Cyclic sighing: the Stanford-tested breathing technique that outperformed mindfulness on mood.

The trial, in plain terms

The study was published in Cell Reports Medicine in January 2023. The investigators were Melis Yilmaz Balban and colleagues, with senior authorship by Andrew Huberman of Stanford and David Spiegel, who runs the Stanford Center for Stress and Health. Participants were randomized to one of four daily practices: mindfulness meditation, box breathing, cyclic hyperventilation with retention (a version of Wim Hof breathing), or cyclic sighing. Each was practiced five minutes a day for twenty-eight days. Mood and physiological state were measured before, after, and across the month.

All four arms improved on mood and reduced respiratory rate. Cyclic sighing improved positive affect more than mindfulness, and reduced respiratory rate more than the other arms. The differences were modest in absolute terms but consistent, and the trial design was unusually clean for the category, with active comparators on both sides and a daily practice protocol that approximated the way real people use these techniques.

It is worth noting what the study did not show. It did not show that one technique cures anxiety. It did not isolate the mechanism. It did not run for years. It showed that, across one month of five-minute daily practice in a non-clinical population, one structured breathing pattern moved a measurable mood and physiological needle further than the others.

The technique, exact

The pattern itself is simple. Sit or lie down. Through the nose, breathe in to about three-quarters of your lung capacity. Without exhaling, take a second smaller inhale through the nose to top up the rest of the lungs. Then exhale slowly through the mouth, taking longer to exhale than you took to inhale. Repeat for about five minutes.

The double-inhale is the part that surprises most people on the first attempt. It reopens collapsed alveoli in the lungs and increases the surface area available for gas exchange. The long exhale activates the vagal slow-down on the heart, which is the part of the parasympathetic nervous system that lowers arousal. The two together produce the effect the trial measured.

The clinical literature also uses the name physiological sigh for the same pattern. Both names describe the same breathing rhythm. The neurobiologist Mark Krasnow described the physiological-sigh circuit in the brainstem in 2017, identifying a small cluster of neurons that drives the spontaneous sighs healthy mammals take every few minutes. Cyclic sighing is the same pattern done on purpose, more often.

The double-inhale reopens collapsed alveoli. The long exhale activates the vagal slow-down on the heart. The two together produce the effect the trial measured.

Why it works for panic

During panic, the breath gets shallow and fast. Carbon-dioxide levels drop and the body interprets the drop as a threat, which reinforces the panic loop. A short inhale and a long exhale break that loop directly: the exhale is the part of the breath that lowers heart rate and signals safety to the nervous system. The double-inhale fills the lungs without forcing a long, effortful breath the panicking body cannot quite finish.

In practical terms, cyclic sighing is one of the few interventions that works in the moment of panic, not only as a preventive practice. Most mindfulness techniques ask you to sit with what is happening; cyclic sighing changes what is happening in the body within ninety seconds. That is why Stillee uses it as the default rhythm in the panic flow.

It is not a cure for panic disorder, and it does not replace clinical care. It is a tool. Tools matter when the moment is acute.

What the trial cannot tell you

A small RCT in a non-clinical population is not enough to know whether cyclic sighing helps people with diagnosed panic disorder, post-traumatic stress, or generalized anxiety more than the comparators. The honest answer is that the larger evidence base on slow breathing as a whole is consistent across conditions, and cyclic sighing fits inside that base. But the single Stanford trial measured mood and respiratory rate in healthy adults, not clinical outcomes in patients.

It is also worth saying that mindfulness meditation in the comparator arm improved too. The trial does not mean mindfulness does not work. It means cyclic sighing worked better, for these outcomes, in this population, over this dose. If your daily practice is mindfulness and you want to keep it, keep it. Adding five minutes of cyclic sighing is a small addition.

How to start

A reasonable place to begin is one five-minute round in the morning, before the day picks up, for two weeks. The first sessions will feel awkward. The double-inhale takes practice and the long exhale takes more breath control than people expect on day one. By the end of the first week, the pattern usually starts to feel natural.

A guided audio shortens the learning curve. The Stillee panic flow opens with the rhythm already in motion, and the breathing room uses the same pattern as the hero of its Circuit Breaker shape, a short, repeatable reset you can reach any time. The visual on screen leads the rhythm, so you do not have to count.

• · Two short inhales through the nose, in succession, the second one smaller.
• · A long slow exhale through the mouth, taking longer than the inhale.
• · Five minutes a day for a month is the dose the trial studied.
• · Aim for a calm room, not a moving car or a noisy office.

What we built with this

Stillee uses cyclic sighing as the default in the panic flow because it is the technique with the strongest current evidence for acute mood shift and one of the cleanest patterns to learn from a phone. The same pattern anchors the Circuit Breaker shape in the breathing room, so you learn it once and meet it everywhere.

The technique is not proprietary to Stillee. The trial is public. The breathing pattern was known long before the trial named it. What we did was put the rhythm one tap away, without a paywall, with the visual leading the count. That is the part of the design that mattered, not the technique.