Physiological sigh timer (cyclic sighing)

How to do the physiological sigh

1. Inhale through your nose until your lungs feel nearly full, about 80%.
2. Take a second, short inhale through the nose to top them up completely. The music crossfades and the orb fills to the edge.
3. Exhale slowly through your mouth until your lungs are empty. Make the exhale about twice as long as both inhales together.
4. Repeat for about five minutes, or do one to three sighs whenever you notice stress building.

What happens in your body

Sighing is a built-in reflex. We all sigh spontaneously every few minutes, more often under stress. A basic job of a sigh is to re-inflate the tiny air sacs (alveoli) in the lungs that slowly collapse. Research in mice has traced this reflex to a small cluster of neurons in the brainstem.

The long exhale does the calming. Your heart naturally speeds up a little as you breathe in and slows as you breathe out. This normal rhythm is called respiratory sinus arrhythmia. Weighting each breath towards the out-breath is one reason cyclic sighing feels settling. In an experiment with 30 people, making the out-breath longer than the in-breath helped them feel more relaxed than simply breathing slowly.

What the study found

In a one-month Stanford study, 108 adults did five minutes a day of cyclic sighing, box breathing, cyclic hyperventilation or mindfulness meditation. Cyclic sighing was the only technique that lifted daily positive mood significantly more than mindfulness, and it lowered resting breathing rate the most.

Keep it in proportion: this is one exploratory study with small groups. Resting heart rate, heart-rate variability and sleep didn't change measurably in any group. Stanford neuroscientist Andrew Huberman, one of the authors, has popularised the technique as a fast way to calm down in real time.

Want the bigger picture? Read how breathing affects your body and mind: the heart, the nervous system, blood pressure and mood, with illustrations and 20+ studies.

Make it yours in Breathcharge

Tap the top-up on the timeline to set its length (0.3 to 3 s works well), or remove it. For a slower version, try the Slow sigh preset: 4 s in, a 1.2 s top-up, 8 s out and a 1 s rest. Increase Fade-out before each switch in Sound settings if you want more warning before the exhale.

Breathing safely

The slow patterns here are gentle, but holds and deep inhales can make you light-headed. Stop and breathe normally if you feel dizzy. Never practise breath holds in or near water, or while driving. If you are pregnant, or have a heart, lung or seizure condition or panic disorder, check with a clinician first. Breathing exercises can complement medical care but don't replace it.