Cyclic sighing:
the protocol and the numbers
Cyclic sighing is the breathing pattern that came out ahead in a 2023 Stanford trial of 108 people. It takes five minutes and needs nothing. Here is exactly how the participants were told to do it, what changed over a month, and what the trial could not tell anyone.
How to do it
These are the instructions the trial gave its participants, in plain words.1
Sit in a chair, or lie down if you prefer. Set a timer for five minutes. Inhale slowly through the nose. When your lungs feel full, inhale again, a shorter top-up, to fill them completely. Then exhale slowly and fully, ideally through the mouth, until the lungs are empty. Repeat until the timer rings.
The paper gives no seconds for any phase, so any pacer you use is choosing them for you. Ours is here: a five-minute cyclic sighing pacer, with the exhale length adjustable.
What the study found
108 adults were randomized to one of four daily five-minute practices for 28 days: cyclic sighing, box breathing, cyclic hyperventilation with retention, or mindfulness meditation. They rated mood and state anxiety before and after each session and wore a wrist strap that logged resting heart rate, breathing rate, heart rate variability and sleep.1
Mood. The average per-session rise in positive affect was 1.89 points for cyclic sighing and 1.22 for mindfulness meditation, on a 10 to 50 scale. The three breathing groups together averaged 1.91. Mindfulness on its own did not quite reach significance (p = 0.06).
Anxiety. It fell in every group after every session, and the groups did not differ: −3.85 for cyclic sighing, −3.95 for mindfulness.
Breathing rate. Over the month, the day-to-day resting breathing rate fell more in the breathing groups than in the meditators, and cyclic sighing was significant on its own. Resting heart rate, heart rate variability and sleep did not change in any group.
How much people actually did. About 18 to 20 of the 28 days, around six minutes a day. Adherence did not differ between groups.
What it could not show
There was no group that did nothing, so the trial compares four practices with each other, not with skipping it. The mood and anxiety numbers are self-reported. The idea that a long exhale calms you by way of the parasympathetic system is the authors' hypothesis, not something the trial measured. And it is one trial. The larger picture, rate, exhale and belly across the literature, is more modest than any single headline.
Where quiettime fits
quiettime does not pace you. It is a silent timer for a sit, and with the camera on it reads what your breathing actually did: breaths per minute and how long each inhale and exhale ran, eyes closed, nothing worn, nothing recorded. If you practice cyclic sighing for five minutes and then sit, you can see whether the slower rate carried into the sit. How it reads your breath.
How many times a day should I do cyclic sighing?
In the trial, once a day for five minutes, for 28 days. Participants managed about 18 to 20 of the days.
Nose or mouth?
The participants were told that ideally both inhales go through the nose and the exhale goes through the mouth.
How long should each breath be?
The paper does not say. It describes the shape of the breath, two inhales and one long full exhale, and leaves the timing to the person. Any timer's seconds are the timer's choice.
Is cyclic sighing better than meditation?
For per-session mood in that trial, yes: 1.89 versus 1.22 points. For anxiety, the two did about equally well. Breathing rate fell more over the month in the breathing groups.
Who came up with it?
The physiological sigh, a double inhale and a long exhale, is a natural reflex. The 2023 trial from Stanford, with Andrew Huberman and David Spiegel among the authors, tested it as a daily five-minute practice and named the practice cyclic sighing.
How quiettime reads your breath →
Sources
- Balban MY, et al. Brief structured respiration practices enhance mood and reduce physiological arousal. Cell Reports Medicine, 2023 (n=108).