The evidence, honestly
We would rather tell you what is uncertain than promise too much. This page summarises what research says about the breathing in this app, and what we deliberately do not claim.
What we know
- Slow breathing reliably changes heart-rate rhythms while you do it and shortly afterwards.
- Breathing faster or deeper than needed can cause dizziness and tingling — so gentle, ordinary-sized breaths are safest.
- Relaxation techniques, including breathing, are generally safe for healthy people.
- They are not a substitute for professional care.
What is promising
- Combined trials link breathing practices with modestly lower self-reported stress, anxiety and low mood.
- A longer, relaxed out-breath may be especially helpful for mood, based on one randomised trial.
- Short daily practice (around five minutes) appears to be enough to notice something, for some people.
What remains uncertain
- Whether any specific rhythm (such as six breaths a minute) is better than other gentle, guided breathing.
- How much of the benefit comes from breathing itself versus attention, expectation or simply taking a pause.
- Whether breathing exercises improve sleep, or help people with specific mental health conditions.
- Long-term effects of regular practice.
- Whether breath holds add anything — so they are always optional here.
What this app does NOT claim
- It does not diagnose, treat or cure anxiety, depression, panic, PTSD or any other condition.
- It does not 'reset' your vagus nerve or nervous system, detox the body, or release trauma.
- It cannot tell how you are doing, and it never scores your mood.
- It does not replace therapy, medication decisions, or emergency care.
How we grade evidence
- Evidence: Well established Consistent findings across many studies or systematic reviews; unlikely to change.
- Evidence: Some evidence Supported by meta-analysis of randomised trials, but with small samples, modest effects or risk of bias.
- Evidence: Early evidence Early or indirect evidence (single trials, related techniques, expert guidance). Plausible but not settled.
- Evidence: Uncertain Evidence is mixed, absent or does not support a specific claim.
Evidence registry
Each breathing pattern in Saans is linked to an entry below. The public wording on every page is kept within what the entry supports.
| Practice | Pattern | Evidence | What we say | Safety | Sources |
|---|---|---|---|---|---|
| Slow paced breathing without breath holds | Roughly 6–8 breaths per minute (e.g. 4/4, 4/5, 4/6), comfortable breath size | Some evidence Meta-analysis of RCTs; systematic reviews of physiological effects |
Research on slow, paced breathing suggests it can help some people feel less stressed. Studies are mostly small and effects are modest, so it is best thought of as one useful tool among many. | Generally well tolerated. Keep breath size natural to avoid over-breathing. Stop if dizzy or uncomfortable. | Fincham GW, Strauss C, Montero-Marin J, Cavanagh K Zaccaro A, Piarulli A, Laurino M, et al Laborde S, Allen MS, Borges U, et al |
| Exhale-emphasis breathing | Out-breath longer than in-breath (e.g. 3/5, 4/6, 4/7) | Early evidence One RCT of a related exhale-focused pattern (cyclic sighing); broader slow-breathing evidence |
Patterns that let the out-breath be a little longer have shown promise in early research. The studied pattern differs from ours, and no single ratio has been shown to be best. | Out-breath should be relaxed, not forced or squeezed. Quicker pace option provided. | Balban MY, Neri E, Kogon MM, et al Fincham GW, Strauss C, Montero-Marin J, Cavanagh K |
| Coherent / resonance-style breathing | About 5–6 breaths per minute, equal in and out | Uncertain Meta-analysis of physiological effects (established for HRV during practice); placebo-controlled RCT showing no added mental-health benefit over a 12 breaths/min paced control |
Breathing at about six breaths a minute reliably changes heart-rate rhythms while you do it. Whether this exact pace helps mood more than other gentle, guided breathing is uncertain: a large placebo-controlled trial found no extra benefit. | Slower than many people find natural; can feel like air hunger. Offer quicker pace and alternatives. | Laborde S, Allen MS, Borges U, et al Sevoz-Couche C, Laborde S Fincham GW, Strauss C, Cavanagh K |
| Box breathing with optional pauses | 4 in, 4 rest, 4 out, 4 rest | Early evidence Included as one arm of a single RCT; less benefit on positive mood than the exhale-focused arm |
Box breathing has been studied less than simple slow breathing. The pauses are not known to be essential to any benefit, so they are optional here. | Breath retention is never required. Pauses default to a relaxed rest and can be switched off. People who are pregnant or have heart, lung or blood-pressure conditions may prefer no pauses. | Balban MY, Neri E, Kogon MM, et al |
