The Physiological Sigh
You’ve done it thousands of times without thinking. After a long cry, when the shuddery breaths finally slow. As you drift off to sleep. In the quiet moment after something stressful has passed.
That deep, double-breath sigh is built into you. The physiological sigh simply takes something your body already knows how to do, and puts it in your hands.
What is it?
01The physiological sigh is two breaths in through the nose, a full breath and then a short top-up sip, followed by a long, slow breath out through the mouth.
People and many animals sigh naturally, often without noticing. Doing it on purpose, several times in a row, is sometimes called cyclic sighing.
If the name sounds familiar, that’s probably thanks to neuroscientist Andrew Huberman, who has talked about it widely on his podcast, and whose Stanford lab co-led the best-known study of it.
What may it help with?
02The physiological sigh is made for the in-between moments:
- the minute before a hard conversation
- a wave of panic in the supermarket queue
- lying awake with your heart still racing
- sitting in the car park before walking back into work
It won’t change what’s causing the stress. What it can do is give you a little more room to think about what you need next.
How does it work?
03Your lungs contain millions of tiny air sacs. When we’ve been breathing shallowly for a while, some of them can partly deflate, a bit like a balloon that’s gone soft. The second, shorter in-breath is thought to help open them back up.
The long breath out does the calming work. Slow exhales are linked with a slower heart rate and a shift towards the body’s rest state.
Because it’s so quick, it suits the moments when a longer practice just isn’t possible.
What does the evidence say?
04In a 2023 Stanford study, 108 adults practised five minutes a day for a month. Each was given one of four practices: cyclic sighing, box breathing, a fast breathing pattern or mindfulness meditation.
Everyone tended to feel better after each session. Over the month, the breathing practices lifted mood more than meditation, and cyclic sighing showed the biggest lift in mood and the biggest drop in breathing rate [1].
It’s early research, but for something that takes less than a minute, it’s a lovely one to keep in your pocket.
How to practise
05In through your nose, until your lungs feel comfortably full.
A second, shorter sip of air on top.
Out through your mouth, slow and long, for longer than both breaths in together.
One to three sighs can be enough for a quick reset. For a daily practice, the Stanford study used five minutes. As you go, notice what happens to your shoulders and your jaw.
Considerations
06Ease off if you feel light-headed. A few sighs are plenty. If you feel dizzy or tingly, slow down and return to your normal breathing.
You’ve read about it. Now what can you actually do?
You don’t need to have the perfect plan. Choose the next step that feels most useful for where you are right now.
Always speak with a qualified health professional before starting something new. If you are struggling right now, find immediate support.
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This is educational information. It is not a recommendation that this approach is right for you. Always speak with a qualified health professional.
