The Research: Culture Apothecary Sleep Training Episode
Being a guest on Culture Apothecary was an incredible honor, and I'm so grateful for the opportunity to speak with Alex and her audience about pediatric sleep support.
I know that podcasts can make it challenging to cite sources or provide detailed research in real time. I created this post to offer supporting evidence for the topics we discussed—and to expand on a few areas we didn't have time to cover. Below, you'll find research citations, studies, and additional context to help you explore these topics further.
IN THIS POST:
How Sleep Works
What Sleep Training is (and isn’t)
Common misconceptions and evidence based responses
Attachment
Cortisol and Stress
Shutdown Syndrome / Learned Helplessness
Biologically normal infant and toddler sleep
Holistic Benefits of Evidence-Based Sleep Support
Miscellaneous Claim and Response: Babies who are sleep trained don’t sleep more than non-sleep trained babies.
Practical Takeaways for families
Listen to the full episode HERE.
1. How Sleep Works:
We all sleep in cycles. When we transition through one sleep cycle to the next, we all experience a little mini awakening. These are normal and happen several times a night (5-7+ times). Adults and children who know how to fall asleep unassisted, breeze through these little mini wakings and barely notice.
If a baby or toddler is used dependent on someone or something external they will likely have a hard time during those little mini awakenings. All they know is that they fell asleep one way and now things are different. It would be like you falling asleep in your bed and waking up in the bathtub. That would be pretty shocking and you would definitely wake all the way up instead of rolling over and going right back to sleep (more on how sleep works HERE).
2. What Sleep Training Is (and Isn’t):
Sleep training is:
An umbrella term for a variety of interventions used to help your baby confidently fall asleep and transition through sleep cycles unassisted (without external props). It is a safe and reliable option for working through sleep habits if families choose to use it.
To date, there is no published, evidence-based research showing that sleep training causes harm. In fact, the bulk of pediatric sleep research supports its safety and effectiveness. My goal is to offer accurate, evidence-based information so families can make an informed decision.
A spectrum: there are many different ways to sleep train and it should not be a, “one size fits all” approach.
Focuses on habit changing.
Evidence-based sleep support aligns with sleep science: it recognizes that newborns have different sleep patterns, that all infants experience biologically normal wakings during the night, and agrees with the value and importance of breastfeeding, bonding, and physical closeness. A well-rounded approach to sleep support for infants and children should look at a combination of sleep science, child development, general evidence-based research on pediatric sleep health, and the research surrounding sleep training. Sleep training is part of a holistic approach that includes nutrition, circadian rhythm support, consistent timing and routines, and responsive caregiving.
Concept: Scaffolding
Sleep training provides support while children practice independence, like a Montessori “help me do it myself” principle.
Examples: consistent timing and routines, consistent and predictable responses, giving space to practice falling asleep independently.
Sleep training is not:
Abandoning a child.
Ignoring hunger, illness, or emotional needs.
A method to “train out” biologically normal wakings or “teach” children how to sleep (sleep is a biological function).
Notable Evidence Based Research on Sleep Training:
Mindell et al. (2006). Behavioral treatment of bedtime problems and night wakings in infants and young children. This is a comprehensive review of sleep training research. It analyzed 52 studies.
Price et al. (2012). Five-year follow-up of harms and benefits of behavioral infant sleep intervention: Randomized trial.
Hiscock et al. (2008). Long-term mother and child mental health effects of a population-based infant sleep intervention: Cluster-randomized, controlled trial.
Gradisar et al. (2016). Behavioral interventions for infant sleep problems: A randomized controlled trial.
The above studies represent a sample of widely cited, high-quality research supporting sleep training. While individual studies all have methodological limitations (this is true of all research), the body of sleep training research demonstrates consistent findings across multiple high-quality randomized controlled trials, systematic reviews, and meta-analyses, providing families with a reliable evidence base for informed decision-making about behavioral sleep interventions. The convergence of evidence across different study designs and populations strengthens confidence in the safety and efficacy of behavioral sleep interventions.
3. Common Misconceptions and Evidence-Based Responses
A. Attachment and Parent-Child Bonding
Concern: Sleep training harms attachment.
Evidence-based response:
A lot of the concern around sleep training comes from theoretical interpretations of attachment and stress — not from studies that actually measure attachment outcomes after sleep training.
Attachment is built over thousands of interactions.
Secure attachment comes from a pattern of loving, responsive caregiving, not easily broken by brief interventions like sleep training.
Attachment parenting (a parenting philosophy) and attachment science are not the same.
Research shows no harm to attachment from evidence-based sleep training:
Price et al., 2012 – 5-year follow-up; no differences in attachment.
Gradisar et al., 2016 – randomized trial; no negative impact on emotional health or attachment.
Mindell et al., 2006 – 52-study review; no attachment concerns found.
