Why is it better to breathe through your nose than your mouth? – 08/18/2023 – Balance and Health

Breathing is an essential process that apparently doesn’t need to be learned: we all breathe from birth and we don’t need to train ourselves to do so.

Is it really like that? In truth no. According to the most recent studies, it seems that there is some technique to be learned. Among other things, because breathing through the nose and through the mouth is not the same thing.

An average person breathes about 10,000 to 12,000 liters of air a day. This air, however clean it may be, contains suspended particles such as dust, bacteria, viruses or fungal spores that are deposited in the airways and on the alveolar surfaces of the lung.

But there’s no reason to panic: the respiratory system knows how to clean and defend itself. In reality, only extremely small particles can reach the lung, with a diameter between 3 and 5 microns.

The Battle of the Eyelashes

How does the respiratory system manage to stop the rest? With the help of superheroes named Eyelashes.

Eyelashes are tiny hair-like projections, much smaller than the tip of a pin.

They are found by the thousands in the mucosa of the respiratory tract: each cell in the mucosa of the nose and bronchi has about 25 to 30 cilia, with an average length of 5 to 7 microns.

The cilia protrude from the cells and move like the bristles of a brush when we sweep.

Its function is to clean the nose of particles of up to 0.5 millimeters in diameter that enter, dragging them towards the pharynx so that they are eliminated from the nose in just 10 or 15 minutes.

The superpower of these cell heroes is their high speed: they shake more than a thousand times a minute, managing to push up the mucus that lines the trachea, trapping microorganisms and pathogenic particles in this layer of mucus.

Once there, they can be coughed up or dragged into the mouth, where there are no cilia, and swallowed. This makes them a crucial defense mechanism against infections of the nose, sinuses and bronchial tubes.

immunological differences

The nose is covered by a tissue with very peculiar physical characteristics. At the immunological level it is also special because the “screening” of the pathogens that enter with the air we breathe is carried out in the nose.

The lining of the nose is always deciding whether to attack a pathogen or allow it to enter, because the damage caused by an immune battle would be worse for our body.

This process implies a certain tolerance to pathogens that normally do not cause us great harm.

Part of this “gatekeeper” role is played by a type of B cell that produces antibodies called IgA, a little different from the IgG that circulates in the blood and that we hear more about during the pandemic.

Why the nose and not the mouth? The mouth is fundamentally the entry point for food, both solid and liquid. Its mucosa has another type of specialization and lacks cilia that filter the air.

Its job is to deal with pathogens that try to get in with the food we eat. So, just as we don’t eat through our nose, we shouldn’t breathe through our mouth either.

In addition, the air that enters through the nose becomes warmer and repels germs.

Breathing through the mouth alters the bones of the face

Habitual mouth breathing may be due to genetic factors, poor oral habits or nasal obstruction (hypertrophy of adenoids or tonsils), presence of nasal polyps, nasal septum deviation, turbinate hypertrophy or sinusitis.

In addition, mouth breathing can be related to respiratory allergies, weather conditions or poor sleeping position.

And its effects should not be underestimated. Mouth breathing can alter the arrangement of facial bones in children.

According to a scientific review, breathing through the mouth causes changes in the development of facial bones and malocclusion in children (the mouth does not close properly due to poor alignment of the teeth).

Among other changes, the mandible and maxilla rotate backwards and downwards, and there is a tendency for labial inclination of the upper anterior teeth.

The problem is that closing the mouth badly causes problems with chewing muscles, neck and even headaches in adults.

More than half of 12-year-olds suffer from mild to severe malocclusion, according to the 2020 oral health survey carried out by the Magazine of the Illustrious General Council of Faculties of Dentists and Stomatologists in Spain.

As in adults, we also modify our posture if we habitually breathe through the mouth: we bend the neck forward and change the position of the head and neck to adapt the angle of the pharynx and facilitate the entry of air into the mouth. Look in the mirror and you can see it.

If you’re still not convinced about the benefits of breathing through your nose, try to relax. You will notice that you breathe naturally through your nose, while you will have to force yourself to breathe through your mouth.

Use your mouth for breathing only in “case of emergency”.

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This article was written by researchers Matilde Cañelles López from the Philosophy Institute (IFS-CSIC), María Mercedes Jiménez Sarmiento and Nuria Eugenia Campillo from the Margarita Salas Biological Research Center (CIB-CSIC) in Spain. This note originally appeared on The Conversation and is published here under a Creative Commons license.