The science of slow breathing
Every technique in Breathing is built on published research, cited inside the app. These pages explain how each one works, how to practice it, and what the evidence actually shows — no more, no less.
All techniques
Box breathing (4-4-4-4)Four equal phases — inhale, hold, exhale, hold — used by everyone from clinicians to special forces.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 — the reset your body already performs spontaneously.
What the research actually shows
- Slow breathing (under ~10 breaths/min) reliably increases heart-rate variability and is associated with relaxation and reduced arousal across dozens of studies (Zaccaro 2018; Russo 2017).
- Around 5.5–6 breaths per minute the cardiovascular system reaches a “resonance” where breath and baroreflex reinforce each other — the basis of HRV biofeedback (Lin 2014; Lehrer & Gevirtz 2014).
- Making the exhale longer than the inhale shifts the balance further toward the parasympathetic side (Van Diest 2014).
- In a randomized trial, five minutes of daily breathwork — cyclic sighing in particular — improved mood and lowered resting respiratory rate more than mindfulness meditation (Balban 2023).
References
- Zaccaro et al., 2018 — How breath-control can change your life: a systematic review on psycho-physiological correlates of slow breathing (Frontiers in Human Neuroscience)
- Lin et al., 2014 — Breathing at 5.5 breaths per minute with equal inhalation-to-exhalation ratio increases heart rate variability (Int J Psychophysiol)
- Van Diest et al., 2014 — Inhalation/exhalation ratio modulates the effect of slow breathing on heart rate variability and relaxation (Appl Psychophysiol Biofeedback)
- Lehrer & Gevirtz, 2014 — Heart rate variability biofeedback: how and why does it work? (Frontiers in Psychology)
- Critchley et al., 2015 — Slow breathing and hypoxic challenge: cardiorespiratory consequences and their central neural substrates (PLoS ONE)
- Russo et al., 2017 — The physiological effects of slow breathing in the healthy human (Breathe)
- Balban et al., 2023 — Brief structured respiration practices enhance mood and reduce physiological arousal (Cell Reports Medicine)
- Li et al., 2016 — The peptidergic control circuit for sighing (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.
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