asking you questions to get to the root cause of sleep troubles.
Sleep training is also not:
A way to ignore your child for 12 hours
Abuse or neglectful
Sleep training is a behavioral modification to change sleep habits (and generally refers to working on falling asleep independently/without parental assistance).
Popular methods you may have heard of (or not)
It’s very easy to google sleep training methods and find various ones that you may want to use (or not!)
They fall into these main “camps”:
Low tears/gradual
Check and console
Camping out
Extinction
“Low tears” or gradual methods refer to options like:
The no cry sleep solution
Pantley pull out
Pick up put down
Shush/pat
Dr. Jay Gordon’s weaning method
Check and console:
Sleep wave
Ferber
“I’ll be back”
The kissing game
Bedtime pass
Camping out:
The chair method
In room intervals
Extinction:
CIO (cry it out)
I feel like you can google all the details on these methods, combine methods, whatever you want to do to modify it to make it work for you and your family!
And as always, I have plenty of options for families if they feel like these just still aren’t a great fit– many methods that I have written/combined/tweaked myself!
Sleep training without crying?
The million dollar question- how do you sleep train without any tears?!
The answer: no cry sleep training doesn’t really exist. You cannot control your child’s response to changes around their sleep. The only thing that you can change is your response to their crying!
Here’s a blog with more details.
Appropriate age for sleep training
If we wanna use some fancy terms, sleep “shaping” can happen from day one! Meaning, we can be mindful of: their awake periods so they don’t get overtired, their sleep environment, routines around sleep, and you can start putting them down awake and being curious about not having to help them to sleep every time.
You certainly don’t have to, and with newborns, they end up having a lot of opportunities to try this because they sleep so much! If you put them down, and they cry, you can settle them without putting them all the way to sleep, or you can if you want to. There’s no right or wrong here!
If you want to use separation based methods, the general consensus is after 4 months when object permanence is more developed!
When sleep training “isn’t working”
There are a lot of reasons it can seem like sleep training isn’t “working!”
Here are some ideas for considering if sleep training is working or not:
They’re falling asleep within 5-20 mins for naps and bedtime
They’re consolidating their night time sleep stretches
They’re consolidating their naps
It doesn’t mean it’s not working if they still wake up at night or if they cry whenever you put them down! Those aren’t markers at all for success.
If you feel like they’re struggling with falling asleep and staying asleep despite implementing a sleep training method, then evaluate the timing of naps and bedtime, how much daytime sleep they’re getting, and if the method itself isn’t a good fit! Try to give it a week before changing too many things.
Should you sleep train during a regression or teething?
Going through a sleep regression or teething isn’t a reason to not sleep train. Often, sleep training through a regression is how you get through it! A consistent response leads predictability and calm to their chaos whenever it feels like their world is changing a lot.
Same with teething– unless they’re running a high fever, vomiting or have diarrhea, there aren’t a ton of other reasons to not sleep train or to pause what you’re doing.
Here’s another blog about teething!
How long should sleep training take?
This will depend entirely on the method that you’re using. Methods like ferber and CIO work in a shorter amount of time than methods like the chair or PUPD. This is because you’re usually making bigger changes faster as opposed to smaller changes with more intervention with more hands on methods. That just means it’ll take you longer to reach your end goal.
The only reason that matters is so that you have reasonable expectations!
Research about sleep training (specifically, not stuff that’s spun to look like sleep training)
We can say there is no evidence of harm through the years of research that’s been done on sleep training, but can we say there is evidence of NO harm?
No, actually, and we can’t say that about ANYTHING. There is no standard which we can ever say ANYTHING could never be harmful for one child or another in particular situations but that doesn't keep us from making recommendations based on the evidence. There’s basically no way to gather evidence of no harm, 100%.
We can look at the evidence we do have and say based on everything we’ve gathered, there are no detrimental effects. No evidence of harm.
It’s double speak to say well, all the evidence says no harm but MAYBE THERE IS. (I guess you could if you want to stress parents out all the time). We could say this about car seats, baby led weaning.. Anything.
Now, I never try to bust sleep training myths to convince people to sleep train. That would never be the point of any evidence based information.
The information is there to say if this is your choice, you’re justified. If it isn’t, you’re also justified.
(But if you want to see me debunk some articles… here you go! annnnd this one too.)
Here’s some research articles you can read through at your leisure if that’s your kinda thing 🤓
“Infant and parental factors interact to influence the development of self-soothing.”
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1201415/
“..infants who were consistently put into the crib awake were more likely to be self-soothers than infants who were consistently put into the crib asleep. Infants who required parental assistance to fall asleep at the beginning of each night were more likely to require parental assistance upon awakening in the middle of the night.”
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1201414/#R32
“Sleep training improves infant sleep problems, with about 1 in 4 to 1 in 10 benefiting compared with no sleep training, with no adverse effects reported after 5 years. Maternal mood scales also statistically significantly improved; patients with the lowest baseline depression scores benefited the most.”
“Behavioral sleep techniques have no marked long-lasting effects (positive or negative). Parents and health professionals can confidently use these techniques to reduce the short- to medium-term burden of infant sleep problems and maternal depression.”