| Natural breath awareness (no pacing) | No pacing; noticing prompts every 10 s | Early evidence Component of multicomponent relaxation and self-help programmes; expert guidance |
Simply noticing your breath without changing it is a common first step in many relaxation approaches. It is gentle, but there is little research on it as a stand-alone exercise. | Internal focus can occasionally increase unease, especially after trauma. Alternative outward-focused exercise offered. | World Health Organization National Center for Complementary and Integrative Health (NIH) Zaccaro A, Piarulli A, Laurino M, et al |
| Outward-focused grounding (Look Around) | No breath focus; noticing sights, sounds, contact points | Early evidence Included in WHO self-help guide and course; not tested as a stand-alone exercise |
Grounding — noticing what you can see, hear and feel around you — is one of the skills in the World Health Organization's self-help stress guide. | Eyes open; self-paced. | World Health Organization World Health Organization |
| Counting as an attention anchor during slow breathing | 4/6 with on-screen counts | Early evidence Plausible rationale; counting itself not specifically tested in sources held here |
Counting gives attention a simple task. We include it because many people find it helpful, not because it has been specifically proven. | Mind-wandering is normalised to avoid self-criticism. | Zaccaro A, Piarulli A, Laurino M, et al Fincham GW, Strauss C, Montero-Marin J, Cavanagh K |
| Pre-sleep slow breathing | 4/6, night palette, minimal stimulation; or gradual slowing to 4/7 | Early evidence Indirect (slow-breathing evidence); NIH notes weak evidence for relaxation improving sleep |
A slow, quiet rhythm can make winding down feel easier. Evidence that breathing exercises improve sleep itself is limited. | Not a treatment for insomnia. Low-luminance visuals. | National Center for Complementary and Integrative Health (NIH) Fincham GW, Strauss C, Montero-Marin J, Cavanagh K |
| Avoiding over-breathing | All protocols: natural breath size, no fast or forceful breathing | Well established Standard physiology (government medical encyclopaedia) |
Breathing faster or more deeply than you need can lower carbon dioxide in the blood and make you feel dizzy or tingly. That is why we never ask for bigger breaths. | Dizziness, tingling or light-headedness are signals to stop and breathe normally. | MedlinePlus Medical Encyclopedia (US National Library of Medicine) |
| Breathing as a supportive tool, not treatment | All | Well established Government guidance |
Relaxation and breathing exercises are generally safe, but they are not a replacement for professional care. | Never replace professional care; support pathway always visible. | National Center for Complementary and Integrative Health (NIH) National Center for Complementary and Integrative Health (NIH) World Health Organization |
Sources
- Fincham GW, Strauss C, Montero-Marin J, Cavanagh K. Effect of breathwork on stress and mental health: a meta-analysis of randomised-controlled trials. Scientific Reports. 2023;13:432. Meta-analysis of randomised controlled trials. doi:10.1038/s41598-022-27247-y (opens in a new tab) Across 12 RCTs (785 adults), breathwork was associated with lower self-reported stress than non-breathwork controls, with a small-to-medium effect; anxiety and depressive-symptom outcomes showed similar small effects. The authors note small samples and moderate risk of bias, and advise cautious interpretation.
- Fincham GW, Strauss C, Cavanagh K. Effect of coherent breathing on mental health and wellbeing: a randomised placebo-controlled trial. Scientific Reports. 2023;13. Randomised placebo-controlled trial. doi:10.1038/s41598-023-49279-8 (opens in a new tab) 400 participants practised paced breathing about 10 minutes a day for 4 weeks at ~5.5 breaths/min or at 12 breaths/min (attention placebo). Stress, anxiety, depression and wellbeing improved over time in both groups, with no difference between them.
- 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. Randomised controlled trial (remote). doi:10.1016/j.xcrm.2022.100895 (opens in a new tab) PMC9873947. Daily 5-minute practices for a month: an exhale-focused breathing pattern (cyclic sighing), box breathing, cyclic hyperventilation with retention, or mindfulness meditation. The exhale-focused pattern produced greater improvement in positive mood and lower respiratory rate than mindfulness meditation. Single trial; healthy adults.
