Box Breathing, Resonance-Frequency Breathing and Heart-Rate-Variability Biofeedback
An overview of named breathing methods: box breathing, 4-7-8, resonance-frequency (about 6 breaths a minute) breathing and HRV biofeedback, with what trials found, mixed results and cautions.
Content last updated . This page has not been medically reviewed.
Named patterns versus tested methods
Many breathing methods have catchy names and counts. Few have been compared head to head. This page separates what was tested from what is popular. For the simpler practices these build on, see gentle breathing and relaxation practices; for the goal-level view, see breathing exercises for stress. Several named methods include pauses. We do not give counts or hold instructions, and we do not recommend long holds. If you feel lightheaded or tingly, stop and breathe normally, since overbreathing causes those symptoms. [1] Do not practice while driving, bathing, swimming, near water or at heights; see breathwork safety.Box breathing
Box breathing uses equal-length phases: in, pause, out, and sometimes a pause again. One remote trial gave people daily 5-minute practices for a month and compared them with mindfulness meditation. Breathwork overall improved mood more, and the exhale-focused cyclic sighing stood out. [2] Box breathing was one of three practices in that trial and was not reported as better than the others. Other small trials found lower state anxiety and smaller stress-test reactions after box breathing than after normal breathing. [3][4] Box breathing during recovery from hard cycling gave higher heart rate and effort than slower breathing at 6 breaths a minute. [5]Label: promising but limited. Nothing we read supports a specific count or hold length. Full detail is on the box breathing page.
4-7-8 breathing
Several small trials exist. Randomized trials around surgery and procedures reported lower anxiety than routine care, and one tinnitus trial lowered questionnaire scores. [6][7][8] In 84 students, 6 breaths a minute raised heart rate variability more than 4-7-8 breathing, and none of the patterns changed blood pressure or mood meaningfully. [9] Label: promising but limited; claims that it fixes insomnia or lowers blood pressure are not established. See the 4-7-8 page.Resonance-frequency breathing
Resonance-frequency (also called coherent) breathing means breathing at the personal rate, often near 6 breaths a minute, where heart-rate and breathing rhythms line up. A 2020 review concluded that breathing at 6 breaths per minute could induce coherence of 0.1 Hz heart and brain oscillations, which the authors link to physical and psychological function. [10] That is a proposed mechanism and physiological finding, not proof that it improves health outcomes. A systematic review of slow breathing under 10 breaths a minute in healthy people found increased heart rate variability, more alpha and less theta brain activity on EEG, and psychological changes such as more relaxation and less anxiety. [11] That applies to slow breathing in general, not to one ratio.One caution: in the student comparison, breathing at 6 breaths a minute led to mild overbreathing, so a slow rate is not automatically gentle for everyone. [9] See paced and resonance-frequency breathing.
We did not find trials comparing resonance-breathing apps with plain slow breathing, so proper evidence not found for that comparison.
Heart-rate-variability biofeedback (HRV-B)
In HRV biofeedback, a sensor shows your heart rhythm while you adjust your breathing to increase heart rate variability. NCCIH describes it as receiving data on your heart rate from a device and using breathing techniques to change your heart rate pattern. [12] Devices and scores are covered on HRV biofeedback.| Question | What the source found | Strength of evidence |
|---|---|---|
| Stress and anxiety | 24 studies (484 people): large reductions in self-reported stress and anxiety (Hedges g about 0.8); the authors said more well-controlled studies were needed [13] | Promising but limited |
| Remote programs (2026) | 18 studies (1,352 people): medium benefit for depression and for HRV; the effect on stress was not significant [14] | Mixed |
| Military PTSD | 5 small studies (95 people): moderate to large reductions in symptoms [15] | Insufficient evidence (very small studies) |
| Blood pressure | Slow breathing, with or without a device, gave a modest drop in 17 trials, with high variation [16]; a 2022 review of 22 studies found device-guided slow breathing did not significantly reduce blood pressure versus usual care [17] | Mixed |
Participants know whether they are doing biofeedback, so expectation and attention may add to results. A wearable that displays "HRV" is not the same as a structured biofeedback program; see wearables for breathing rate and HRV.
Practitioners and cost
Who delivers biofeedback and how they are trained varies by country, and we did not find a regulator or professional-body page to cite, so proper evidence not found for one standard. Ask about the person's training, whether they work within a licensed health profession where you live, and what the plan is if it does not help. We do not list practitioners or prices.Frequently asked questions
Is box breathing better than other breathing?
