The book's booth-and-control-room chapter claims that steadying the breath leaves more attention for the take. The lab versions of that claim are modest and consistent.
In the largest, 139 undergraduates were randomized to a single short slow-paced breathing session or an active mind-wandering control, then did a working-memory task. Working memory improved in the breathing group; mood improved and stress fell relative to control, though both drifted back after the demanding task. In a two-part Belgian study, thirty people's heart-rate variability rose with either a symmetric or a long-exhale pattern but not with a neutral film; then 56 students did two minutes of the long-exhale pattern or waited, before a thirty-minute business decision task. Controls got more stressed; the breathing group did not, and answered more questions correctly. In a Chinese trial, forty adults did twenty sessions of diaphragmatic breathing over eight weeks at about four breaths a minute with feedback, or nothing; the breathing group improved on sustained attention and negative affect and had lower cortisol afterward.
These are healthy students and office workers, single sessions in two of three, and the control groups were passive in two of three. Still, "two minutes of long exhales before a hard meeting" now has a trial behind it, which is more than most advice can say. The book's Soundcheck is the sixty-second version.
The studies
Pilcher, Byrne, Weiskittel, et al. Brief slow-paced breathing improves working memory, mood, and stress in college students. Anxiety, Stress & Coping 38(5), 2025, 528–543. Read the abstract
- Sample
- 139
- Design
- Randomized to a one-time slow-paced breathing session or an active mind-wandering control, with a working-memory task.
- Found
- Working memory improved in the breathing group; mood rose and stress fell relative to control after the manipulation, then both conditions worsened after the task.
- Limits
- Undergraduates; single session; effects partly transient.
De Couck M, Caers R, Musch L, Fliegauf J, Giangreco A, Gidron Y. How breathing can help you make better decisions: two studies on the effects of breathing patterns on heart rate variability and decision-making in business cases. International Journal of Psychophysiology 139, 2019, 1–9. Read the abstract
- Sample
- 30 and 56
- Design
- Study 1: HRV during two breathing patterns versus a neutral film. Study 2: two minutes of long-exhale breathing versus waiting, before a thirty-minute decision task.
- Found
- Both patterns raised HRV; the film did not. The breathing group avoided the rise in stress seen in controls and answered more questions correctly.
- Limits
- Students; short tasks; self-reported stress.
Ma X, Yue ZQ, Gong ZQ, et al. The effect of diaphragmatic breathing on attention, negative affect and stress in healthy adults. Frontiers in Psychology 8, 2017, 874. Read the abstract
- Sample
- 40
- Design
- Randomized to twenty feedback-guided sessions over eight weeks at about four breaths a minute, or no treatment.
- Found
- Sustained attention and affect improved and cortisol fell in the breathing group; no change in controls.
- Limits
- No active control; healthy adults; one site.
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.