Mouth breathing

Mouth breathing refers to the act of breathing through the mouth (as a temporary backup system) if there is an obstruction to breathing through the nose, which is the designated breathing organ for the human body.[1][2] Chronic mouth breathing is usually associated with illness.[citation needed] The term "mouth-breather" developed a pejorative meaning within English slang.

Mouth breathing
SymptomsSnoring, dry mouth, hoarse voice, bad breath, fatigue
CausesChronic nasal congestion
TreatmentTreatment of the underlying cause of nasal congestion if present, building a habit to breathe through the nose


Image 23 from the 1903 book by William F. Barry, M.D., The Hygiene of the Schoolroom. Barry describes this child as having "the typical face of a mouth-breather."

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."[3] Currently, the Macmillan Dictionary defines the term "mouth breather" as "a stupid person."[4][5]


Jason Turowski, MD of the Cleveland Clinic states that "we are designed to breathe through our noses from birth — it's the way humans have evolved."[1][2] Thus, the impact of chronic mouth breathing on health is a research area within orthodontics (and the related field of myofunctional therapy)[6] and anthropology.[7] It is classified into three types: obstructive, habitual, and anatomic.[8]:281

Nasal breathing produces nitric oxide within the body, while mouth breathing does not.[2][9][10][11] In addition, the Boston Medical Center notes that it is the job of the nose to filter out all of the particles that enter the body, as well as to humidify the air we breathe, add moisture to it, and warm it to body temperature.[12] 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 blood stream."[12] Thus, chronic mouth breathing usually leads to illness.[10][13][14][15][16] In about 85% of cases, it is an adaptation to nasal congestion,[8]:281[14] and frequently occurs during sleep.[13] More specialized causes include: antrochoanal polyps;[17]:350 a short upper lip which prevents the lips from meeting at rest (lip incompetence);[8]:281 and pregnancy rhinitis which tends to occur in the third trimester of pregnancy.[18]:435

Potential effectsEdit

Conditions associated with mouth breathing include cheilitis glandularis,[17]:490 Down syndrome,[19]:365 anterior open bite,[18]:225 tongue thrusting habit,[18]:225 cerebral palsy,[20]:422 ADHD,[21][22] sleep apnea,[23] and snoring.[23] In addition, gingivitis,[18]:85 gingival enlargement,[18]:85 and increased levels of dental plaque[18]: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.[18]:85

Chronic mouth breathing in children may affect dental and facial growth.[16] It may also lead to the development of a long, narrow face, sometimes termed long face syndrome, when the mouth breathing is related to adenoid hypertrophy.[citation needed] Malocclusion of the teeth (e.g., crowded teeth) is also suggested to result from chronic mouth breathing in children. Conversely, it has been suggested that a long thin face type, with corresponding thin nasopharyngeal airway, predisposes to nasal obstruction and mouthbreathing,[14] i.e., a long thin face may cause mouth breathing rather than the other way around. Facial form is also strongly influenced by genetic factors.

COVID-19 studiesEdit

As of April 2020, studies and trials are underway that examine the possible benefits of nitric oxide in the treatment of COVID-19.[9][24][25][26] This research is based on the fact that nitric oxide was investigated as an experimental therapy for SARS.[27] Brian Strickland, MD, a fellow in Wilderness Medicine at Massachusetts General Hospital who studies "acute respiratory distress" in high altitudes, is applying this research towards COVID-19.[28][29] He is currently involved in clinical trials which apply the use of inhaled nitric oxide as a treatment for COVID-19.[30] This approach was inspired by the work of Associate Professor of Emergency Medicine at the Harvard Medical School N. Stuart Harris, who has been studying the effects of altitude sickness on mountain climbers, such as those who climb Mount Everest. Harris noticed that the consequences of high level altitude sickness on the human body mirrored COVID-19's dysfunctional impact on the lungs. His focus on nitric oxide comes from its role in being able to breathe in high altitudes.[28][31] According to WCVB-TV, similar trials are being conducted at Tufts Medical Center.[32] Other studies speculate that replacing mouth breathing (which decimates NO) with nasal breathing (which increases NO)[2][10][11] is a "lifestyle change" that "may also help to reduce SARS-CoV-2 viral load and symptoms of COVID-19 pneumonia by promoting more efficient antiviral defense mechanisms in the respiratory tract."[13]


