Alternate nostril breathing: what it is, and what the research actually says

Close-up of a person's nose and mouth at rest, black and white

Of all the breathing techniques, alternate nostril breathing is the one a nasal inhaler suits most naturally: you are already working one nostril at a time. It is also the one whose popular explanation falls apart fastest under inspection. Both things are worth knowing before you try it, so here is the technique, the real physiology, and the myth.

How to do it

  1. Rest your right thumb beside your right nostril and your ring finger beside your left.
  2. Close the right nostril with your thumb. Breathe in slowly through the left.
  3. Close the left with your ring finger, release the right, and breathe out through the right.
  4. Breathe in through the right.
  5. Close the right, release the left, breathe out through the left.
  6. That is one round. Continue for three to five minutes, unhurried, no straining.

With an inhaler, hold it below whichever nostril is open on the in-breath. Traditional instructions often add breath retention between the in and out. We would leave that out, for reasons in the safety note at the end.

The part that is true: your nostrils really do take turns

The nasal cycle is real, well documented, and slightly strange. Erectile tissue in your nose swells on one side and shrinks on the other under autonomic control, so most of your airflow runs through one nostril at a time, then switches. You have been doing it all day without noticing.

Researchers recorded airflow continuously over 24 hours in 33 people and found waking cycles averaging about 2 hours and sleeping cycles about 4.5 hours.1 The important detail is buried in the variation: the standard deviation was ±1.7 hours on a 2-hour average, and the authors describe the cycle as “highly variable within and across subjects.” It is a real rhythm, not a clock. Anyone telling you your nostrils switch on a reliable schedule you can plan around has over-tidied the data.

The part that is not true: hemisphere balancing

The claim you will read everywhere is that because each nostril connects to the opposite side of the brain, alternating between them balances the two hemispheres. Left nostril for calm and the right brain, right nostril for alertness and the left brain.

This traces back to a single small study from 1983 that reported a correlation between EEG activity in one hemisphere and airflow in the opposite nostril.2 It is a real paper. It has also been directly tested twice with modern equipment, and it did not hold up.

A 2022 study put 30 people through unilateral nostril breathing with 64-channel EEG. Breathing through one nostril did change brain activity, which is interesting in itself. But the authors state plainly that the expected contralateral bias in hemispheric activity was not supported; the changes were largely bilateral, and better described as arousal versus relaxation than as hemispheric switching.3 A 2024 study combining airflow measurement with structural and functional MRI in 35 people likewise found that nostril dominance produced no significant lateralisation.4

So the mechanism most commonly given for this practice is, as far as current evidence goes, wrong. That does not make the practice worthless. It makes the explanation worthless.

What about the outcomes?

Anxiety: the best-designed test was null. Researchers randomised 30 yoga-naive medical students to either 15 minutes of alternate nostril breathing or quiet rest, then put them through a simulated public speaking task. Anxiety scores were numerically lower in the breathing group but the difference was not statistically significant, and the authors concluded the practice did not produce a significant decrease in induced anxiety.5 Small and underpowered, so treat it as unresolved rather than disproven, but it is the most direct evidence available and it is not encouraging.

Blood pressure: promising numbers we would not quote. A 2024 meta-analysis pooled six trials and reported reductions of roughly 7 mmHg systolic and 5 mmHg diastolic. We are not going to repeat those as reliable figures, because the same analysis reports heterogeneity above 90%, meaning the trials disagreed with each other almost completely, alongside implausibly narrow confidence intervals. The authors themselves say most studies were not double-blinded and call for higher-quality trials.6 Something may be there. The current estimate is not trustworthy.

So should you bother?

Honestly, yes, if you enjoy it, and with adjusted expectations. Here is what we think it is actually doing:

  • It slows you down. The mechanics force a long, deliberate rhythm, and slow breathing is the part of this whole field with the most support behind it.7
  • It occupies your hands and your counting. The sequence is fiddly enough to hold attention, which is a genuine advantage when your mind is racing.
  • It guarantees nasal breathing, one nostril at a time, which is where an inhaler fits perfectly.

What it is probably not doing is balancing your hemispheres or rebalancing your nervous system through some nostril-specific channel. Treat it as a well-designed ritual for slowing down rather than a mechanism, and it holds up fine.

Safety note

Skip the breath retention that traditional versions include, especially if you are new to this. A 2025 review of pranayama trials found adverse events were more common with fast and forceful techniques than gentle slow ones, and noted that harms are barely reported in this literature at all.8 Be particularly careful with holds if you are pregnant, have heart or blood pressure conditions, epilepsy, a respiratory condition, or a history of panic attacks: breath holds manipulate the same signals researchers use deliberately to provoke panic in laboratory settings.9 Gentle, unforced, no holds is the version to start with. Stop if you feel dizzy.

If you want to try it with something in the tube, our Calm Blend suits a slow evening round, and the $2 sample is the cheap way to test the format.

This article is general information, not medical advice. If anxious feelings are frequent, intense or getting in the way of daily life, please talk to your GP or a mental health professional. In Australia you can also call Lifeline on 13 11 14 or Beyond Blue on 1300 22 4636.

References

  1. Kahana-Zweig R, Geva-Sagiv M, Weissbrod A, Secundo L, Soroker N, Sobel N. Measuring and characterizing the human nasal cycle. PLoS One. 2016;11(10):e0162918. PubMed
  2. Werntz DA, Bickford RG, Bloom FE, Shannahoff-Khalsa DS. Alternating cerebral hemispheric activity and the lateralization of autonomic nervous function. Human Neurobiology. 1983;2(1):39–43. PubMed
  3. Niazi IK, Navid MS, Bartley J, et al. EEG signatures change during unilateral Yogi nasal breathing. Scientific Reports. 2022;12:520. PMC
  4. Thaploo D, et al. Lateralisation of nasal cycle is not reflected in the olfactory bulb volumes and cerebral activations. European Journal of Neuroscience. 2024. Journal
  5. Kamath A, Urval RP, Shenoy AK. Effect of alternate nostril breathing exercise on experimentally induced anxiety in healthy volunteers using the simulated public speaking model: a randomized controlled pilot study. BioMed Research International. 2017;2017:2450670. PMC
  6. Nam TG, Jeong H, Kim KH, Jang I. Effectiveness of alternative nostril breathing on blood pressure: a systematic review and meta-analysis of randomized controlled trials. Complementary Medicine Research. 2024;31(5):449–460. PubMed
  7. Zaccaro A, Piarulli A, Laurino M, et al. How breath-control can change your life: a systematic review on psycho-physiological correlates of slow breathing. Frontiers in Human Neuroscience. 2018;12:353. PMC
  8. Mütze C, Mitzinger D, Haller H. Effectiveness of pranayama for mental disorders: a systematic review and meta-analysis of randomized controlled trials. Frontiers in Psychiatry. 2025;16:1616996. PMC
  9. Papp LA, Klein DF, Gorman JM. Carbon dioxide hypersensitivity, hyperventilation, and panic disorder. American Journal of Psychiatry. 1993;150(8):1149–1157. PubMed

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