Cyclic Sighing, Slow Breathing or Box Breathing:
What Does the Evidence Show?

02How 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]

03What 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.

• Balban 2023: design, outcomes and disclosures ↗

04Why 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.

• Can HRV measure recovery? ↗
• Laborde 2022: measurement timing and evidence limits ↗

05What 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.

• Marchant 2025: direct comparison and carbon-dioxide findings ↗

06What 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.

• Riedl 2026: the full-text reading note ↗

07What can you reasonably expect?

Read each row as a separate question. Improvement in one row cannot fill an evidence gap in another.

08How 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.

• Why stress can continue after an event: perseverative cognition ↗
• What wearable recovery scores mean ↗

09Source 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.

• 2026 box-breathing review: abstract with inconsistent trial counts ↗