This is one of the most consistent findings in infant sleep research. Babies who fall to sleep on their own at the beginning of the night tend to sleep better during the night, whereas more active soothing from a parent at bedtime is associated with more disrupted sleep during the night. All babies wake several times during the night, but those that know how to go to sleep on their own are more likely to be able to comfortably resettle in the night without crying for help from a caregiver. This has been shown in studies from around the world, including the United States and Canada, Thailand, the U.K., and in a cross-cultural survey of more than 29,000 babies from 17 different countries.
Note: Just be aware that actigraphy itself isn’t a super reliable way to measure sleep! It’s getting better, but those who quote articles using actigraphy have to know that it isn’t the best.
This article: sleep training improves infant sleep with no adverse effects.
This article provides links to several studies on sleep training. These studies show that it is effective and that the main predictor of children being able to sleep a 6 hour stretch was removing parental presence at bedtime. Claims of negative effects due to any crying during sleep training have not been able to be replicated by studies. The one study most often cited is based on long term abuse and neglect, not on a healthy child in a happy, responsive home being allowed to cry for a controlled amount of time while a parent responds during a short term period. There have been many studies validating short and long term negative effects of sleep deprivation for both baby and parents. Follow up studies on children at six years of age show no difference in emotional issues, sleep issues or attachment issues between children who were sleep trained or not sleep trained.
This study discusses how Danish babies tend to cry much less overall and have less incidence of colic, despite unusually high breastfeeding rates in the country, which is typically correlated with more crying. The conclusion as to why? According to this article which discusses the study’s conclusions in plain language, “Danish parents are regularly credited with having a healthier, more relaxed approach to parenting, preferring to give their children what the book The Danish Way of Parenting calls “proximal development” – or the space to grow and explore. They do not, we are told, hover like helicopters over the cribs of their infants, literally or metaphorically – instead opting to put their offspring to sleep in prams outside, where they believe the air is cleaner.” We can deduce that because Danish parents don’t necessarily scoop the baby up at every fuss and noise, they learn to settle themselves earlier and more easily than most babies.
“Sleep consolidation evolves rapidly in early childhood. Parental behaviors at bedtime and in response to a nocturnal awakening are highly associated with the child’s sleep consolidation. The effects are probably bidirectional and probably create a long-term problem. Early interventions could possibly break the cycle.” https://jamanetwork.com/journals/jamapediatrics/fullarticle/485959
The truth is that nature – a baby’s unique genetic make-up – accounts for somewhere between about a quarter and a half of the variation in infant nighttime sleep patterns
One of the ways that we influence our babies’ sleep patterns is through our attitudes and beliefs about infant sleep. These were measured in an Israeli study that surveyed 85 women beginning in pregnancy and when their babies were 1, 6, and 12 months old.
The study also evaluated the babies’ sleep, allowing the researchers to see correlations between parenting philosophies and infant sleep patterns.
All of these mothers were caring and responsive, but their beliefs about infant sleep fell along a spectrum. Beginning in pregnancy, some mothers tended to interpret a waking baby as a distressed baby who always needed help from a caregiver. These mothers ended up taking a more active role in soothing their babies to sleep, and their babies also ended up waking more during the night in infancy.
Other pregnant mothers in the study believed that babies were capable of sleeping and that they didn’t always need help from a parent to sleep. These mothers were more likely to end up letting their babies settle on their own, and their babies ended up waking less during the night. A follow-up study found that mothers’ sleep philosophies at 12 months also impacted how their children slept at four years of age.
These studies show that if we believe that our babies can sleep without our help, then they’re more likely to do so.
In a fascinating study published in 2015, 101 London infants were video-recorded through one night at 5 weeks and 3 months of age. All of the infants woke during the night, but at both ages, about one quarter of the babies resettled during the night without the help of their parents. Most didn’t cry upon waking, and the rest fussed or cried for an average of about one minute before going back to sleep. The published study included a sweet 3-minute video example of a 3-month-old baby resettling during the night. An earlier study found that about half of 3-month-olds resettled in the middle of the night without help from a parent.
Although not all of the babies in these studies were observed to resettle themselves, it shows that the possibility is there, and more babies might resettle if given a few minutes to try.
Another study showed that when parents gave their 3-month-olds a few minutes to try to go back to sleep on their own after a night waking, they were more likely to be sleeping through the night at 12 months of age.
Between the 5-week and 3-month measurements, the London study also found that there was a clear developmental progression in lengthening sleep periods.
By 3 months of age, 68% of babies were sleeping (or self-settling) for at least a 5-hour stretch during the night, and this was just as likely with exclusively breastfed babies as with formula-fed babies. There was also a big increase in the number of infants that sucked on their fingers or hands during sleep (from 18% at 5 weeks to 62% at 3 months). These babies were finding that a little comfort was as close as their own hands.
What about attachment? What about cortisol? I got ya.
Here’s why we can’t use the Middlemiss study about cortisol to prove anything about sleep training:
1) Cortisol levels in both mom & baby were already elevated on the first day of the study. Before the bedtime routine or any crying even began.
