The science of slow breathing
Breathing includes evidence-informed techniques, with cited references inside the app. These pages explain how to practice them and summarize what the cited evidence shows, including its limits.
All techniques
Box breathing (4-4-4-4)Four equal phases — inhale, hold, exhale, hold.Coherent breathingEqual inhale and exhale, no holds, around five to six breaths per minute — the cadence where heart and breath fall into step.4-7-8 breathingInhale for 4, hold for 7, exhale for 8.The physiological sighTwo quick inhales, one long exhale.
What the research actually shows
- Across many studies, slow breathing (under ~10 breaths/min) is associated with higher heart-rate variability, relaxation and reduced arousal, though individual responses vary (Zaccaro 2018; Russo 2017).
- For many people, a resonance range lies around 5.5–6 breaths per minute, where breath and baroreflex can reinforce each other — the basis of HRV biofeedback (Lin 2014; Lehrer & Gevirtz 2014).
- In a small study of 30 participants, a longer exhale relative to the inhale was associated with greater reported relaxation; higher high-frequency HRV appeared only during slow breathing (Van Diest 2014).
- A remote, open-label randomized study assigned 108 participants to one of four groups; each protocol called for five minutes of daily practice for 28 days. Cyclic sighing increased positive affect more than mindfulness and reduced resting respiratory rate; it did not test a three-sigh demo (Balban 2023).
References
- Zaccaro et al., 2018 — Systematic review of slow breathing (Frontiers in Human Neuroscience)
- Lin et al., 2014 — Study of paced breathing in healthy adults (International Journal of Psychophysiology)
- Van Diest et al., 2014 — Study of breathing patterns and relaxation (Applied Psychophysiology and Biofeedback)
- Lehrer & Gevirtz, 2014 — Review of HRV biofeedback mechanisms (Frontiers in Psychology)
- Critchley et al., 2015 — Study of slow breathing and brain activity (PLOS ONE)
- Russo et al., 2017 — Review of slow-breathing physiology (Breathe)
- Balban et al., 2023 — Randomized study of daily breathing practices (Cell Reports Medicine)
- Li et al., 2016 — Basic research on sighing circuits (Nature)
Disclaimer: This information is educational and not medical advice. If you have cardiopulmonary or other medical conditions, consult a healthcare professional before changing your breathing practices.
