enriched air from our dead space back into the alveoli of the lungs. When the mouth is used for respiration, the dead space becomes smaller, shorter and wider. Nasal passages are no longer a part of the breathing route. Air exchange is stronger as if air gets directly to lungs alveoli from outside. This reduces alveolar O2 and arterial blood CO2 concentrations. This does not take place with nose breathing. Furthermore, nasal breathing route provides more resistance for respiratory muscles as compared to oral breathing (the route for mouth breathing is shorter and it has a greater cross sectional area). During nose breathing, in order to maintain the same CO2 content in alveoli and blood, we can breathe more so that to lower CO2 content in the body. Then this will result in more mechanical work for our respiratory muscles. As an alternative, we can breathe little less while producing less mechanical work. What is the practical result? Due to an in-built tendency to minimize losses of energy, the human organism is likely, as for nose breathing, to breathe less and. hence, tolerate higher arterial and alveolar CO2, than to exert more strain on working breathing muscles.

In their study "An assessment of nasal functions in control of breathing" (Tanaka et al, 1988), Japanese researchers discovered that end-tidal CO2 concentrations were higher during nose breathing than during oral breathing. This research study revealed that a group of healthy volunteers had an average CO2 of about 43.7 mm Hg for nose breathing and only around 40.6 mm Hg for oral breathing. In practice, in terms of body oxygenation or the CP, this corresponds to 45 s and 37 s at sea level. Hence, mouth breathing reduces oxygenation of the whole body.

Each mouth breather needs to know this short summary of immediate negative biochemical effects of mouth breathing related to CO2:
– Reduced CO2 content in alveoli of the lungs (hypocapnia)
– Hypocapnic vasoconstriction (constrictions of blood vessels due to CO2 deficiency)
– Suppressed Bohr effect
– Reduced oxygenation of cells and tissues of all vital organs of the human body
– Anxiety, stress, addictions, sleeping problems and negative emotions
– Slouching and muscular tension
– Biochemical stress due to cold, dry air entering into the lungs
– Biochemical stress due to dirty air (viruses, bacteria, toxic and harmful chemicals) entering into the lungs
– Possible infections due to absence of the autoimmunization effect 
– Pathological effects due to suppressed nitric oxide utilization, including vasoconstriction, decreased destruction of parasitic organisms, viruses, and malignant cells (by inactivating their respiratory chain enzymes) in alveoli of the lungs, inflammation in blood vessels, disruption of normal neurotransmission, hormonal effects.

Practically, when a household member is sick (flu or cold), the still healthy people could breathe either through their nose, teaching the own immune system how to deal with the pathogenic bacteria or viruses, or through their mouth, as for mouth breathing, allowing these pathogens to gain access, settle and reproduce themselves in various parts of the body causing the infection.

Which medical therapy provides techniques and methods to get rid of mouth breathing?

It is the key goal of the Buteyko breathing method to stop mouth breathing and ensure nose breathing 24/7 to prevent all these mouth breathing effects.

For many mouth breathers and sick people quick health improvement (the initial stage of breathing normalization) is accomplished by one change only: learning how to breathe through the nose 24/7. Just this step alone can make a big difference in health of many people so that the main symptoms are reduced and less medication is required.

Dr. Buteyko, while studying respiration during physical activity, observed that breathing through the nose made a big difference in the after-effects of physical exercise. Moreover, physical activity with oral breathing often led to lower CPs and CO2 later, whereas nose breathing during walking and other physical activities was beneficial.

Most medical doctors do not know when and how sick people should exercise. It is known that exercise can be useful, but sick people often die or experience heart attacks, exercise-induced asthma attacks, and other exacerbations or acute states of their diseases during or after physical exercise. However, when physical exercise is done with avoidance of any mouth breathing, physical activity is 100% safe even for severely sick people. (They would not be able to have intensive exercise and will rely on lighter activities, like walking. We are going to learn more about rules and types of beneficial exercise later.)

Since many patients and sick people open their mouth and breathe through the mouth during sleep at night, in the 1960s Dr. Buteyko’s patients invented a technique (mouth taping) is described in "Learn here" Section of this website.

Permanent solution for mouth breathing problems

Use your will power to stop mouth breathing. If a mouth breather suffers from stuffy, or blocked, or running nose and sinusitis, they can exist or appear only in conditions of abnormal breathing. In order for these problems to exist, you should breathe at least 2 times more air at rest than the medical norm. As a result, you have 2 times less body oxygen than the medical norm. Check you body oxygen level (special breath holding time test) and see the truth. The norm is 40 seconds. Hence, there is a simple relationship between the blocked nose and this simple DIY health test:
– If your body oxygen level is less than 20 s, your nose can easily get blocked due to hyperventilation;
– If your body oxygen is more than 20 s, you can avoid mouth breathing.

Conclusion. If you have problems with mouth breathing, your goal is to slow down your automatic or unconscious breathing pattern so that to have over 20 of body oxygen 24/7. "Learn" Section provides numerous breathing techniques and methods to improve body oxygen levels.