This could be because: they were in a clinical setting
The babies were handled by unfamiliar people instead of their parents
Mom’s anxiety about the separation
Maybe the most important: cortisol is a primary hormone produced by the body in reference to circadian rhythms which means there are natural ebbs and flows to cortisol throughout the night (and if the child is already overtired-- it will peak at bedtime).
It’s impossible to responsibly conclude that the cortisol was present only because of any subsequent crying that occurred. And to me, the fact that the children already had elevated cortisol levels before any sleep training was initiated indicates that those levels were not created by the process of sleep training. It could also be safe to assume that they were not sleeping well to begin with and had the overtired/stressed affects already present.
2) The study did not show any significant increase in levels between pre- and post-bedtime. Levels were also not measured at any time during the night; they were only measured right before the babies were put down, and shortly after they fell asleep. There were no measurements taken throughout the night.
3) The levels were also only measured on the first and third days of the five-day program. That’s pretty weird! They just stopped measuring the data a little more than halfway through the study. To draw any reasonable conclusions, there should have at least been measurement on the very last day of the study; drawing conclusions based on partial data seems irresponsible from a research perspective.
4) A final, and very important, issue with this study is that there was no control group. There was no group of babies undergoing sleep training in their home environment; there was no group of babies NOT undergoing any sleep training. A control group is an essential part of any experiment or study; my findings are as good as useless if I have nothing to pair it against.
Here’s what we do know about cortisol:
Cortisol can be measured in saliva, so it can be sampled in a non-invasive manner without causing additional stress, even while a baby is sleeping. Without unusual levels of stress, cortisol has a natural circadian rhythm, being 300-400% higher in the early morning than at its lowest point around midnight. This pattern does not develop until infants are several months old, and it is what helps them to sleep at night and be awake during the day.
A surge in cortisol outside of this normal pattern can indicate that a baby is stressed. However, it is simplistic to assume that any rise in cortisol is dangerous, given its importance to daily function. Cortisol is not a problem unless it is elevated for extended periods of time as in the case of chronic stress.
In one study, newborns were given a mock exam two days in a row. On the first day, the babies had increased cortisol and cried during the exam. However, when the exam was repeated on the second day, the babies did not show an increase in cortisol, though they still cried almost as much as they had on the first day. Somewhere in their brains, they recognized that this experience had happened before. This study illustrates a positive stress response. The babies were initially stressed by the exam, but they were able to recover and learn from the experience so that they could cope with it effectively the next day. >>It also demonstrates the important point that crying is not always accompanied by increased cortisol.<<
So how stressful would sleep training be if a child is in their own room with reassurance from a parent? I’m really not convinced that it could be as bad as people say (obviously). If I had to guess, I would predict that age-appropriate sleep training in a familiar and supportive environment would cause a small increase in cortisol for a few nights, but not chronically.
There are studies that have looked at cortisol levels in babies that were separated from their mothers briefly. 9 month old babies were left alone for 30 minutes with a stranger in a lab which caused a 20-40% increase in cortisol. That’s minor considering it fluctuates 10x that much on a daily basis. Other studies show that by 12-18 months, maternal separation does not increase cortisol.
Let’s consider a stressful situation that’s actually comparative to sleep training: starting daycare! This involves a big change in their routine and prolonged separation from an attachment figure. This can cause an increase in cortisol EVEN IF mom stays for the first two weeks.
Okay, so what about attachment?!?!
A secure attachment has at least three functions:
Provides your child a sense of safety and security
Helps your child regulate their emotions
Offers your child a secure base from which to explore
Attachment is not based on things you do (breastfeeding, baby wearing, bedsharing, etc). The principles are fine if that’s what’s working for you, but they’re not essential nor predictive of a secure attachment.
The interaction we have with our child is how the attachment is formed. “Mechanical and insensitive breastfeeding could contribute to an insecure attachment whereas a warm, sensitive and interactive bottle-feeding could help create a secure attachment. It isn’t the method, it’s the quality of interaction.”
What matters for attachment is the caregiver’s attunement. Are they stressed or calm? Checked out or engaged? Are they reading the baby’s signals?
Attachment parenting advises emotional responsiveness, and this practice aligns best with scientific attachment theory. Babies grow best when their feelings are taken seriously. But well-meaning parents can overdo it, believing they need to meet the child’s every request, which can be exhausting and counterproductive. In contrast, research on secure attachments shows that, in the flow of everyday life, misattunements happen about 70 percent of the time! (This means we only have to meet the call of our child THIRTY percent of the time!!! that's a bare minimum for secure attachment which I can only assume that those in healthy relationships are well above that).
What is important, researchers say, is that "the baby develops a generalized trust that their caregiver will respond and meet their needs, or that when mismatches occur, the caregiver will repair them. This flow of attunements, mismatches, and repairs offers the optimal amount of connection and stress for a baby to develop both confidence and coping skills."
And self soothing? Is that a myth too!? Nah, I got a blog for that too.
Whew— if you made it this far congrats ⭐️🏆. If not, the research and information will be here whenever you need it!
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