Cyclic sighing (the physiological sigh): how to do it

What is cyclic sighing?

A sigh is not just a sign of frustration. Everyone takes a deeper, double breath every few minutes, which helps reopen tiny air sacs in the lungs that slowly collapse with ordinary breathing. Cyclic sighing borrows that natural pattern: fill your lungs through the nose, top up with a second short sip, then let the air out slowly through your mouth. The long out-breath is the important part.

When should you use it?

As a 5-minute daily practice for stress, or for one to three breaths when you need to calm down quickly, before a meeting or after a scare. It needs no counting, which some people find easier than counted patterns.

What the research shows

In a randomised trial run remotely by Stanford University researchers, 108 healthy adults did 5 minutes a day of one of three breathing exercises (cyclic sighing, box breathing or cyclic hyperventilation with breath-holds) or mindfulness meditation, for a month. Everyone improved on mood and anxiety. The breathing groups together gained more positive mood than the meditation group, and cyclic sighing gave the biggest improvement in positive mood and the largest fall in resting breathing rate.

That is promising, but it is one trial, in healthy volunteers, with mood measured by questionnaire. One of the authors also advised a wearable company, which was disclosed. We grade it weak until other teams repeat it. The broader evidence for breathing exercises and stress and anxiety is stronger.

Common mistakes

• Making the in-breaths huge. Fill comfortably, then top up a little.
• Rushing the out-breath. Let it be the longest part, slow and unforced.
• Doing it fast and continuously. Repeated big breaths at speed can make you dizzy. Keep the pace relaxed.

Make it easier or harder

• Easier: do three sighs, then breathe normally for a minute, then repeat.
• Harder: lengthen the out-breath and build to the full 5 minutes a day.