Why this exists
Most "calm" breathing apps are subscription mazes with too many guided sessions and not enough actual evidence. This one operationalizes one specific, research-backed pattern — 4-4-4-4 box breathing — with a clean visual pacer and nothing else.
Slow breathing and blood pressure
Slow paced breathing — anywhere from about 3 to 6 breaths per minute — has been shown in multiple randomized trials to lower both systolic and diastolic blood pressure. Mechanism: shifting the autonomic balance toward parasympathetic activity via baroreceptor coupling.[1]
A 2017 review in the journal Breathe summarizing the evidence concluded that slow breathing techniques are a safe, easy adjunct to standard hypertension care. They don't replace medication — but they meaningfully add to it. Box breathing at 4-4-4-4 (≈3.75 breaths/min) sits well within the effective range.[2]
Slow breathing and anxiety
A 2023 Stanford randomized controlled trial (Balban, Spiegel, et al., Cell Reports Medicine) compared three breathing protocols against mindfulness meditation over four weeks. All four reduced anxiety; cyclic sighing — emphasizing prolonged exhalation — performed best. Box breathing also worked; it just wasn't the winner.[3]
The honest takeaway: any consistent slow-breathing practice helps. The specific protocol matters less than doing it. Pick one you'll actually use.
What this app does
It paces one cycle of box breathing — 4 seconds in, 4 hold, 4 out, 4 hold. The expanding circle is the only thing you have to watch. You can run it as long as you like; press Stop when you're done.
No accounts. No streaks. No upsell. Source code is open under AGPL-3.0. If you want a different pattern, future versions will add a picker — for now, this is the default that's good for most people.
References
- [1] Russo MA, Santarelli DM, O'Rourke D. *The physiological effects of slow breathing in the healthy human.* Breathe. 2017;13(4):298–309. PubMed
- [2] Schein MH, Gavish B, Herz M, et al. *Treating hypertension with a device that slows and regularises breathing: a randomised, double-blind controlled study.* Journal of Human Hypertension. 2001;15(4):271–278. PubMed
- [3] Balban MY, Neri E, Kogon MM, et al. *Brief structured respiration practices enhance mood and reduce physiological arousal.* Cell Reports Medicine. 2023;4(1):100895. Cell Reports Medicine