Some Biochemistry of Nose Breathing

In “The Health Benefits of Nose Breathing,” Ruth Allen (Behavioral Medicine Practitioner) writes:

It has been estimated that approximately one third of people don’t breathe well enough to sustain normal health. These people do not get enough oxygenation of their cells, tissues and organs. In the book Behavioural and Psychological Approaches to Breathing Disorders, Dr Chandra Patel describes the problem with breathing as follows:

“We start life with a breath, and the process continues automatically for the rest of our lives. Because breathing continues on its own, without our awareness, it does not necessarily mean that it is always functioning for optimum mental and physical health. The opposite is true often. The problem with breathing is that it seems so easy and natural that we rarely give it a second thought.”
…
The human nose was designed for breathing (and smelling) whereas the mouth was designed for eating, drinking and speaking. However, it has been estimated that up to 30-50% of modern adults breathe through the mouth, especially during the early morning hours.

From: https://www.lenus.ie/bitstream/handle/10147/559021/JAN15Art7.pdf

The article has some interesting information in it, such as

Mouth breathing is a typical characteristic of over breathing. When an individual over breathes, too much carbon dioxide is lost from the blood and this results in reduced oxygenation of tissues and organs. In contrast, when breathing volume is reduced towards normal, through nose breathing, higher carbon dioxide in the blood decreases the affinity between oxygen and haemoglobin, resulting in greater oxygenation of tissues and organs.

From: https://www.lenus.ie/bitstream/handle/10147/559021/JAN15Art7.pdf

and

Enzymes responsible for nitric oxide production have been demonstrated both in the nose and in the paranasal sinuses. Nitric oxide is a potent bronchodilator and vasodilator. Therefore it helps lower blood pressure and significantly increases the lungs’ oxygen-absorbing capacity. It is also known to be antifungal, antiviral and antibacterial.

From: https://www.lenus.ie/bitstream/handle/10147/559021/JAN15Art7.pdf