Studies suggest that nasal breathing offers a greater advantage over mouth breathing during exercise.[11]

Additional people and activitiesEdit

George CatlinEdit

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.[33] He was also the author of several books, including The Breath of Life[34] (later retitled as Shut Your Mouth and Save Your Life) in 1862.[35][36] 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.[37] 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.[37] He also observed that mothers repeatedly closed the mouth of their infants while they were sleeping, in order to instill nasal breathing as a habit.[38]


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,[39][40][41] using the phrase, "the nose is for breathing, the mouth is for eating."[39][40][42][43]

See alsoEdit


  1. ^ a b Turowski, Jason (2016-04-29). "Should You Breathe Through Your Mouth or Your Nose?". Cleveland Clinic. Retrieved 2020-06-28.
  2. ^ a b c d Glazier, M.D., Eve (2019-11-04). "'Nose breathing has more benefits than mouth breathing". The Times and Democrat. Retrieved 2020-07-09.
  3. ^ Kelly, John (2016-08-23). "How '80s Is the Slang in Stranger Things?". Slate. Retrieved 2020-07-02.
  4. ^ "Macmillan Dictionary: Mouthbreather". The Macmillan Dictionary. Retrieved 2020-05-31.
  5. ^ Wollan, Malia (2019-04-23). "How to Be a Nose Breather". New York Times. Retrieved 2020-05-31.
  6. ^ Frey, Lorraine (November 2014). "The Essential Role of the Com in the Management of Sleep-Disordered Breathing: A Literature Review and Discussion". The International Journal of Orofacial Myology. Int J Orofacial Myology. 40: 42–55. PMID 27295847.
  7. ^ Gross, Terry (2020-05-27). "How The 'Lost Art' Of Breathing Can Impact Sleep And Resilience". National Public Radio (NPR)/Fresh Air. Retrieved 2020-06-23.
  8. ^ a b c Phulari BS, ed. (2011). Orthodontics : principles and practice. New Delhi: Jaypee Bros. Medical Publishers. ISBN 9789350252420.
  9. ^ a b Cohan, Alexi (2020-07-26). "Nitric oxide, a 'miracle molecule,' could treat or even prevent coronavirus, top doctors say". Boston Herald. Retrieved 2020-07-27.
  10. ^ a b c Dahl, Melissa (2011-01-11). "'Mouth-breathing' gross, harmful to your health". NBC News. Retrieved 2020-06-28.
  11. ^ a b c Berman, Joe (2019-01-29). "Could nasal breathing improve athletic performance?". Washington Post. Retrieved 2020-05-31.
  12. ^ a b "Your Nose, the Guardian of Your Lungs". Boston Medical Center. Retrieved 2020-06-29.
  13. ^ a b c Martel, Jan; Ko, Yun-Fei; Young, John D.; Ojcius, David (2020-05-06). "Could nasal nitric oxide help to mitigate the severity of COVID-19?". Microbes and Infection. 22 (4–5): 168–171. doi:10.1016/j.micinf.2020.05.002. PMC 7200356. PMID 32387333.
  14. ^ a b c Rao A, ed. (2012). Principles and Practice of Pedodontics (3rd ed.). New Delhi: Jaypee Brothers Medical Pub. pp. 169, 170. ISBN 9789350258910.
  15. ^ Nall, Rachel (September 22, 2017). "What's wrong with breathing through the mouth?". Medical News Today. Retrieved 2020-05-31.
  16. ^ a b Valcheva, Zornitsa (January 2018). "THE ROLE OF MOUTH BREATHING ON DENTITION DEVELOPMENT AND FORMATION" (PDF). Journal of IMAB. Retrieved 2020-05-31.
  17. ^ a b Barnes L, ed. (2009). Surgical pathology of the head and neck (3rd ed.). New York: Informa healthcare. ISBN 978-1-4200-9163-2.
  18. ^ a b c d e f g Newman MG, Takei HH, Klokkevold PR, Carranza FA, eds. (2012). Carranza's clinical periodontology (11th ed.). St. Louis, Mo.: Elsevier/Saunders. ISBN 978-1-4377-0416-7.
