Physiological sigh timer (cyclic sighing)
The physiological sigh is a double inhale and a long, slow exhale. It is the breath your body already does when you sob or before you fall asleep. Doing it on purpose is one of the quicker ways to settle, and repeating it for a few minutes is what researchers call cyclic sighing.
- Breathe in 3s
- Breathe out 6s
Take it with you in the app
This tool runs in your browser. Want it on your phone, with voice cues, background timing and a real alarm? Open the same tool in NanoTimer.
Open on your phoneOpens the right tab in NanoTimer on your iPhone.
Download on theApp StoreLink coming soon
How it works
- As the circle grows, breathe in through your nose, then add a second short sip of air on top so your lungs are fully full.
- As the circle shrinks, let a long, slow breath out through your mouth.
- One or two rounds can take the edge off a stressful moment. For a fuller reset, keep going for about five minutes.
- Sit or lie down and keep it gentle. This is slow breathing, not hyperventilation.
Frequently asked questions
- Does the physiological sigh really work?
- There is real evidence. A 2023 Stanford trial (Balban and colleagues, in Cell Reports Medicine) had people do five minutes a day of one breathing practice for a month. Cyclic sighing, which is repeated physiological sighs, improved mood the most and lowered resting breathing rate more than box breathing, cyclic hyperventilation or mindfulness meditation.
- Why the double inhale?
- The second short inhale is thought to reopen collapsed air sacs in the lungs, so the long exhale can offload more carbon dioxide. That is the mechanism researchers point to for why a single sigh can settle you quickly, though the exact reasons are still being studied.
- What is the difference between a physiological sigh and cyclic sighing?
- A physiological sigh is one breath: double inhale, long exhale. Cyclic sighing is doing it repeatedly, usually for around five minutes, which is what the Stanford study tested. This timer runs the repeated version.
- Can I do this in the app?
- Yes. The NanoTimer app has a dedicated Breathe section: guided, adjustable breathing patterns, free.