Not shown. One trial found several brief breathing practices improved mood more than mindfulness, with cyclic sighing doing best. [2]
Does 4-7-8 breathing work?
Small trials found lower anxiety around procedures; it did not beat 6 breaths a minute for HRV in students. [6][9]
What is resonance breathing?
Breathing at about 6 breaths per minute, where heart and breathing rhythms line up. [10]
Is HRV biofeedback effective for anxiety?
A meta-analysis of 24 studies found large reductions in self-reported stress and anxiety, but asked for better-controlled studies. [13]
Can it lower blood pressure?
Slow breathing produced a modest drop in a meta-analysis. If you have high blood pressure, follow your prescribed treatment. [16][12]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Who should check first
Anyone with a heart condition, blood pressure problems, epilepsy or a psychiatric condition should talk with their clinician before starting a program. NCCIH notes rare problems with relaxation techniques in people with epilepsy, certain psychiatric conditions, or a history of abuse or trauma, and advises people with high blood pressure to follow their prescribed treatment plan. [12]
References
- MedlinePlus Medical Encyclopedia, Hyperventilation. U.S. National Library of Medicine. Read 2026-10-22.
- Brief structured respiration practices enhance mood and reduce physiological arousal. Cell Rep Med 2023. PubMed 36630953. Read 2026-10-22.
- Box breathing and prolonged exhalation reduces markers of physiological stress reactivity in response to a virtual Trier Social Stress Test. Compr Psychoneuroendocrinol 2026. PubMed 42388906. Read 2026-10-22.
- Simply breathing anxiety away? A pilot, just-in-time ecological momentary intervention study of one-minute cyclic sighing versus box breathing. Anxiety Stress Coping 2026. PubMed 42002307. Read 2026-10-22.
- Box breathing or six breaths per minute: which strategy improves athletes post-HIIT cardiovascular recovery? PLoS One 2025. PubMed 41248139. Read 2026-10-22.
- The effect of stress ball and 4-7-8 breathing technique on preprocedure fear, anxiety, and physiological parameters in elderly patients undergoing endoscopy: a randomized controlled study. Gastroenterol Nurs 2026. PubMed 42715135. Read 2026-10-22.
- The effect of deep breathing exercise and 4-7-8 breathing techniques applied to patients after bariatric surgery on anxiety and quality of life. Obes Surg 2023. PubMed 36480101. Read 2026-10-22.
- The effect of 4-7-8 breathing exercise technique on tinnitus handicap, psychological factors, and sleep quality in tinnitus patients: a randomized controlled study. Brain Behav 2026. PubMed 41676854. Read 2026-10-22.
- Comparing the effects of square, 4-7-8, and 6 breaths-per-minute breathing conditions on heart rate variability, CO2 levels, and mood. Appl Psychophysiol Biofeedback 2025. PubMed 39864026. Read 2026-10-22.
- Heart rate variability (HRV): from brain death to resonance breathing at 6 breaths per minute. Clin Neurophysiol 2020. PubMed 31978852. Read 2026-10-22.
- How breath-control can change your life: a systematic review on psycho-physiological correlates of slow breathing. Front Hum Neurosci 2020. PubMed 30245619. Read 2026-10-22.
- NCCIH, Relaxation Techniques: What You Need To Know. U.S. National Institutes of Health. Read 2026-10-22.
- The effect of heart rate variability biofeedback training on stress and anxiety: a meta-analysis. Psychol Med 2018. PubMed 28478782. Read 2026-10-22.
- Efficacy and methodology of remote heart rate variability biofeedback interventions for mental health: a systematic review and meta-analysis. Appl Psychophysiol Biofeedback 2026. PubMed 41310318. Read 2026-10-22.
- Heart rate variability biofeedback as a treatment for military PTSD: a meta-analysis. Mil Med 2024. PubMed 38287778. Read 2026-10-22.
- Device and non-device-guided slow breathing to reduce blood pressure: a systematic review and meta-analysis. Complement Ther Med 2019. PubMed 31331557. Read 2026-10-22.
- Device and nondevice-guided slow breathing to reduce blood pressure in hypertensive patients: a systematic review and meta-analysis. Health Sci Rep 2022. PubMed 35601033. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.