Breathing technique
Cyclic Sighing: the double-inhale, long-exhale breath and how to practise it
Cyclic Sighing is five minutes of repeated physiological sighs: two inhales through the nose, then one long exhale through the mouth. It is the breathing practice that improved mood most in a Stanford randomised trial of brief daily breathwork. Here is how to do it, what the evidence says, and who should take care.
Vayu paces Cyclic Sighing at 3-1-6 on Apple Watch and Wear OS, with a haptic pattern built so the two inhales feel like two separate breaths.
What is Cyclic Sighing?
Cyclic Sighing is a breathing practice made of repeated physiological sighs: a full inhale through the nose, a second short inhale on top to fill the lungs completely, then one long, slow exhale through the mouth. Practised for about five minutes a day, it was the most effective of the breathing exercises tested in a Stanford randomised trial.
The body already sighs on its own, several times an hour, and more often under stress. Research on spontaneous sighs suggests they act as a reset for the breathing pattern, with breathing becoming more structured after each one. Cyclic Sighing takes that reflex and turns it into a deliberate, repeated practice.
The exhale is the working part. It is roughly twice as long as the two inhales combined, which slows the breathing rate to about six breaths a minute and weights each breath toward the out-breath.
Is Cyclic Sighing the same as the physiological sigh?
Not quite. A physiological sigh is a single double-inhale and long exhale, which the body does on its own and you can do once or twice to settle quickly. Cyclic Sighing is the structured practice: the same breath repeated continuously for about five minutes. The trial evidence is for the five-minute practice, not a single sigh.
If you want one or two sighs in a tense moment, the explainer on the physiological sigh in our knowledge base covers the reflex itself. This page is about the repeated practice and how to build it into a day.
How do you do Cyclic Sighing?
Breathe in through the nose until the lungs are nearly full, then take a second, shorter sip of air through the nose to top them off. Breathe out slowly and completely through the mouth. Vayu paces this at 3-1-6: three seconds in, one second second inhale, six seconds out, with no holds, for two to eight minutes.
Get comfortable
Sit or lie down with your shoulders relaxed. Close your eyes if you like.
First inhale through the nose (3 seconds)
Breathe in steadily through the nose until the lungs feel nearly full.
Second, short inhale through the nose (1 second)
Without breathing out, take one more quick sip of air through the nose to fill the lungs completely.
Long exhale through the mouth (6 seconds)
Let the air out slowly and fully through the mouth, as if sighing. Let the shoulders drop.
Go straight into the next breath
There is no hold. Begin the next double inhale as soon as the exhale is complete.
Continue for about five minutes
The trial used five minutes a day for a month. Start with two minutes if five feels long.
If the second inhale feels strained, make the first inhale a little shallower. The second breath should be a small top-up, not a gasp.
What are the benefits of Cyclic Sighing?
In a randomised controlled trial, five minutes a day of Cyclic Sighing for a month improved mood more than the same time spent in mindfulness meditation, and lowered breathing rate at rest. It was the strongest of the three breathing exercises tested. Separate studies show that a longer exhale is what drives the relaxation effect.
Better mood than mindfulness meditation
Across three daily 5-minute breathwork practices and a mindfulness control, exhale-focused Cyclic Sighing produced the greatest improvement in positive mood and a larger reduction in resting respiratory rate than meditation, over one month. [1]
The long exhale does the work
Breathing with an exhale longer than the inhale increased self-reported relaxation, and at six breaths a minute it also increased high-frequency heart rate variability, compared with the reverse ratio. [2]
Sighs reset the breathing pattern
In 42 healthy adults, breathing became more structured after each spontaneous sigh, which the authors describe as a resetter effect. [3]
Slow breathing raises HRV
A meta-analysis found voluntary slow breathing increases vagally mediated heart rate variability during a session and afterwards. Cyclic Sighing runs at about six breaths a minute. [4]
Who should not do Cyclic Sighing?
Cyclic Sighing is a slow practice with no breath holds, so it suits most people. Slow down if you feel light-headed, which usually means the inhales are too big or too fast. People with severe lung disease, recent chest or abdominal surgery, or panic that deep breathing sets off should start gently and check with a clinician.
- Light-headedness or tingling: make the inhales smaller and the exhale slower, or stop
- Severe asthma or COPD: the double inhale can feel effortful; check with your respiratory team
- Recent chest or abdominal surgery: wait until your surgeon clears deep breathing
- Panic disorder: slow exhale-led breathing usually helps, but stop if focusing on the breath raises anxiety
- Pregnancy: generally fine as a slow practice; confirm with your provider
Never practise breathing exercises in or near water or while driving.