Madigan et al., 2024 – attachment is measurable and resilient.
More about attachment theory.
B. Cortisol and Stress
Concern: Sleep training causes toxic stress or brain damage.
Evidence-based response:
Cortisol is not inherently bad; it’s a necessary hormone that fluctuates throughout the day.
Types of stress:
Positive stress – brief, normal elevations (shots, new babysitter).
Tolerable stress – longer, buffered by caregivers (injury, loss).
Toxic stress – prolonged, unbuffered, leads to measurable harm (abuse, neglect).
Evidence-based sleep training involves brief, intermittent crying — it does not trigger toxic stress. The clinical definition of “prolonged crying” does not align with the brief, intermittent crying seen in sleep training.
Gradisar et al., 2016 – salivary cortisol showed small-to-moderate decreases in intervention groups, directly contradicting “shutdown syndrome” concerns.
Middlemiss et al., 2012 – widely misinterpreted; methodological limitations make it inconclusive. The study involved only 25 mother-infant pairs, lacked a control group, and collected cortisol data from less than half of the participants. Infants were placed in cribs by unfamiliar caregivers in a lab setting while their mothers waited outside—conditions likely to influence stress levels regardless of the intervention. The statistical analysis was weak and data were only collected on nights one and three, offering no insight into longer-term outcomes. The study was not designed to assess the safety of sleep training.
Dr. William Sears is the founder of Attachment Parenting; his book and article “The Effects of Excessive Crying” raise concerns about attachment, brain damage, and shutdown syndrome. Dr. Sears’ references are not sleep or sleep training specific. Most are theoretical review papers (the ones that are research studies aren’t relevant). See the breakdown of his resources HERE. At least two researchers he cited have stated their work was misrepresented.
Dr. Narvaez’s The Dangers of Crying It Out is a narrative opinion article, originally published in the Moral Landscapes blog on Psychology Today on December 11, 2011. The article argues against sleep training from an attachment perspective. It interprets selected research through a theoretical and moral framework; it does not present original empirical data. The references are not sleep or sleep training specific (see breakdown HERE). Most are theoretical review papers (the ones that are research studies aren’t relevant).
C. Shutdown Syndrome / Learned Helplessness
Concern: Babies stop signaling or withdraw emotionally (learned helplessness).
Evidence-based response:
Not evidence-based; not a recognized medical diagnosis.
Often based on extreme neglect studies and applied to sleep training (e.g., Romanian orphanages) — not comparable to loving, responsive homes. More research here, here, here, and here.
Sleep-trained babies continue to signal.
Gradisar et al., 2016 – salivary cortisol decreased; emotional signaling remained intact.
D. Biologically Normal Infant Sleep
Concern: Sleep training goes against biologically normal baby and toddler sleep
Nighttime awakenings are normal and necessary for all infants.
Sleep training does not suppress natural awakenings.
Focus is on habit changes around sleep that support independent transitions between sleep cycles.
Aligns with sleep science, child development, and evidence-based sleep health.
4. Holistic Benefits of Evidence-Based Sleep Support
Improved parent mental health and confidence.
Lower maternal depression risk (Bayer et al., 2007; Hiscock et al., 2006 (additional information HERE, HERE, HERE, HERE).
The influence parent mental health can play short-term during infancy and long-term into childhood: HERE, HERE, HERE.
Better marital satisfaction (Gordon et al., 2013; Medina et al., 2009).
Physical benefits: immune system, growth, and lower obesity risk (Zhou et al., 2015).
Supports child cognitive, language, and motor development and memory consolidation.
Impaired function: A Harvard study found that sleeping fewer than 5 hours per night for one week can impair functioning as much as being legally intoxicated.
5. Miscellaneous:
Claim: Babies who are sleep trained don’t sleep more than non-sleep trained babies. This idea comes from a study done by Stremler et al. (2013), however this was not a traditional sleep training study. The mothers received preventative information including nurse-led sessions, booklets, and follow-up phone calls focused on sleep information and strategies to promote maternal and infant sleep. Nowhere are we told they received any information on traditional sleep training strategies. The Stremler studies emphasized sleep hygiene, sleep strategies, and general sleep promotion techniques delivered in the early postpartum period. A comprehensive review of over 50 sleep training studies done by Mindell et al. (2006), showed that 94% of studies reported behavioral interventions were effective, with over 80% of treated children showing clinically significant improvement that was maintained for 3-6 months. To clarify, “3-6 months” does not mean the positive results went away after that time, it was simply the typical follow-up period in most of the studies (the study notes a need for additional studies to show longer-term efficacy).
6. Practical Takeaways for Families
Sleep training is optional but safe and evidence-supported.
Helps families establish predictable routines, flexibility, and overall well-being.
Should always be paired with responsive caregiving.
