The book's Chapter 11 is careful about sleep: breathing can help you stop fighting the bed, and the evidence-based treatment for chronic insomnia is cognitive behavioral therapy for insomnia (CBT-I), which the book points you toward. The breathing studies are small and interesting.
In a Taiwanese lab, fourteen self-reported insomniacs and fourteen good sleepers had their heart-rate variability measured during slow paced breathing (six breaths a minute) and a faster forced rate. The insomniacs showed depressed vagal activity, which rose during slow breathing. When they practiced twenty minutes of slow paced breathing before sleep, polysomnography showed shorter time to fall asleep, fewer awakenings, less time awake during the night, and higher sleep efficiency. A review from the same era lays out the proposed mechanism (vagal activation and quieting of the arousal system) and calls breathing an adjunct to, not a replacement for, insomnia treatment.
Fourteen people, one lab. The practical version is the book's in-bed sequence, and the Three A.M. room is built on the same idea: the goal is to stop rehearsing panic, not to force sleep.
The studies
Tsai HJ, Kuo TBJ, Lee GS, Yang CCH. Efficacy of paced breathing for insomnia: enhances vagal activity and improves sleep quality. Psychophysiology 52(3), 2015, 388–396. Read the abstract
- Sample
- 28 (14 insomniacs, 14 good sleepers)
- Design
- Lab HRV study plus polysomnography after twenty minutes of slow paced breathing before sleep.
- Found
- Insomniacs' vagal activity rose during slow breathing; sleep onset latency, awakenings and wake time fell and sleep efficiency rose after pre-sleep practice.
- Limits
- Small; self-reported insomnia; short-term outcomes.
Jerath R, Beveridge C, Barnes VA. Self-regulation of breathing as an adjunctive treatment of insomnia. Frontiers in Psychiatry 9, 2018, 780. Read the abstract
- Sample
- Review
- Design
- Narrative review of mechanisms and evidence.
- Found
- Proposes vagal activation and reduced arousal as the pathway; positions breathing as an adjunct to standard insomnia care.
- Limits
- Narrative, not systematic.
Where this lands in the book
Techniques
Rooms
Two rules, no exceptions
Never practice any technique on this site while you are driving, operating machinery, or doing anything that needs your full attention. The slow ones can make you drowsy, faster than you’d expect. And never practice a breath-hold, bellows breath, or any vigorous breathing in or near water. Read Before you begin for the doctor’s list and the rest.
Verdict scale: Science means trials or meta-analyses with consistent findings; Promising means real trials that are small, few, or unreplicated; Mixed means the studies point both ways; Mechanism means it shows how something works in the body, not that it helps in life. Checked against the published abstracts in October 2026. Not medical advice.