What is a physiological sigh?
A physiological sigh is a double inhale followed by a long exhale: breathe in through your nose, take a second short sip of air on top, then breathe out slowly through your mouth. Repeating it for a few minutes is called cyclic sighing. In a 2023 Stanford study, five minutes a day lifted mood more than mindfulness meditation.
You already do this without thinking. People naturally sigh every few minutes, and you have probably noticed a big involuntary sigh at the end of a cry or after a stressful moment passes. The physiological sigh simply does it on purpose.
This timer uses a 3 second inhale, a 1 second top-up and a 6 second exhale, ten seconds per breath. Those numbers are a guide rather than a rule: the study did not prescribe exact seconds. What matters is that the second inhale is short and the exhale is clearly the longest part.
How to do it, step by step
- Breathe in through your nose. Take a fairly full breath in through your nose as the circle grows.
- Sip in a little more. Without breathing out, take a second short inhale through your nose to top your lungs up.
- Long breath out. Breathe out slowly and fully through your mouth, as if sighing, as the circle shrinks.
- Repeat. Do one or two sighs for a quick reset, or keep repeating for a few minutes for cyclic sighing.
- Return to normal breathing. When you finish, let your breath find its own rhythm and notice how you feel.
If you cannot breathe through your nose, both inhales through the mouth is fine. The study participants were told nose in, mouth out was ideal but not required.
When to use it
- In the moment: one to three sighs when you feel a spike of stress. It is quick enough to do between messages.
- As a five minute daily practice: the format used in the Stanford study.
- When you feel you cannot get a full breath: the top-up inhale often helps that tight, unfinished feeling.
What the research says
The best known study is a 2023 randomized trial from Stanford, published in Cell Reports Medicine. 108 adults spent five minutes a day for 28 days on one of three breathing practices (cyclic sighing, box breathing, or cyclic hyperventilation with retention) or on mindfulness meditation. Every group reported improvements in mood and anxiety. The cyclic sighing group had the largest increase in positive mood, significantly more than the meditation group, and it was the only group whose resting breathing rate dropped significantly compared with meditation (Balban et al., 2023).
It helps to read that result carefully. The comparison was against mindfulness meditation, which also helped, rather than against doing nothing. Groups were fairly small, the study ran remotely, there were no significant changes in heart rate variability or resting heart rate, and the authors describe it as exploratory and call for a larger trial.
The wider picture is consistent with it. A 2018 systematic review linked slow breathing with feeling more relaxed and less anxious (Zaccaro et al., 2018), and cyclic sighing at this timer's pace works out to six breaths a minute.
Who should go gently
Keep the second inhale small. Over-filling your lungs, or sighing quickly over and over, can leave you lightheaded. If you feel dizzy or tingly, slow down, make the breaths smaller, or stop and breathe normally.
If you are pregnant, have a heart or lung condition such as asthma or COPD, or have a history of panic attacks, go gently and stop if anything feels uncomfortable. This is a general wellbeing tool, not medical advice or treatment. If you have a health condition or concerns, check with your doctor before starting a new breathing practice.
Frequently asked questions
What is the difference between a physiological sigh and cyclic sighing?
A physiological sigh is a single double inhale followed by a long exhale. Cyclic sighing is doing that repeatedly, usually for a few minutes, as in the 2023 Stanford study that used five minutes a day.
How many physiological sighs should I do?
One to three sighs is enough for a quick reset in the moment. For a daily practice, try cyclic sighing for one to five minutes.
Do I breathe in through my nose or my mouth?
Ideally both inhales go through your nose and the exhale goes out through your mouth. If your nose is blocked, breathing in through your mouth is fine.
Why take two breaths in?
The short second inhale tops your lungs up after the first one, which many people find relieves that tight, can't quite get a full breath feeling. It also sets up a long, slow exhale, which is the part that feels most calming.
Is cyclic sighing better than meditation?
In one 2023 study it improved positive mood more than mindfulness meditation over a month, though both helped. It was a single, fairly small study, so the honest answer is that both are worth trying and you can pick what you will actually do.
From the makers of this timer
Want this to show up mid-scroll?
DeRot pauses your scroll and walks you through a breath like this one. Sixty seconds later your shoulders have dropped, your head feels clearer, and you carry on, calmer. No willpower needed, just a breather.
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More free breathing tools
Calm breathing 4-6
In for 4, out for 6. About six breaths a minute, and DeRot's everyday Calm pattern.
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Four equal sides: in, hold, out, hold. Steady and easy to remember.
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A long hold and a longer exhale. A favorite for winding down at night.
Custom timer
Set your own inhale, hold and exhale, from 1 to 12 seconds each.
Sources
- Balban MY, et al. (2023). Brief structured respiration practices enhance mood and reduce physiological arousal. Cell Reports Medicine, 100895. doi.org/10.1016/j.xcrm.2022.100895
- Zaccaro A, Piarulli A, Laurino M, et al. (2018). How breath-control can change your life: a systematic review on psycho-physiological correlates of slow breathing. Frontiers in Human Neuroscience, 12, 353. doi.org/10.3389/fnhum.2018.00353