Potential immune-protective effects of Nitric Oxide and humming

Gentle nasal breathing optimises Nitric Oxide (NO) levels in airways and blood. Humming leads to a 15 to 20-fold increase in NO levels helping to open up airways and kill pathogens.

NO is:

  • produced in the paranasal sinuses and carried into the lungs during nasal breathing
  • known to be broadly antifungal, antiviral and antibacterial
  • a bronchodilator helping open nasal passages, bronchi and bronchioles in the lungs.
  • a vasodilator playing an important role in the dilation of blood vessels so that oxygen can be properly distributed throughout the body.

How NO prevents infection

NO is produced in the paranasal sinuses, a group of four air-filled spaces that surround the nasal cavity.  According to a 1999 paper by Lundberg and Weitzberg, NO in the nasal airways could represent an important first line of defence against infection.[1]  It is known to be broadly antifungal, antiviral and antibacterial.[2]

Research conducted during a previous Coronavirus epidemic — that is, the Severe Acute Respiratory Syndrome Coronavirus (SARSCoV) epidemic showed that NO inhibited the replication of SARSCoV in a dose-dependent manner, meaning that higher levels had a greater inhibitory effect on the replication of the virus.[3]

How NO helps with breathing

NO is also a vasodilator playing an important role in the dilation of blood vessels so that oxygen can be properly distributed throughout the body.[4]

Impaired breathing leads to poor air circulation and lower levels on beneficial NO in the nose and sinuses, thus creating an environment beneficial for bacterial growth and inflammation.  Studies carried out at the Karolinska Institute in Sweden show that humming increases airflow in the sinuses.  Further, the levels of NO increase 15 to 20-fold by humming compared with quiet exhalation.[2]  By breathing through the nose, we harness the various properties of NO including its germicidal powers.[1]

How humming promotes good health

According to The Humming Effect by Jonathan and Andi Goldman, humming also reduces stress, induces calmness, enhances sleep, lowers heart rate and blood pressure, produces neurochemicals such as oxytocin, increases lymphatic circulation and melatonin production, releases endorphins and creates new neural pathways in the brain.  All of these help reduce stress and promote health and well-being.[5]

Humming Exercise

Here is a simple humming exercise you can do if you feel you are coming down with a respiratory infection, sinusitis or are unwell.  You can do it any time as a preventative measure to help boost immunity. We associate humming with cheerfulness and you’ll notice that it’s difficult to hum and feel down at the same time.

  1. Breathe through your nose with mouth closed and the tip of your tongue resting behind your top front teeth. If you can’t breathe through your nose do the Nose Unblocking Exercise first.
    The nose — use it or lose it
  2. As you exhale slowly through your nose make a sustained ‘hmmmmmm …’ sound. Avoid pushing the air out with force.  As with everything to do with breathing, this should be done gently.
  3. Now, breathe in gently through your nose and repeat.
  4. The sinuses are air-filled cavities located around your nose, temples and above your eye sockets. To increase the effect of the exercise you can gently massage those areas while doing the exercise.
  5. If you have a stubborn blocked nose or sinusitis, repeat this exercise for 5 to 10 minutes, 2 to 4 times a day for a few days or until symptoms improve.

When doing this exercise the vibrations you might feel are helping increase air circulation and production of NO in your nasal and sinus cavities.

Further Reading

Is nasal breathing your first line of defense against Coronavirus?

Immune-protective effects of nasal breathing and NO for Coronaviruses — Self-care potential

To learn more about the benefits of humming read The Humming Effect by Jonathan and Andi Goldman.[5]

Important note

Please note neither this post nor any linked articles claim that nasal breathing or humming prevent or cure COVID-19. However, now more than ever, it makes sense both for physical and psychological reasons to take any steps that may improve our health. Like the advice to wash our hands frequently the advice to nasal breathe also gives us a sense that there is something we can do, a sense of control and anything that makes us feel less stressed is also good for our immune system.

About this post


Nicky McLeod, BA, MBIBH, Breathing Educator
Nicky McLeod — Breathing Clinic Nelson
Glenn White, BSC, MBIBH, BBEA, Breathing Educator, March 2020
Glenn White — Buteyko Breathing Clinics


We acknowledge and thank our colleagues including Rosalba Courtenay, Patrick McKeown, Jill McGowan, Tess Graham for their invaluable and ongoing contributions about the importance of boosting natural immunity to prevent and overcome respiratory infections, including COVID-19.


[1] Lundberg JON, Weitzberg E Thorax 1999

[2]  Maiscalco, M Journal Karolinska University Press 2006

[3]  Akerstrom, S et al Journal of Virology Feb 2005 p 1966-1969

[4]  Moncado, S. Higgs EA British Journal of Pharmacology (2006) 147,

[5]  Jonathan and Andi Goldman. The Humming Effect


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