Read the full breathwork safety guidelines and the guide to breathwork contraindications. This is general education, not medical advice.
How does Vayu guide Cyclic Sighing on the wrist?
The two inhales have to feel like two breaths, so Vayu gives each its own texture. The first inhale is a ramp of taps that starts fast and slows, stopping early to leave a gap of silence. The second inhale arrives as one firm knock and a brief burst. The six-second exhale is a ramp from slow to fast.
Silence between the inhales
The gap before the second inhale is deliberate. Run straight together, the two inhales read as one long buzz; separated by silence, the second one registers as its own breath.
A drawn sigh line
If you open your eyes, the watch draws the breath as two climbs and one long decline, with a dot that marks where you are in the breath.
Two to eight minutes
Sessions run for 2, 4, 6 or 8 minutes, with 4 as the default, on Apple Watch and Wear OS. It sits in the Breathe section alongside Box, 4-7-8 and Extended Exhale.
HRV after, not during
When the session ends, Vayu reads the HRV (SDNN) your watch recorded and uses it to shape the next session. The pace stays at 3-1-6 throughout.
How every phase feels on the wrist, and why HRV is read after the session rather than during it, is explained on the haptic breathing page.
Frequently asked questions
How long should I do Cyclic Sighing each day?
The Stanford trial used five minutes a day for a month. Two minutes is a reasonable start. Vayu offers 2, 4, 6 and 8 minute sessions.
Should I exhale through my nose or mouth?
The trial protocol used a long exhale through the mouth, which makes it easier to keep slow and complete. Both inhales are through the nose.
Is Cyclic Sighing good for sleep?
The trial measured daytime mood and physiological arousal, not sleep, so there is no direct evidence yet. A slow, exhale-led pattern is a reasonable choice at bedtime; 4-7-8 and Extended Exhale are common alternatives.
What is the difference between Cyclic Sighing and box breathing?
Box breathing uses four equal phases, including two holds. Cyclic Sighing has no holds and an exhale much longer than the inhale. Both were tested in the same trial; Cyclic Sighing improved mood the most.
Does Vayu read my HRV during Cyclic Sighing?
No. The watch guides each breath with haptics during the session. Afterwards Vayu reads the HRV (SDNN) your watch recorded and uses it to shape your next session.
Feel the rhythm instead of counting it
Vayu is free to start on iPhone and Android, with the watch app for Apple Watch and Wear OS.
Download VayuOther breathing techniques
One page per technique. The full list with patterns is on the pranayama and breathing techniques hub.
- Box breathing (4-4-4-4)Four equal phases of four seconds: inhale, hold, exhale, hold. A steady, structured reset for focus under pressure.
- 4-7-8 breathing (4-7-8)Inhale for 4, hold for 7, exhale for 8. A long hold and a longer exhale, most often used to wind down before sleep.
- Extended Exhale (3-2-6-2)An exhale twice as long as the inhale, with short pauses. Vayu paces it 3-2-6-2 for calm without long holds.
- Coherent breathing (5 to 6 breaths per minute)Slow, even breathing at about 5 to 6 breaths a minute, the range where heart rate variability responds most.
- Anulom Vilom (4-2-6-2)Breathing through one nostril at a time, alternating sides. Vayu paces it 4-2-6-2, or 2-1-3-1 on the fast setting.
- Bhastrika (4-2-4-2)Full, forceful breaths in and out through the nose. Vayu paces it as deliberate rounds, 4-2-4-2 by default.
- Kapalbhati (60 exhales per minute (normal speed))Short, sharp exhales driven by the belly, with passive inhales between them. Vayu paces one exhale per second by default.
Sources
- Balban et al. 2023, Cell Reports Medicine: brief structured respiration practices enhance mood and reduce physiological arousal. Randomised controlled trial of 5 minutes a day for a month: cyclic sighing, box breathing and cyclic hyperventilation against mindfulness meditation
- Van Diest et al. 2014, Applied Psychophysiology and Biofeedback: inhalation/exhalation ratio modulates the effect of slow breathing on heart rate variability and relaxation. A longer exhale than inhale raised self-reported relaxation, and at 6 breaths a minute raised high-frequency HRV
- Vlemincx et al. 2010, Biological Psychology: respiratory variability preceding and following sighs, a resetter hypothesis. Spontaneous sighs were followed by more structured breathing variability
- Laborde et al. 2022, Neuroscience and Biobehavioral Reviews: effects of voluntary slow breathing on heart rate and heart rate variability, a systematic review and meta-analysis. Voluntary slow breathing raised vagally mediated HRV during the session, straight after it, and after multi-session programmes
