This April 2025 sleep training has been circulating across parenting groups, social media, and even professional forums, but almost no one has actually read it.
🔹 It is not a study
🔹 It collected no new data, observed no babies, measured no stress or cortisol
🔹 It is a 4-page opinion letter, commenting on selected past studies, not original scientific evidence.
A Holistic Breakdown for Parents, Professionals, and Sleep Educators
By Mar De Carlo
Holistic Pregnancy & Child Sleep Coach Pioneer
Founder of the Holistic Science of Sleep Method™ and IPHI (2009)
Let’s clear this up responsibly, compassionately, and scientifically.
📌 Is It Really a New Sleep Training Study?
No.
It is not a study.
This April 2025 publication is:
A 4-page Letter
Not a study, not a trial, not original research
Contains no infants, no families, no observations
Includes no cortisol or stress testing
Offers no new scientific evidence
💡 It is an opinion letter discussing other studies, not a sleep study itself.
🧠 Why This Matters
This letter claims there is “not enough evidence that crying is harmful.”
But scientifically and ethically, we cannot then conclude that:
“No evidence of harm” = “Proven safe.”
That is not science.
That is assumption.
🔍 What Most Sleep Training Research Actually Measures:
| Commonly Measured | Rarely or Never Measured |
|---|---|
| Night waking | Cortisol levels |
| Sleep duration | Heart rate variability |
| Sleep onset time | Nervous system stress |
| Cry frequency | Attachment security |
| Parental report | Emotional regulation |
| Short-term results | Long-term outcomes |
Most studies last only days or weeks, not months or years.
Most rely on parent-reported sleep logs, not physiological assessments.
Few examine how sleep training affects long-term emotional resilience, bonding, or stress recovery.
⚠️ 3 Things Sleep Studies Almost NEVER Measure But Matter Most to Your Baby
1️⃣ Nervous System Stress Response
(Cortisol, heart rate, stress hormone activation)
Most studies measure when crying stops —
not whether stress actually returns to a calm, regulated state.
2️⃣ Emotional Regulation & Attachment Security
How safe, connected, and emotionally supported a baby feels —
not just how long they sleep.
3️⃣ Long-Term Developmental Effects
We rarely track what happens months or years later:
How do these methods impact self-regulation, bonding, emotional health, behavior, or resilience?
🧾 Even the Authors’ Own 2024 Review Admitted:
📌 “There is a lack of high-quality research in this field.”
📌 “More randomized studies are needed to avoid therapeutic misuse.”
📌 “We cannot generalize to all infants, ages, or families.”
Yet this 2025 letter is being promoted as if the science is fully settled.
That is a contradiction.
🧡 Why This Matters for Parents and Professionals
Decisions made in the name of science
should actually be based on science —
not assumptions, headlines, or convenience.
Parents deserve more than cry timers, sleep charts, and surface-level behavior tracking.
They deserve:
✨ Respect for emotional development
✨ Understanding of stress biology
✨ Attachment-based guidance
✨ Nervous-system-safe strategies
✨ Customized support — not standardized scripts
🌙 Why Holistic Sleep Support Is the Evolution Beyond Sleep Training
I don’t shame sleep training.
I don’t shame exhausted parents.
I don’t shame professionals who still use it.
💛 I simply recognize that traditional sleep training was built on an older behavioral model, one that focused on reducing crying and promoting “sleep independence,” rather than understanding stress, co-regulation, or the developing nervous system.
Today, we know more.
We understand:
🧠 The nervous system
🫶 The role of co-regulation
💗 How early experiences shape emotional resilience and relational safety
A holistic approach honors sleep as a physiological, emotional, relational, and developmental process.
Not just a behavioral one.
In holistic sleep support, we don’t just train sleep.
We nurture regulation.
We build trust.
We protect emotional development.
We honor connection and rest.
✨ Sleep training was the first chapter.
Holistic sleep is the evolution.
💛 Share the Truth. Support Another Parent.
Sleep science can be confusing, incomplete, or easily misinterpreted.
Parents deserve clarity, not fear-based messaging or oversimplified solutions.
📎 Save this
📩 Share this with a parent, educator, or professional
Because awareness leads to informed decisions.
And informed decisions protect emotional health, not just sleep.
Explore our sleep certification programs:
Holistic Pregnancy & Child Sleep Consultant Certification
Holistic Children & Teen Sleep Coach Certification
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