Box breathing, four counts in, four hold, four out, four hold, is taught to soldiers and police as "tactical breathing." The book teaches it too, as a steadying pattern for when there is time. The evidence behind it is thinner than its reputation, and the one head-to-head test is instructive.
Thirty healthy adults did a demanding Stroop task under time pressure and rising white noise, using either box breathing or a plain prolonged exhale to manage the stress. On how stressed people felt, the techniques tied. On the body's measures, box breathing produced slightly lower arousal. On the task itself, the prolonged-exhale group performed better. The authors' reading: box breathing may suit passive waiting, while the long exhale is the better choice when you have to act. That matches the booth, where you cannot hold your breath for four counts in the middle of a line.
It is one lab study of thirty people, so treat it as a hint rather than a ruling. The book's box breathing page carries the same caveat, and the Quick Chooser already sends the active, mid-task moments to the exhale.
The studies
Röttger S, Theobald DA, Abendroth J, Jacobsen T. The effectiveness of combat tactical breathing as compared with prolonged exhalation. Applied Psychophysiology and Biofeedback 46(1), 2021, 19–28. Read the abstract
- Sample
- 30
- Design
- Lab comparison during a Stroop task under time pressure and noise.
- Found
- No difference in subjective stress; lower physiological arousal with tactical breathing; better task performance with prolonged exhalation.
- Limits
- Healthy volunteers, single session, laboratory stressor rather than a real one.
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.