From very early writings it is very clear that nose breathing was considered the “thing to do” and mouth breathing indicated a lack of class, stupidity or some form of deviant behavior.

An artist named George Catlin (1796-1872), after living with and observing native Americans for over 40 years,  said “If I were to endeavor to bequeath to posterity the most important Motto which human language can convey, it should be in three words—Shut your mouth.”. He then wrote “Shut Your Mouth and Save Your Life“, describing his experience, observations and conclusions.

The evidence continues to mount that the ONLY way we should breathe – ever  – is through our noses, inhaling and exhaling, during sleep, exercise, illness – you name it.

“Why?”, you might ask, “what benefit is there to nose breathing only?”

Your nose is very specifically designed to breathe through, keep you and your lungs healthy, detect odors – both good and bad.

How does it do that?

To achieve everything mentioned above, your nose (nasal cavity) is made up of the following:

  1. Nostrils
  2. Nasal mucosa
  3. Turbinates
  4. Sinuses
  5. Olfactory nerve structure
  6. Adenoids

Click to view larger image


1. Nostrils

Your nostrils are much smaller than your mouth – they are small because your body doesn’t need high volumes of air for just about anything you do!

They are small because your body needs to process that air before it goes into your lungs! (There’s more to this, but that is later.)

Hairs in the nostrils trap the large particles in the air entering the nasal cavity.


2. Nasal Mucosa

Almost as soon as the air gets into the nasal cavity, it hits the nasal mucosa which lines the entire cavity, including the turbinates and sinuses.

The nasal mucosa is a mucus secreting membrane, covered with fine cilia. Incoming dirt particles are trapped by the mucus and then are moved by the cilia into the nasal cavity through small sinus openings.

Cilia – small hairs which move mucus
Sol – the fluid bottom layer housing the cilia
Gel – a viscous layer overlying the cilia

A wide range of antimicrobial agents have been detected in nasal mucosa, although concentrations vary widely between individuals. In fact, “the ability of nasal secretions to kill or inhibit the growth of a range of microbes has been demonstrated in a number of studies” (Microbial Inhabitants of Humans by Michael Wilson)

Click to view larger image


3. Turbinates

The turbinates or conchae, are long, narrow curled shelves of bone which extend into the breathing passage of the nasal cavity. They divide the nasal airway into four passages.

The 3 turbinates are:

  • superior – the smallest. Protect the olfactory system. Also, the openings to the posterior ethmoidal sinuses are under them.
  • middle – as long as a little finger. over the openings of the maxillary sinuses
  • inferior – the largest. This turbinate can be so large it can block the airway.

They serve several functions:

  • force inhaled air to flow in a steady, regular pattern around the largest possible surface area of nasal mucosa
  • filter inhaled air
  • humidify inhaled air up to 98%
  • heat inhaled air to 89-93°F
  • create turbulence in the inhaled air
  • first line of defense against harmful microbes
  • protect your olfactory epithelium containing the smell receptors
  • reabsorb moisture from exhaled air

The turbinates make up for most of the mucosal tissue of the nasal cavity. The are necessary for fully functional respiration. The also have airflow pressure and temperature sensing nerve endings which respond to weather conditions and the changing needs of the body.

They are also what alternates the dominant sides of your nose (where it is easier to breathe out of one nostril than the other – this changes every few hours all day and night).

Click to view larger image


4. Sinuses

Your nasal cavity contains opening to 4 paired sinuses (see diagram to the right):

  1. Frontal (above the eyes)
  2. Ethmoidal (each side of nose)
  3. Sphenoidal (behind the ethmoidal)
  4. Maxillary (cheeks)

While the full function of the sinuses is still being debated, but the proposed functions are that they:

  • help drain mucus from the nasal cavity
  • support the structure of the skull and facial bones
  • assist in heating and humidifying air
  • help protect the face from injury
  • give resonance to the voice
  • insulate sensitive structures like the eyes and dental roots from rapid temperature fluctuations
  • help regulate gas pressures in the nasal cavity
  • assist in immune defense

We also know that

  • the composition of air in the maxillary sinuses is similar to venous blood – higher in CO2 and lower in O2 than inhaled air.
  • air diffusion in the sinuses is slow and limited, which helps prevent the mucus surfaces from drying out
  • maintain a near sterile environment with limited access for pathogens to contaminate them
  • the concentration of nitric oxide is high in the sinuses

Click to view larger image


5. Olfactory Nerve Structure

The olfactory nerve is the first cranial nerve and contains the nerve fibers related to smell.

It is somewhat unique among cranial nerves because it is capable of some regeneration if damaged.

It is also the shortest of your twelve cranial nerves.

Click to view larger image


6. Adenoids

The adenoids lie above the tonsils and are at the base of the nasal cavity.

Like tonsils, adenoids help to defend the body from infection. They trap bacteria and viruses which you breathe in through your nose. They contain cells and antibodies of the immune system to help prevent throat and lung infections.

Because adenoids trap germs that enter the body, adenoid tissue sometimes temporarily swells (gets puffier) as it tries to fight off an infection. The swelling sometimes gets better, but sometimes adenoids can get infected themselves.

Especially in young children, the adenoids can swell to the point of completely blocking the airway, meaning mouth breathing is mandatory. In this case it can cause an atypical development in the appearance of the face. Features of this include mouth breathing, an elongated face, prominent incisors, an incomplete development of the upper jaw, short upper lip, elevated nostrils, and a high arched palate.

Symptoms of a severely enlarged adenoids are:

  • a very stuffy nose, so a kid can breathe only through his or her mouth
  • snoring and trouble getting a good night’s sleep
  • swollen glands in the neck
  • ear problems

George Catlin in his book Breath Of Life published in 1861, illustrates the effect of mouth breathing on the face (adenoid facies) in many engravings, and advocates nose-breathing.

Click to view larger image


Summary

So if you are nose breathing are:

  1. Filtering the air – the pollens, the dirt, the microbes – very little of it actually gets into your lungs
  2. Warming the air to nearly body temperature
  3. Moistening the air so it doesn’t dry the airways out
  4. Optimizing efficient exchange of gases because of the warm, moist air in the alveoli
  5. Circulating the air so there is good mix of inhaled and residual air in the alveoli
  6. Giving yourself the best chance to fight incoming harmful bacteria