Left Nostril and Right Nostril Breathing
In and out through one nostril. The two quietest techniques in the app, the difference between them, and where the evidence is weak.
5 min read
Close one nostril lightly with a finger and breathe in and out through the other only. You don't switch sides — the same nostril stays open throughout.
There are two separate techniques, and the difference between them is in the rhythm.
Left Nostril: four in, six out
The exhale is longer than the inhale. A long exhale helps the heart slow, so this technique sits on the calming side.
Suited to the evening and before sleep.
Right Nostril: four in, four out
The inhale and exhale are equal. The calming effect is deliberately left out: this technique is for keeping alertness up.
For the morning, or the dullness of the early afternoon. Done late in the day it can make falling asleep harder — the app reminds you of this at night.
Where the evidence stands
The studies on these two techniques measured single-nostril practice and reported different effects for the right and the left.
The evidence is weak. Participant numbers are small and the results are waiting to be repeated. "The right nostril wakes you up, the left calms you down" is the best estimate we have, not a settled finding.
The second values — why four, why six — aren't in the studies either. They were chosen from the slow-breathing literature.
The suggested length in the app does come from the studies: the practice that was measured is twenty-seven breath cycles, and the suggested length is built from that. Going shorter in these techniques isn't "doing a bit less", it is not doing the thing that was measured.
How it differs from the classical form
The traditional form alternates: in through one nostril, out through the other. That is in the app too, called Alternate Nostril.
The single-nostril form here is simpler, and it is the form the source studies measured. In the app they unlock before Alternate Nostril — getting used to one nostril makes the four-step alternating form easier.
How to do it
Sit comfortably. Press lightly on the side of the nostril you are closing — no force is needed to block it.
Breathe in slowly through the open nostril for four seconds.
Breathe out through the same nostril: six seconds on the left side, four seconds on the right. Don't release your finger.
Common mistakes
Switching nostrils. The two nostrils don't alternate in this technique. The same one stays open.
Pressing hard enough to block the nose. Touching the side lightly is enough.
Drawing in fast by force. Air passes slowly through one nostril; don't rush.
How the app measures it
These are the quietest techniques in the app. Both the inhale and the exhale are very low.
The app knows this and uses its most sensitive thresholds for these two. Even so, not being heard is normal — you need to bring the device a little closer.
Don't force the breath to make it audible. A forced single-nostril breath both spoils the technique and lowers the measurement.
Who should take care
If your nose is blocked, don't force it — pick another technique. No other known risk.
Sources
- Raghuraj & Telles (2008), Applied Psychophysiology and Biofeedback — a study comparing right, left and alternate nostril breathing; twenty-one participants. PubMed
- Telles et al. (1994), Indian Journal of Physiology and Pharmacology — one of the early studies of single-nostril practice. Search PubMed