Humming and nitric oxide in the nose

Author: Raymond Hackland · Last reviewed: 18 October 2026 · Reading time: about 6 minutes

In short

• What this is: Your sinuses make a gas called nitric oxide (NO). When you hum with your mouth closed, the vibrating air helps flush that gas out of the sinuses into the nose, where it can be measured.
• What the evidence says: Small laboratory studies from one research network consistently found that humming raises nasal NO for a short time, around 15-fold in the first study; any health benefit of this has not been established.
• What it means for your practice: Humming is a pleasant, gentle way to explore breath and vibration. It is not a technique to prevent or treat anything, and the effect is a brief flush rather than a lasting increase.

What tradition says

This section describes tradition, not science. Humming and closed-mouth toning appear in many breathing and meditation traditions around the world. In the Chinese Qigong tradition, Liu Zi Jue, the Six Healing Sounds, works with long, voiced or whispered exhalations, each paired with an organ in traditional theory; five of them are also paired with an emotion, while the triple-burner sound, xi, has no classical emotion (in my own practice I work with it as a movement “from fragmented to harmony”). These traditions developed long before anyone could measure gases in the nose, and their teachings are not based on nitric oxide. The research below is a separate, modern story that happens to touch on similar ground.

What science says

Where the nitric oxide comes from. In 1995, researchers at the Karolinska Institute in Stockholm reported that the lining of the human paranasal sinuses (the air-filled cavities around the nose) produces nitric oxide continuously, and that sinus air contains it in very high concentrations [1]. The authors suggested, based on the known properties of NO, that it may help keep the sinuses free of bacteria. That was a hypothesis about normal physiology, not a finding about any treatment.

The same group later reported that air from the nose, carrying this NO, reaches the lungs when we breathe in through the nose. In a small study, skin oxygen readings in six of eight healthy volunteers were about 10% higher during nasal breathing than during mouth breathing [2]. This is one reason nasal breathing interests researchers, though it was a small, early study.

The humming finding. In 2002, Eddie Weitzberg and Jon Lundberg tested a simple idea: if the sinuses store NO behind small openings (the ostia), would the vibrating airflow of humming help ventilate them? Ten healthy volunteers breathed out through the nose, either quietly or while humming, at a fixed flow rate. Nasal NO was 15 times higher during humming than during quiet exhalation [3]. A physical model of a nose and sinus showed the same thing: oscillating airflow dramatically increased gas exchange between the two cavities.

What happens in more detail. A follow-up study, also in ten healthy people, found that a single hum produces a large peak of NO that then declines [4]. When people hummed several times in a row, the peak got smaller each time, and it fully recovered only after about three minutes of silence. Blocking NO production in the nasal lining with a drug did not change the humming peak. The researchers concluded that humming causes rapid gas exchange with the sinuses: it releases NO that has already built up there. The size of the sinus openings mattered most, and the pitch of the hum also played a role.

Another study measured NO after five hums in a row. In 18 healthy volunteers, nasal NO during quiet breathing afterwards was on average 16% lower than before [5]. The sinuses had been partly emptied. Acoustic modelling at KTH in Stockholm later explained the mechanism: sound pressure in the nasal cavity makes the air in the sinus opening vibrate back and forth, pumping NO-rich air out [6].

What researchers use it for. The main practical use so far is diagnostic. In 59 people with allergic rhinitis, those whose NO did not rise when humming were much more likely to show signs of blocked sinus openings on endoscopy (9 of 11, compared with 1 of 22 who did show a rise) [7]. A 2013 review discussed humming during nasal NO measurement as a possible clinical tool, while noting that different measuring methods and other confounding factors still make it hard to use [8].

How strong is this evidence? The humming effect itself has been measured repeatedly and is physically well explained. But the studies are small (10 to 59 people), most come from one closely connected group of Swedish and Italian researchers, and they measure gas levels, not health outcomes. That is why this article carries the 🟡 Early evidence label.

Where popular claims go beyond the evidence

You may read online that humming “boosts nitric oxide” and therefore protects against colds, clears sinus problems, or strengthens the immune system. The research does not show this:

• It is a release, not a boost in production. The studies show that humming flushes out NO already stored in the sinuses. Repeated humming empties the store, which then needs minutes to refill [4, 5].
• Gas levels are not health outcomes. No study cited here tested whether humming prevents or shortens any illness.
• One case is not evidence. A frequently shared 2006 paper describes a single person with chronic sinus symptoms who reported improvement after long daily humming sessions [9]. It appeared in a journal for hypotheses, had no comparison group, and cannot show cause and effect. Its author presented it as a hypothesis to be tested.
• Lab properties are not personal effects. NO is known to inhibit bacteria, which is why researchers suspect it helps keep healthy sinuses clean [1]. It does not follow that humming for a few minutes changes your risk of infection.

