Cyclic Sighing vs Box Breathing: Which One the Trial Actually Favored
Roon Team
Cyclic Sighing vs Box Breathing: Which One the Trial Actually Favored
It's a split decision. In the one month-long trial that compared box breathing vs cyclic sighing head to head, cyclic sighing produced the largest improvement in positive mood and the biggest drop in breathing rate. But in a 2026 pilot field study that tested both during real stressful moments, box breathing was the technique linked to fewer errors on an attention test. Cyclic sighing was not. And neither technique changed heart rate variability.
Most pages on this topic declare a winner by ignoring half the data. Here is the full picture.
Key Takeaways
- Cyclic sighing wins on mood. Over 28 days, it beat mindfulness meditation on positive affect improvement. Box breathing improved mood too, but cyclic sighing accumulated the advantage faster (Balban et al. 2023).
- Box breathing wins on accuracy. In a 2026 pilot field study, box breathing was associated with fewer inhibition errors on an attention test. Cyclic sighing was not (Riedl et al. 2026).
- Neither changes resting HRV or heart rate. The month-long trial measured both and found nothing in any group.
- Both reduce state anxiety about equally. Neither technique beat the other, and neither beat mindfulness meditation on the anxiety measure.
The Two Techniques
Cyclic sighing (the physiological sigh): Inhale slowly through the nose until the lungs are comfortably full. Take a second, shorter sip through the nose to fill them completely. Then exhale slowly and fully through the mouth. Repeat. For a full walkthrough of both patterns, see this breathwork guide.
Box breathing: Inhale for a set count, hold for that count, exhale for that count, hold again for that count. Most people use four seconds per phase (4-4-4-4). If breath holds feel uncomfortable, drop them and lengthen the exhale instead.
The Month-Long Trial (Balban et al. 2023)
The only RCT that ran these two techniques against each other is Balban et al. 2023, published in Cell Reports Medicine. Remote trial, 108 participants, four arms, five minutes a day for 28 days.
| Arm | n | Protocol |
|---|---|---|
| Cyclic sighing | 30 | Prolonged exhale, double-inhale pattern |
| Box breathing | 21 | Equal inhale, hold, exhale, hold |
| Cyclic hyperventilation with retention | 33 | 30 fast breaths, then 15-second breath hold |
| Mindfulness meditation (control) | 24 | Passive awareness of breath and body |
The box breathing arm had only 21 people. That limits the statistical power for any head-to-head comparison, and the authors acknowledged it.
What Cyclic Sighing Actually Won
Cyclic sighing produced the steepest trajectory of positive affect improvement over the 28 days. That trajectory was higher than the mindfulness meditation arm (p < 0.05), and the advantage accumulated with adherence, showing up as a clear interaction with cumulative days on protocol.
All three breathwork arms showed daily positive affect improvements that were close to one another on any given day, and all three outpaced the mindfulness meditation arm. The separation is in the accumulation: cyclic sighing pulled ahead of meditation over time. Box breathing's daily gains were nearly identical, but the trajectory analysis favored the sighing group. Cyclic sighing also reduced resting breathing rate (p < 0.05) compared with meditation. Box breathing did not.
What Nothing Won
This section matters more than the one above, because it corrects the two claims you will find on almost every other page about this trial.
The anxiety tie. State anxiety fell in every group, breathwork and meditation alike, with no meaningful difference between them. Cyclic sighing did not "beat meditation on anxiety." Neither did box breathing. If a page tells you otherwise, it is misreading the paper. For a deeper look at what mindfulness does for attention and the brain, that deserves its own read.
The HRV null. The study's own words: "No significant changes were found in heart rate variability or resting heart rate over the course of the study in either of the groups." Zero movement, in any arm, after a month.
If you are judging a breathing practice by your wearable's overnight HRV number, this trial gives you no reason to expect it to move.
A Necessary Nuance on HRV
That null does not mean slow breathing is inert for HRV in general. A 2022 meta-analysis of 223 studies (Laborde et al., Neuroscience and Biobehavioral Reviews) found that voluntary slow breathing increases vagally-mediated HRV during a session, immediately after, and after multi-session interventions. Both findings coexist. Slow breathing shifts HRV in the moment, but five minutes a day for a month did not shift resting HRV measured across the day.
The 2026 Pilot Study Nobody Is Citing
Riedl et al. 2026, published in Anxiety, Stress and Coping, ran a different design. Forty-seven university students used a phone app whenever they felt tense or distressed in daily life. They completed a state measure, were assigned to one of three conditions (one-minute cyclic sighing, one-minute box breathing, or a passive control), and re-measured five minutes later. Total: 782 usable measurements. The authors describe this as a preregistered pilot study.
On anxiety reduction: Both techniques beat the passive control. Cyclic sighing coefficient: b = -0.73 (p < .01). Box breathing coefficient: b = -0.80 (p < .01). Essentially equivalent.
