Mouth breathing
Mouth breathing, medically known as chronic oral ventilation, is long-term breathing through the mouth. It often is caused by an obstruction to breathing through the nose, the innate breathing organ in the human body. Chronic mouth breathing may be associated with illness. The term "mouth-breather" has developed a pejorative slang meaning.

Etymology
In the early 20th century, "mouth-breather" was a technical term used by doctors to describe children who were breathing through their mouths due to an underlying medical condition. English lexicographer Jonathon Green notes that by 1915, the phrase "mouth-breather" had developed a pejorative connotation within English slang, defined as a "stupid person." Currently, the Macmillan Dictionary defines the term "mouth breather" as a pejorative noun that is used to mean "a stupid person."

Overview
Jason Turowski, MD of the Cleveland Clinic states that "we are designed to breathe through our noses from birth — its the way humans have evolved." Thus, the impact of chronic mouth breathing on health is a research area within orthodontics (and the related field of myofunctional therapy) and anthropology. It is classified into three types: obstructive, habitual, and anatomic.: 281 Nasal breathing produces nitric oxide within the body, while mouth breathing does not. In addition, the Boston Medical Center notes that the nose filters out particles that enter the body, humidifies the air we breathe and warms it to body temperature. In contrast, however, mouth breathing "pulls all pollution and germs directly into the lungs; dry cold air in the lungs makes the secretions thick, slows the cleaning cilia, and slows down the passage of oxygen into the bloodstream." As a result, chronic mouth breathing may lead to illness. In about 85% of cases, it is an adaptation to nasal congestion,: 281  and frequently occurs during sleep. More specialized causes include: antrochoanal polyps;: 350  a short upper lip which prevents the lips from meeting at rest (lip incompetence);: 281  and pregnancy rhinitis which tends to occur in the third trimester of pregnancy.: 435

Potential effects
Conditions associated with mouth breathing include cheilitis glandularis,: 490  Down syndrome,: 365  anterior open bite,: 225  tongue thrusting habit,: 225  cerebral palsy,: 422  ADHD, sleep apnea, and snoring. In addition, gingivitis,: 85  gingival enlargement,: 85  and increased levels of dental plaque: 108  are common in persons who chronically breathe through their mouths. The usual effect on the gums is sharply confined to the anterior maxillary region, especially the incisors (the upper teeth at the front). The appearance is erythematous (red), edematous (swollen) and shiny. This region receives the greatest exposure to airflow during mouth breathing, and it is thought that the inflammation and irritation is related to surface dehydration, but in animal experimentation, repeated air drying of the gums did not create such an appearance.: 85 Breathing through your mouth decreases saliva flow. Saliva has minerals to help neutralize bacteria, clean off the teeth, and rehydrate the tissues. Without it, your risk of gum disease and cavities increases.Chronic mouth breathing in children may affect dental and facial growth. It may also lead to the development of a long, narrow face, sometimes termed long face syndrome. Conversely, it has been suggested that a long thin face type, with corresponding thin nasopharyngeal airway, predisposes to nasal obstruction and mouth breathing.

Additional approaches to mouth breathing
George Catlin
George Catlin was a 19th-century American painter, author, and traveler, who specialized in portraits of Native Americans in the Old West. Travelling to the American West five times during the 1830s, he wrote about, and painted portraits that depicted, the life of the Plains Indians. He was also the author of several books, including The Breath of Life (later retitled as Shut Your Mouth and Save Your Life) in 1862. It was based on his experiences traveling through the West, where he observed a consistent lifestyle habit among the Native American communities he encountered: a preference for nose breathing over mouth breathing. He also observed that they had perfectly straight teeth. He repeatedly heard that this was because they believed that mouth breathing made an individual weak and caused disease, while nasal breathing made the body strong and prevented disease. He also observed that mothers repeatedly closed the mouth of their infants while they were sleeping, to instill nasal breathing as a habit.

Yoga
Yogis such as B. K. S. Iyengar advocate both inhaling and exhaling through the nose in the practice of yoga, rather than inhaling through the nose and exhaling through the mouth, using the phrase, "the nose is for breathing, the mouth is for eating."

References
Further reading
Nestor, James (2020). Breath: The New Science of a Lost Art. Riverhead Books. ISBN 978-0735213616.

External links

Effects of Mouth Breathing - WebMD (video clip)