How do you do the physiological sigh?

The second breath in is shorter and smaller than the first. The study told people that this is normal. The long breath out is the main part of the exercise. The researchers call it an “exhale-focused” pattern.

How do you do the physiological sigh? The Short Answer

Step	What to do
1	Breathe in slowly through your nose
2	When your lungs feel full, breathe in once more through your nose
3	Breathe out slowly through your mouth until your lungs are empty
Repeat	Do this for 5 minutes, once a day

The Physiological Sigh Breathing Technique, Step by Step

These are the instructions that the study gave to its cyclic sighing group:

1. Sit or lie down. Sit in a chair, or lie down if you prefer.
2. Set a timer for 5 minutes. You need only the 5 minutes.
3. Breathe in slowly. Use your nose if you can.
4. Breathe in once more. When your lungs are full, breathe in again to fill them as much as you can. This second breath is short.
5. Breathe out slowly and fully. Let all the air out, ideally through your mouth.
6. Repeat for 5 minutes. Then go back to normal breathing.

The study did not give a count in seconds for each step. It gave only the order and the instruction to breathe out slowly. The timer on this page uses 2 seconds in, 1 second in, and 6 seconds out. Use the timer on this page to keep the pace, or breathe at a pace that is comfortable for you.

The study asked people to do the exercise once a day, not more. If you feel unwell, stop and breathe normally.

Physiological Sigh and Cyclic Sighing: What the Names Mean

A sigh is a normal part of breathing. Ramirez describes it in a 2014 review as a deep, augmented breath. A normal breath triggers it, and a short pause follows it. The review shows the sigh as a breath with two parts: a normal breath and then a large sigh on top of it.

The review says that sighs expand the lungs to their maximum. This helps to stop the small air sacs in the lungs (alveoli) from slowly collapsing. Adults sigh at regular times without thinking about it. The review also says that sighs can reset the normal variation in breathing.

“Physiological sigh” is the popular name for doing this breath on purpose. The 2023 study does not use that name. It calls the 5-minute exercise “cyclic sighing”, because you repeat the sigh in cycles. The two names describe the same breath.

What the 2023 Study Found

The study compared 3 breathing exercises with mindfulness meditation. It had 108 adults, and most of them came from an undergraduate psychology class at Stanford University. The study was remote. Each person did a 5-minute exercise at home each day for 1 month.

These are the main results:

• Everyone felt better after each session. State anxiety and negative mood went down, and positive mood went up, in all 4 groups.
• Cyclic sighing gave the largest mood increase. The cyclic sighing group had the highest increase in positive mood over the month. The breathing groups together did better than meditation on positive mood.
• Anxiety did not differ. The drop in state anxiety and negative mood was not different between breathing and meditation.
• Breathing at rest got slower. The cyclic sighing group had a larger drop in respiratory rate (breaths per minute at rest) than the meditation group.
• Heart rate and sleep did not change. The study found no significant change in heart rate variability or resting heart rate. Sleep scores did not differ between groups.

The study has limits, and the authors list them. It was an exploratory study, and it was registered after it started. Only 30 people started in the cyclic sighing group. It lasted 4 weeks, with no follow-up. The researchers could not check how closely people followed the instructions at home.

So the physiological sigh is a simple exercise with early, promising results. It is not a proven treatment.

Popular Claims About the Physiological Sigh

Andrew Huberman was the lead contact of the study and recorded the instruction videos. Many claims online come from podcasts, not from the paper.

“One or two sighs calm you down at once.” This claim is popular. The study tested 5 minutes a day for 1 month. It did not test 1 or 2 sighs. We found no primary source for the claim.

“It is the fastest way to reduce stress.” The study did not test speed. Mindfulness meditation reduced state anxiety by a similar amount.

“It improves heart rate variability.” The study found no significant change in heart rate variability.

Safety

The study did not include people with heart disease, glaucoma, a history of seizures, pregnancy or some mental health conditions. If one of these applies to you, talk to a doctor before you start.

Breathe gently. Ramirez writes that a lot of sighing may cause a state of high arousal, and that this could make panic worse. This is a hypothesis, not a tested result. The exercise uses slow, controlled breaths, not fast, repeated sighs.

If you want a calming exercise with no double breath in, the NHS gives a free one. Breathe in gently for a count of 1 to 5, then breathe out for a count of 1 to 5. Do this for at least 5 minutes. Read more in What is coherent breathing?. For another exercise from the same study, read How do you do box breathing?.

How to Practise the Physiological Sigh With Steady

You do not need an app for the physiological sigh. A timer for 5 minutes is enough. Steady is a breathing timer for iPhone and iPad that keeps the pace for you.

Steady does not have a built-in program for the physiological sigh. You must make a Custom Program. Steady has no phase for a second breath in, so use the hold phase for it:

• Custom Program. Set Inhale to 3 seconds, Inhale Hold to 1 second and Exhale to 6 seconds. Set Exhale Hold to 0. During Inhale Hold, take the short second breath in. The app calls this phase a hold, so ignore the word and breathe in. See custom programs.
• Audio and Vibration Cues. A voice or a vibration tells you when to change phase. You can practise with your eyes closed. See cues and ambience.
• Daily Reminders. Set a reminder for your daily 5-minute session. See reminders.
• My Stats. See your total minutes, sessions and streaks. See stats and badges.

Some features need Steady Pro. Steady does not diagnose or treat a condition. It is a timer that helps you practise.

This guide is general information, not medical advice. Talk to a doctor about symptoms.