On attention accuracy: Box breathing was the only technique linked to fewer inhibition errors on a subsequent attention test (b = -0.29, p = .04). Cyclic sighing showed no effect (b = -0.10, p = .27). The accuracy benefit was stronger for highly anxious individuals.
The trade-off: Both techniques slowed reaction times relative to control. More accurate, but slower. This fits how arousal regulation trades off with speed.
Why Box Breathing Might Improve Accuracy
The Riedl team pointed to Röttger et al. 2021 (Applied Psychophysiology and Biofeedback). In that laboratory study, box breathing was compared with prolonged exhalation performed during a Stroop task under time pressure and noise. Prolonged exhalation outperformed box breathing on task performance, while box breathing produced lower physiological arousal.
The interpretation: box breathing's four-phase structure is cognitively demanding enough to compete for resources during a task. But that same cognitive load may function as a brief attentional reset before a task, priming the controlled, inhibition-heavy processing that reduces errors. Practical rule: box breathing before the task, not during it.
The Verdict Table
| Criterion | Cyclic Sighing | Box Breathing |
|---|---|---|
| Mood improvement over weeks | Strongest trajectory in the month-long trial | Similar daily gains, but slower accumulation |
| Breathing rate reduction | Reduced (p < 0.05) vs meditation | No change vs meditation |
| State anxiety reduction | Yes, but no better than meditation or box breathing | Yes, but no better than meditation or cyclic sighing |
| Attention accuracy (fewer errors) | No detected effect | Fewer inhibition errors (p = .04) |
| Reaction time | Slower than control | Slower than control |
| Resting HRV change | None detected | None detected |
| Resting heart rate change | None detected | None detected |
| Best use case | Daily mood regulation, pre-sleep wind-down | Before a presentation, exam, or high-accuracy task |
What Neither One Is
Neither technique is a treatment for any condition. Neither has been shown to change resting heart rate. Neither has strong evidence behind the "Navy SEAL validated" framing that circulates online.
The trials here are small (108 and 47 participants), largely young, and predominantly female in the 2026 pilot study, and short. They are good enough to inform personal experiments, not enough to make clinical recommendations. For a broader look at the stress system these techniques act on, consider how the HPA axis shapes the stress response.
Conclusion
You probably do not need to choose. Cyclic sighing is better studied for sustained mood improvement over weeks. Box breathing has the only evidence for sharpening accuracy before a demanding task. Neither changes your wearable's HRV score, and both reduce how anxious you feel in the moment about equally.
Use cyclic sighing as a daily five-minute practice. Use box breathing as a pre-performance reset. And if you have twenty minutes instead of one, time outside, which runs on a different evidence base entirely, is worth considering.
Frequently Asked Questions
Which is better, cyclic sighing or box breathing?
Neither is categorically better. In a month-long trial, cyclic sighing produced the steepest mood improvement. In a 2026 pilot field study, box breathing was linked to fewer errors on an attention test. Cyclic sighing for how you feel over time; box breathing for accuracy before a high-stakes task.
Does box breathing actually work?
Yes, with caveats. It reduced state anxiety relative to a passive control in the 2026 pilot study, improved mood over a month in the Balban trial, and reduced inhibition errors on an attention test. It did not outperform meditation on anxiety, and it did not change resting HRV or heart rate.
How long do you have to practice before it does anything?
One minute reduced state anxiety in the Riedl 2026 pilot study. For mood improvement that accumulates, the Balban trial used five minutes a day for 28 days, and the effect built with each day of adherence. You can feel something quickly, but you gain more with consistency.
Does cyclic sighing raise HRV?
Not resting HRV, based on the one month-long trial that measured it. Slow breathing in general does increase vagally-mediated HRV during and immediately after a session, according to a meta-analysis of 223 studies. But five minutes a day for a month did not shift all-day resting HRV in any group.
Can you do box breathing while you work?
With caution. A laboratory study found that prolonged exhalation outperformed box breathing during a cognitively demanding task, likely because monitoring four breathing phases competes for attentional resources. Box breathing works better as a pre-task reset than a mid-task tool.
Is one better right before a presentation?
Box breathing has the edge here. It was the only technique in the 2026 pilot study associated with fewer inhibition errors, and that effect was strongest in highly anxious individuals. Do it for one minute before you go on, not while you are speaking. Cyclic sighing is a reasonable alternative if breath holds feel uncomfortable.
Breathwork Handles Arousal, Not the Energy Floor Beneath It
Cyclic sighing and box breathing both regulate the autonomic dial. Neither one generates sustained cognitive energy. If your afternoon focus collapses not because you are anxious but because you are simply running out of fuel, a breathing protocol is the wrong tool for the job.
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Roon is not a substitute for the breathing practices covered here, and it does not treat anxiety. Pair it with your pre-task box breathing or your daily sighing habit if you want both the calm and the current. Pouches start at as little as $0.61 each. Try Roon for your next deep-work block.
Written by Roon Team