- Laborde S, Allen MS, Borges U, et al. Effects of voluntary slow breathing on heart rate and heart rate variability: a systematic review and a meta-analysis. Neuroscience & Biobehavioral Reviews. 2022;138:104711. Systematic review and meta-analysis. doi:10.1016/j.neubiorev.2022.104711 (opens in a new tab) 223 studies. Voluntary slow breathing increased vagally-mediated heart rate variability during practice, immediately after a session and after multi-session interventions; few adverse effects expected. This concerns physiological measures, not mental-health outcomes.
- Zaccaro A, Piarulli A, Laurino M, et al. How breath-control can change your life: a systematic review on psycho-physiological correlates of slow breathing. Frontiers in Human Neuroscience. 2018;12:353. Systematic review. doi:10.3389/fnhum.2018.00353 (opens in a new tab) PMID 30245619. 15 studies in healthy people. Slow breathing (<10 breaths/min) was associated with autonomic, brain-activity and psychological changes. The authors state the mechanisms are still under debate, and distinguish slow breathing from simple breath awareness or counting.
- Sevoz-Couche C, Laborde S. Heart rate variability and slow-paced breathing: when coherence meets resonance. Neuroscience & Biobehavioral Reviews. 2022;135:104576. Narrative review. doi:10.1016/j.neubiorev.2022.104576 (opens in a new tab) PMID 35167847. Reviews proposed mechanisms of breathing near ~0.1 Hz (about 6 breaths/min). Describes the mechanisms as multiple and complex; mechanistic proposals here are hypotheses, not established facts.
- World Health Organization. Doing What Matters in Times of Stress: An Illustrated Guide. Geneva: WHO; 2020. ISBN 9789240003927. WHO self-help guide (evidence-informed, field-tested). https://www.who.int/publications/i/item/9789240003927 (opens in a new tab) A brief, illustrated stress-management guide with audio exercises, intended for anyone experiencing stress. Includes grounding and noticing skills practised for a few minutes a day. Used here as a design reference for accessible, low-burden self-help.
- World Health Organization. Self-Help Plus (SH+): a group-based stress management course for adults. Geneva: WHO; 2021. WHO programme description. https://www.who.int/publications/i/item/9789240035119 (opens in a new tab) WHO's five-session group course that uses the Doing What Matters guide and audio. Cited for context only: it is a multicomponent programme, so its results cannot be attributed to any single exercise in this app.
- National Center for Complementary and Integrative Health (NIH). Relaxation Techniques: What You Need To Know. Government health information (US NIH). https://www.nccih.nih.gov/health/relaxation-techniques-what-you-need-to-know (opens in a new tab) Relaxation techniques are generally considered safe for healthy people. Occasional reports of increased anxiety, intrusive thoughts or fear of losing control; rare reports that some techniques may worsen symptoms in people with epilepsy, certain psychiatric conditions, or a history of abuse or trauma. Evidence for specific conditions is mixed; evidence on sleep is weak. Page content dated June 2021 at time of checking.
- National Center for Complementary and Integrative Health (NIH). 5 Things To Know About Relaxation Techniques for Stress. Government health information (US NIH). https://www.nccih.nih.gov/health/tips/things-to-know-about-relaxation-techniques-for-stress (opens in a new tab) Relaxation techniques are generally safe but evidence of usefulness for specific health conditions is limited. They should not replace conventional care or delay seeing a health professional.
- MedlinePlus Medical Encyclopedia (US National Library of Medicine). Hyperventilation. Government health information (US NLM). https://medlineplus.gov/ency/article/003071.htm (opens in a new tab) Over-breathing lowers carbon dioxide in the blood, which causes many of the symptoms of hyperventilation, including light-headedness, dizziness, and numbness or tingling around the mouth or in the arms. Basis for this app's 'no bigger breaths' and 'stop if dizzy' guidance.
Sources last checked: 2026-10-03. Every scientific statement shown to the public must trace to an entry below and must not exceed its 'publicWording'. Sources were located and their bibliographic details (title, journal, DOI/PMID/URL) confirmed against publisher or indexing records on the date checked. Summaries are paraphrased. If a source is retracted or superseded, downgrade the entry rather than strengthening the wording elsewhere.