The Importance of Nose Breathing for Immune Defense

The Importance of Nose Breathing for Immune Defense closeup of a womans nose (Dreamstime)

Patrick McKeown By Patrick McKeown Thursday, 23 September 2021 12:37 PM Current | Bio | Archive

As the surge in COVID-19 cases, hospitalizations and deaths continues, researchers are working hard to help the world get back to normal. There is still a long way to go, and many of us feel helpless in the face of such a global problem.

However, amidst the continuous flow of medical advice, there has been some important research around immunity that has not been widely disseminated. In the ongoing discussion about a respiratory virus, the issue of how we breathe has been overlooked.

Nose Breathing Filters and Sterilizes Inhaled Air

The nose performs around 30 functions on behalf of the body. Significantly, it filters inhaled air before the air reaches the lungs. As you breathe in, potentially harmful bacteria, pollutants and micro-organisms are trapped in the nasal mucus.

The nose also sterilizes the air via a gas called nitric oxide (NO). Large amounts of NO are produced in the paranasal sinuses and inhaled during nose breathing. NO inhibits the growth of various pathogens, including viruses. Effectively, it forms a first line of immune defense for the body.

Nitric Oxide Prevents Viral Replication

Following the first SARS coronavirus, researchers established that NO inhibits viral replication. Numerous papers explore its relevancy in COVID-19, too. A 2021 article by Kobayashi states that: “NO inhibits SARS-CoV-2 host cell entry, viral replication, and host immune response.”

Why is the Nose So Important?

When you breathe through an open mouth, you bypass the naval cavity, nasal nitric oxide, and the protective functions of the nose. Mouth breathing irritates and dehydrates the airways, so infection is more easily introduced.

Moreover, mouth breathers may inhale a much larger volume of air (10 to 15 liters per minute compared with 4 to 6 liters in nose breathing). This increases the risk of introducing a heavy viral load directly into your lungs.

Within other body systems, mouth breathing triggers the autonomic stress response, leaving you less resilient and more vulnerable to infection.

A 2020 article by Martel and colleagues points to lifestyle factors that reduce NO in the airways, in particular, mouth breathing. The paper argues that nasal breathing could help decrease viral load.

The same article mentions empirical evidence that mouth taping during sleep can prevent infection with the common cold. Mouth breathing, whether it is constant or intermittent, interrupts the inhalation of nasal nitric oxide, promoting unobstructed viral replication.

The paper concludes that, “mouth breathing during sleep may therefore worsen the symptoms of COVID-19.”

In my work with clients and breathing instructors, I have been advocating for mouth taping during sleep for many years. It reduces snoring and sleep apnea and helps achieve the deep, restorative sleep the body needs for healing, immune function and good health.

While nasal breathing will itself increase the amount of NO in the airways, scientists have also found that humming can produce 15 times more NO than normal exhalation. It is thought that oscillations in the air speed up the exchange of gases between the nasal cavity and sinuses.

Harnessing Nasal Nitric Oxide

In a push to provide accessible, affordable solutions to help people stay well during the pandemic, scientists have been trialing a nitric oxide nasal spray. Phase II clinical trials of SaNOtize, which the company’s chief science officer, Dr. Chris Miller describes as, “like a hand sanitizer for the nose,” began in June 2020.

The team had initially been developing the spray to treat chronic sinusitis but redirected their research as the benefits of NO for coronavirus patients became clear.

This is no lucky strike. Professor Ferid Murad of Stanford University is one of the board members at SaNotize.

Murad shared the Nobel Prize in Medicine in 1998 for his work in defining the importance of nitric oxide and its healing properties within the human body. Results of a UK trial of the SaNOtize spray in patients with mild COVID-19 were published in August 2021 in the Elsevier Public Health Emergency Collection.

Researchers observed a 95% reduction in viral load within 24 hours, and a 99% reduction within 72 hours. The company is currently seeking emergency approval to introduce SaNOtize to the market.

Key Takeaway

The biggest missing piece of the puzzle in all the public health advice around coronavirus, is the importance of nose breathing. COVID-19 presents a serious challenge, and it would be irresponsible and inaccurate to suggest that nose breathing would provide full protection.

However, nasal breathing, during rest, exercise, and sleep, will help support your immune system, and increase the concentration of anti-viral nitric oxide naturally produced in the nose. As you go about your day, whether you’re wearing a protective mask or not, it is vital to remember to breathe through your nose.

Patrick McKeown is an internationally renowned breathing coach, author and speaker. He is creator of Oxygen Advantage®, founder of Buteyko Clinic International and a fellow of the Royal Society of Biology in the UK. Published works include research in the Journal of Clinical Medicine, and books including The Breathing Cure.