Cyclic Sighing, Slow Breathing or Box Breathing: What Does the Evidence Show?
Compare breathing practices by what they change: feelings, breathing rate, HRV or sleep. Includes a 2026 everyday-life study and practical ways to interpret the results.
Updated 2026-11-13 · Archived
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Choose the outcome before choosing a technique
Breathing exercises can help some people feel calmer, but evidence for a change in mood is different from evidence for improved sleep, lasting HRV change or recovery from chronic stress. Current studies do not establish one technique as best for all of these outcomes.[1][2][3]
For everyday use, ask a simple question first: do you want a brief pause from feeling tense, or are you trying to change a measured health outcome? This guide compares the research without turning a breathing pattern into a universal recovery treatment.
How are the breathing patterns different?
A physiological sigh is a natural breathing event. Cyclic sighing is a deliberately repeated exercise built around a similar pattern. Evidence for a repeated practice should not be presented as proof that one spontaneous sigh has the same effect.[1]
| Practice | Typical pattern | What to distinguish |
|---|---|---|
| Cyclic sighing | A double inhalation followed by a longer exhalation, repeated. | A repeated exercise is different from one natural sigh. |
| Slow paced breathing | Following a slower rhythm; studies often use about six breaths a minute. | Slow describes rate, not a requirement to take the largest possible breath. |
| Box breathing | Inhale, hold, exhale and hold in equal phases. | The holds are part of the pattern; “4–4–4–4” is one example, not a universal dose. |
What did the five-minute breathing trial find?
Balban’s 2023 remote trial compared daily breathing practices with mindfulness meditation for 28 days. Cyclic sighing showed advantages for positive affect and respiratory rate relative to meditation. HRV, resting heart rate and sleep measures did not show significant changes. Between-group anxiety results did not establish a breathing advantage.[1]
This is a useful distinction: someone may feel better without a measurable change in every physiological signal. The small, exploratory trial does not settle long-term effects or which technique will suit a particular person.
Why can HRV rise during slow breathing?
Breathing changes the timing of heartbeats. A higher HRV value recorded while deliberately slowing the breath is therefore not equivalent to a higher resting value measured under usual conditions. Keep the measurement condition attached to the number.[4]
Laborde’s meta-analysis separates HRV during practice, immediately after one session and after repeated sessions. It found increases in RMSSD, an HRV measure, at each time point. Most included studies had high risk of bias, and results varied. This supports studying a physiological response, not using a practice-time HRV rise as proof of complete recovery.[2]
A useful personal comparison keeps the device, time, posture and breathing condition similar. Do not compare a paced-breathing session with an overnight device score as if they were the same test.
What happens when slow and box breathing are compared directly?
A 2025 experiment in 84 students compared four patterns within the same people. Six breaths per minute produced larger HRV increases during practice than square or 4–7–8 breathing, but did not establish better mood or blood pressure. Mild over-breathing also occurred.[5]
The lesson is to separate a larger physiological signal from a better overall outcome. This study did not include cyclic sighing or test effects over weeks.
What does the 2026 everyday-life study add?
In a small study of 47 university students, roughly one minute of cyclic sighing or box breathing was followed by lower reported anxiety than a passive control condition at the short follow-up. The anxiety comparison did not clearly distinguish the two breathing methods.[3]
The attention findings were mixed: box breathing was associated with fewer inhibition errors, but responses were slower after both exercises. No physiological outcomes were measured. Feeling calmer, responding faster and making fewer errors are separate goals.
What can you reasonably expect?
Read each row as a separate question. Improvement in one row cannot fill an evidence gap in another.
| Your question | What to look for | What does not answer it |
|---|---|---|
| Can it help me feel less tense now? | A before/after experience, interpreted alongside controlled comparisons. | A claim that all stress physiology has normalized. |
| Does it change HRV? | The HRV metric and whether measurement was during practice or at rest. | A number without recording conditions. |
| Does it improve sleep? | Sleep outcomes measured across an appropriate period. | Relaxation alone; the Balban trial did not show significant sleep changes. |
| Does it make work performance better? | The particular task: speed, accuracy or sustained attention. | Treating calmness as proof of better performance on every task. |
How to try a brief practice without chasing a score
Start with a comfortable seated pause and an easy rhythm. The study descriptions above explain the techniques; they are not targets to force. If deliberate breathing causes dizziness, breathlessness or discomfort, stop the exercise and return to ordinary breathing. A person with a condition affecting breathing should discuss suitability with their clinician.
Notice the outcome that matters to you: how tense you feel, whether the practice is comfortable and whether it helps you return to your next activity. Repeat observations on more than one occasion; a single good moment cannot show that a method caused lasting change.
If your main problem is worry that continues after an event, breathing can be one way to pause. It does not by itself resolve the continuing workload, the worry process or a sleep problem. These require their own questions and evidence.
Source scope, funding and a finding still to check
The selected sources include the Balban full text, Laborde’s accepted manuscript Riedl’s published full text and the Marchant published PDF. Individual protocols, comparisons and measurement windows differ; the studies do not validate a general “nervous-system reset”. Funding and interests are retained in each research note.
Balban reported donated WHOOP devices and an author’s WHOOP advisory role. Laborde’s authors reported no funding source or conflicts; Riedl reported university postdoctoral funding and no potential conflicts. These are the authors’ declarations, not an independent audit. Marchant reported Brigham Young University funding and no conflicts.
A September 2026 box-breathing review is retained as a source requiring clarification: its abstract gives both eight eligible trials and “29 RCTs”. Until its study count and full text can be reconciled, this guide does not use it to estimate effects or rank methods.
References
- Balban MY, Neri E, Kogon MM, Weed L, Nouriani B, Jo B, Holl G, Zeitzer JM, Spiegel D, Huberman AD (2023). Brief structured respiration practices enhance mood and reduce physiological arousal. Cell Reports Medicine. https://doi.org/10.1016/j.xcrm.2022.100895
- Sylvain Laborde et al. (2022). Effects of voluntary slow breathing on heart rate and heart rate variability: A systematic review and a meta-analysis. Neuroscience & Biobehavioral Reviews. https://doi.org/10.1016/j.neubiorev.2022.104711
- Elisabeth M. Riedl, Teresa Bracklo, Kathrin Wimmer, Johanna Perzl, Hans-Juergen Gdynia, Joachim Thomas, Janusz Surzykiewicz (2026). Simply breathing anxiety away? A pilot, just-in-time ecological momentary intervention study of one-minute cyclic sighing versus box breathing as tools for acute anxiety reduction and attention promotion in real life. Anxiety, Stress, & Coping. https://doi.org/10.1080/10615806.2026.2659809
- Sylvain Laborde, Emma Mosley, Julian F. Thayer (2017). Heart Rate Variability and Cardiac Vagal Tone in Psychophysiological Research - Recommendations for Experiment Planning, Data Analysis, and Data Reporting. Frontiers in Psychology. https://doi.org/10.3389/fpsyg.2017.00213
- Joshua Marchant, Inna Khazan, Mikel Cressman, Patrick Steffen (2025). Comparing the Effects of Square, 4–7-8, and 6 Breaths-per-Minute Breathing Conditions on Heart Rate Variability, CO2 Levels, and Mood. Applied Psychophysiology and Biofeedback. https://doi.org/10.1007/s10484-025-09688-z
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