Should nasal breathing be included in COVID-19 protection guidelines?
A while back I was having a conversation with my sister and her boyfriend (let's call him Scott) about strange impulsive behaviours one might sometimes express.
My sister and I agreed that both of us had an impulse of closing our mouth when passing something that is potentially smelly or unsafe, for example, a large pile of garbage or when we are stuck in a crowded bus with little ventilation in the middle of summer. Scott found this utterly strange. He said:
“Why would you keep your mouth closed while still breathing in the same air through your nose?”.
We agreed that we do not really know, but had a feeling that we were told to do so in our childhood. Upon which Scott concluded: “You and your weird Eastern European upbringing”.
Knowing what I know now, I can conclude that our grandmother was on to something and I will try to convince you to raise awareness about your breathing technique as well.
Proper breathing is especially important now, during the time of the COVID-19 pandemic. It can potentially save you from getting infected.
It all comes down to a little wonder molecule called nitric oxide. Breathing through the nose creates it, while mouthbreathing does not.
Nitric oxide has been studied as a potential recovery agent way back in 2002 when Severe acute respiratory syndrome (SARS) outbreak began. This outbreak was caused by the same family of viruses — the coronaviruses, as the current COVID-19 outbreak.
During that time, a small study of severely sick SARS patients took place in one Beijing hospital. All patients were on respirators, but one group received inhaled nitric oxide therapy and the other did not (they were the control). Patients who received nitric oxide showed, among other things, improved arterial oxygenation. Their oxygen saturation increased from 93% to a mean level of 99% (P < 0.05). The oxygen saturation levels in the control group remain the same.
This is a small study so the results must be taken with a grain of salt (my favourite nutritional supplement). In this study, the patients were already infected and had to take in external nitric oxide, but even then, it helped them get better sooner.
It is interesting to think that for prevention purposes we don't need to take in external nitric oxide because each of us has the ability to produce their own batches of it!
There are a few important roles of nitric oxide in the respiratory system:
- Protection against pathogens
- Increased mucus production
- Increased ciliary movement
- Vasodilatation, bronhodilatation
Protection against pathogens
Nitric oxide is produced in the paranasal sinuses but the precise origin and physiology are still unknown.
It has antimicrobial effects against a range of microbes but most important (for the current pandemic) is its potential of eradicating SARS coronavirus which is similar to SARS-CoV-2 (causes COVID-19).
The proposed mechanisms of nitric oxide action are the inhibition of certain viral spike proteins, which prevents binding of the coronavirus to its cellular receptor.
In other words, nitric oxide can potentially destroy “the key” the coronavirus needs to open the doors of the attacked organism, thus preventing further damage.
Increased mucus production
You may think of mucus as being just an annoyance during the cold season, but it is there for a good reason. The mucosal barrier is the first line of defence against all things trying to come into our organism from outside — In this case, the foreign substance is the air coming through the nose. This air is potentially filled with harmful microorganisms and the body needs to react in order to protect itself — and it does that in a very slimy style.
One of the key factors for the mucosa to do its job properly is the right humidity. As this research suggests, low air humidity of the surroundings could inactivate the mucins, making people more susceptible to viruses and other harmful substances from the environment.
Mucins of the nasal cavity form the nasal mucosal barrier. They belong to glycans— a set of highly glycosylated proteins specific for each person.
The dehydration of mucins happens in heated spaces, where the air is very dry. This may explain why there is a rise in respiratory infections through the wintertime when indoor time is increased.
Here you might see the “weird” part of my Eastern European upbringing. It was believed that cold air causes infections and that you should never sit down where there is a draft of air — the famous “propuh”.
It is important to note that even if the air from the surroundings is slightly dryer, the nose itself helps to humidify it (through complex mechanisms).
Having all this in mind, what my grandmother meant when saying “close your mouth while passing something yucky” is actually:
“Breath through your nose so that nitric oxide can be produced, air can be properly humidified, and mucins can properly protect you. “
You can now see that a person who is a habitual mouth breather bypasses all of this goodness that comes with nasal breathing.
Who is a habitual mouth breather?
Many of us are not even aware of our breathing technique and don’t think much about it. Some of us even keep their mouth closed during the workday (because having your mouth open is not really socially acceptable behaviour) but that does not leave you in the clear.
If you have chronic rhinitis, open mouth at rest, or if you often wake up with dry mouth and bad morning breath, you may be a mouthbreather as well.
Mouth breathing through the night is especially dangerous and can affect a persons’ quality of life and even physical appearance! (study here and here).
Proper breathing in COVID-19 prevention guidelines
One of the guidelines for COVID-19 protection is hand washing. Washing your hands with soap can eliminate virus particles from your hands, lowering the risk of infection. This elimination works because the virus is not inside of your organism yet, but on it. If you think about it, the nasal cavity is still not the proper inside of our bodies so eliminating the virus there is a crucial next step in protection.
Having all of this in mind, to protect yourself from COVID-19 consider:
- Following the recommended guidelines
- Breathing nasally most of the time (and just raising awareness of your breathing technique)
- Increasing humidity of your living space (help your mucosa do its job)
Fun fact: I mentioned that one of the roles of nitric oxide is vasodilation. This process connects vascular with the respiratory system. If we take into consideration that nitric oxide is being produced in our blood vessels as well, with the help of the endothelial glycocalyx, this connection could be the key to finding COVID-19 treatment.
