Comparing the Effects of Square, 4–7-8, and 6 Breaths-per-Minute Breathing Conditions on Heart Rate Variability, CO2 Levels, and Mood
Joshua Marchant · Inna Khazan · Mikel Cressman · Patrick Steffen
Applied Psychophysiology and Biofeedback · 2025
What the research tells us
Six-breaths-per-minute conditions increased HRV more than square or 4–7–8 breathing during practice. The experiment did not establish a meaningful mood or blood-pressure benefit; mild over-breathing occurred with the six-breath conditions.
Scope & interpretation
One session, a narrow student sample, equipment-related missingness and no longer-term outcomes limit interpretation.
Study at a glance
- POPULATION & SAMPLE
- 84 university students in a counterbalanced within-person experiment.
- EXPOSURE / INTERVENTION / SUBJECT
- Four ten-minute conditions, separated by three-minute rests; last five minutes analysed.
- OUTCOMES
- ECG-derived HRV, end-tidal carbon dioxide, blood pressure and mood.
- TIME FRAME
- One laboratory session.
Cited on this site
Editorial & review record
Record for v1.0 · Updated
Editorial responsibility: TAP Editorial Team
Editorial note
Under the editorial responsibility of the TAP Editorial Team, this publication used AI assistance for content organization and editing.
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How responsibilities and review are recorded ↗Scope of this reading note
Published PDF: protocol, results, limitations and declarations. Supplementary analyses were not reproduced.
- Study funding
- Brigham Young University.
- Competing interests
- Authors declared no financial or other conflicts of interest.
Project support
Founded and supported by Resilio.
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