The honest summary: humming does something real and measurable in the nose. Whether that matters for health is an open question.

How this relates to the Six Healing Sounds, Qigong and neigong

Label for this section: Early evidence (the humming findings) · Tradition only (Qigong and neigong concepts).

The connection is real but indirect. The studies measured nasal humming: mouth closed, air going out through the nose [3, 4]. In the Liu Zi Jue forms we know, all six sounds are breathed out through the mouth, so the nitric oxide findings do not automatically apply to them. None of the studies cited here tested Liu Zi Jue, Qigong or neigong.

Qigong and neigong (“internal work”) traditions value slow, quiet breathing and attention to sensations inside the body, and Liu Zi Jue pairs each sound with an organ in traditional theory, and most of them with an emotion as well. These are traditional concepts with their own history, not findings about gases in the nose. Saying that humming “moves qi”, or that nitric oxide “is” qi, would mix two different kinds of explanation. At most it is a metaphor.

What the two share is sound carried on a long, slow exhalation, and an interest in how vibration feels in the face, head and chest. Resonance Heritage Qi is a personal, music-assisted practice inspired by Liu Zi Jue: connected to it, not a replacement for the traditional form or for study with a teacher of that tradition. Some practitioners like to add a soft, closed-mouth hum between sounds as a moment of resonance and rest. If you do, enjoy it for what it is, without expecting a health effect.

Try it gently (optional)

1. Sit comfortably and breathe in quietly through your nose.
2. Close your lips and breathe out slowly on a soft, low “mmm”, at a comfortable pitch and volume.
3. Notice where you feel the vibration: lips, nose, cheeks, forehead, chest.
4. Rest with a few quiet breaths, then repeat three to five times.

Never force the breath. If you feel dizzy, light-headed or uncomfortable, stop and breathe normally. If your nose is blocked, humming through the nose may not be comfortable; there is no need to push.

Sources

1. Lundberg JO, Farkas-Szallasi T, Weitzberg E, Rinder J, Lidholm J, Änggård A, Hökfelt T, Lundberg JM, Alving K, 1995. High nitric oxide production in human paranasal sinuses. Nature Medicine 1(4):370–373. https://doi.org/10.1038/nm0495-370
2. Lundberg JO, Settergren G, Gelinder S, Lundberg JM, Alving K, Weitzberg E, 1996. Inhalation of nasally derived nitric oxide modulates pulmonary function in humans. Acta Physiologica Scandinavica 158(4):343–347. https://doi.org/10.1046/j.1365-201X.1996.557321000.x
3. Weitzberg E, Lundberg JO, 2002. Humming greatly increases nasal nitric oxide. American Journal of Respiratory and Critical Care Medicine 166(2):144–145. https://doi.org/10.1164/rccm.200202-138BC
4. Maniscalco M, Weitzberg E, Sundberg J, Sofia M, Lundberg JO, 2003. Assessment of nasal and sinus nitric oxide output using single-breath humming exhalations. European Respiratory Journal 22(2):323–329. https://doi.org/10.1183/09031936.03.00017903
5. Maniscalco M, Sofia M, Weitzberg E, Carratù L, Lundberg JO, 2003. Nasal nitric oxide measurements before and after repeated humming maneuvers. European Journal of Clinical Investigation 33(12):1090–1094. https://doi.org/10.1111/j.1365-2362.2003.01277.x
6. Granqvist S, Sundberg J, Lundberg JO, Weitzberg E, 2006. Paranasal sinus ventilation by humming. Journal of the Acoustical Society of America 119(5 Pt 1):2611–2617. https://doi.org/10.1121/1.2188887
7. Maniscalco M, Sofia M, Weitzberg E, De Laurentiis G, Stanziola A, Rossillo V, Lundberg JO, 2004. Humming-induced release of nasal nitric oxide for assessment of sinus obstruction in allergic rhinitis: pilot study. European Journal of Clinical Investigation 34(8):555–560. https://doi.org/10.1111/j.1365-2362.2004.01384.x
8. Maniscalco M, Pelaia G, Sofia M, 2013. Exhaled nasal nitric oxide during humming: potential clinical tool in sinonasal disease? Biomarkers in Medicine 7(2):261–266. https://doi.org/10.2217/bmm.13.11
9. Eby GA, 2006. Strong humming for one hour daily to terminate chronic rhinosinusitis in four days: a case report and hypothesis for action by stimulation of endogenous nasal nitric oxide production. Medical Hypotheses 66(4):851–854. https://doi.org/10.1016/j.mehy.2005.11.035

Source quality note: The humming studies are small laboratory and pilot studies (10 to 59 participants), almost all from one connected Swedish–Italian research network, with no large independent replication. They measure nitric oxide levels, not health outcomes. Source [9] is a single uncontrolled case report and is cited only to show why it is not evidence of benefit.