Physiological Sigh (Cyclic Sighing)

How to do it

1. Sit, stand or lie down. Eyes open is fine, so you can do it in the middle of a task.
2. Breathe in through your nose: a comfortable, full breath, not a gasp.
3. Without breathing out, sip in a second, shorter breath through your nose to top up your lungs.
4. Breathe out slowly through your mouth until your lungs feel empty. Make the exhale longer than both inhales together.
5. In the moment, one or two sighs are enough. As a daily practice, repeat at an easy pace for 5 minutes.
6. Finish on an exhale and let your breathing return to its own rhythm.

Benefits

• Calmer in one or two breaths

  The long exhale is the part that settles you. One or two deep sighs already take the edge off^[5].

• A better mood with daily practice

  In a month-long Stanford trial, 5 minutes of cyclic sighing a day lifted positive mood more than mindfulness meditation did^[1].

• Slower breathing at rest

  The same trial found the largest drop in resting breathing rate in the cyclic sighing group^[1].

• Use it anywhere, eyes open

  No posture, no equipment and no need to stop what you're doing. It fits at your desk, in a waiting room or before a call.

What the research says

The deliberate practice was tested in a 2023 Stanford trial. 108 adults were randomly assigned to 5 minutes a day, for 28 days, of cyclic sighing, box breathing, cyclic hyperventilation with breath holds, or mindfulness meditation^[1]. Cyclic sighing raised daily positive mood significantly more than meditation, and the benefit grew over the month^[1][5]. It also gave the largest drop in resting respiratory rate^[1]. Anxiety and negative mood fell in all four groups, with no significant difference between them, and heart rate and heart rate variability did not change significantly^[1].

The trial measured a month of daily practice, not how quickly a single sigh calms you in the moment^[1]. In Stanford's write-up of the trial, David Spiegel suggests about 5 minutes of sighing, and the article notes that you may feel calmer after just one or two^[5].

The sigh reflex itself is mapped in mice. Li and colleagues found small groups of brainstem neurons that release the peptides neuromedin B and gastrin-releasing peptide onto the preBötzinger complex, the breathing rhythm generator; blocking both receptors abolished sighing^[2]. Sighs happen on their own every few minutes and reinflate the lungs' tiny air sacs, the alveoli^[2].

In people, Vlemincx and colleagues propose that a sigh resets breathing that has turned irregular, and that this reset brings relief^[3]. In one of their lab studies, an instructed deep breath raised people's sense of relief, and a spontaneous sigh lowered forehead-muscle tension in people with high anxiety sensitivity^[4].

Tips

• Don't breathe out between the two inhales. Stack the second sip right on top of the first.
• Keep the second inhale small: a comfortable first breath, then just enough to top up.
• Slow the exhale until it clearly outlasts both inhales together.
• Keep the pace easy. This is not fast breathing; if you feel lightheaded, slow down.
• Nose blocked? Do the whole pattern through your mouth.

Related exercises

• Prolonged ExhalationBreathe in softly, breathe out twice as long. No holds, just two numbers to follow.
• Box BreathingIn, hold, out, hold, four seconds each. A steady breath you can take anywhere.
• VOO BreathAn easy breath in, then one long, low "voo" that you feel in your chest and belly.