  19. ^ Regezi JA, Sciubba JJ, Jordan RK (2011). Oral pathology : clinical pathologic correlations (6th ed.). St. Louis, Mo.: Elsevier/Saunders. ISBN 978-1-4557-0262-6.
  20. ^ Cawson RA, Odell EW (2008). Cawson's essentials of oral pathology and oral medicine (8th ed.). Edinburgh: Churchill Livingstone. ISBN 978-0-7020-4001-6.
  21. ^ Won, Dana (February 2017). "It Is Just Attention-Deficit Hyperactivity Disorder…or Is It?". Journal of Developmental and Behavioral Pediatrics : JDBP. J Dev Behav Pediatr. 38 (2): 169–172. doi:10.1097/DBP.0000000000000386. PMC 5401711. PMID 28079611.
  22. ^ Sano, Masahiro (October 2013). "Increased oxygen load in the prefrontal cortex from mouth breathing: a vector-based near-infrared spectroscopy study". NeuroReport. 24 (17): 935–940. doi:10.1097/WNR.0000000000000008. PMC 4047298. PMID 24169579.
  23. ^ a b Pacheco, Maria Christina Thome (July–August 2015). "Guidelines proposal for clinical recognition of mouth breathing children". Dental Press Journal of Orthodontics. 20 (4): 39–44. doi:10.1590/2176-9451.20.4.039-044.oar. PMC 4593528. PMID 26352843.
  24. ^ Katsnelson, Alla (2020-05-20). "Multiple clinical trials test whether NO gas can treat and prevent COVID-19". Chemical & Engineering News. Retrieved 2020-07-14.
  25. ^ Gander, Kashmira (2020-04-07). "What Is Nitric Oxide? How the Gas That Gave Us Viagra Could Help Treat Coronavirus Patients". Newsweek. Retrieved 2020-06-25.
  26. ^ "Nitric Oxide Investigated as COVID-19 Treatment". WebMD. Retrieved 10 April 2020.
  27. ^ Åkerström, Sara; Mousavi-Jazi, Mehrdad; Klingström, Jonas; Leijon, Mikael; Lundkvist, Åke; Mirazimi, Ali (1 February 2005). "Nitric Oxide Inhibits the Replication Cycle of Severe Acute Respiratory Syndrome Coronavirus". Journal of Virology. 79 (3): 1966–1969. doi:10.1128/JVI.79.3.1966-1969.2005. PMC 544093. PMID 15650225.
  28. ^ a b Powell, Alvin (2020-05-06). "Applying wisdom from the Himalayas to the ER's COVID battle". The Harvard Gazette. Retrieved 2020-06-25.
  29. ^ "Lessons from the Backcountry in Finding a Potential COVID-19 Treatment". Massachusetts General Hospital. 2020-06-24. Retrieved 2020-06-25.
  30. ^ "Inhaled Nitric Oxide Therapy for Emergency Room COVID-19 Patients". Massachusetts General Hospital. 2020-06-24. Retrieved 2020-06-25.
  31. ^ Meredith, Sam (2020-05-01). "How the gas that gave the world Viagra could help treat coronavirus patients". CNBC. Retrieved 2020-07-05.
  32. ^ Riemer, Emily (2020-06-23). "Tufts researchers test inhaled nitric oxide as COVID-19 treatment". WCVB-TV. Retrieved 2020-07-05.
  33. ^ "Catlin Virtual Exhibition". Smithsonian American Art Museum. Archived from the original on 25 September 2014. Retrieved 28 October 2014.
  34. ^ "The breath of life, or mal-respiration,and its effects upon the enjoyments & life of man". HathiTrust. Retrieved 2020-06-28.
  35. ^ Nestor, James (2020). Breath: The New Science of a Lost Art. Riverhead Books. p. 48. ISBN 978-0735213616.
  36. ^ "George Catlin on Mouth Breathing". PubMed. Retrieved 2020-07-02.
  37. ^ a b Nestor, James (2020). Breath: The New Science of a Lost Art. Riverhead Books. p. 49. ISBN 978-0735213616.
  38. ^ Nestor, James (2020). Breath: The New Science of a Lost Art. Riverhead Books. p. 50. ISBN 978-0735213616.
  39. ^ a b Yoga Journal Editors (2017-04-12). "Q&A: Is Mouth Breathing OK in Yoga?". Yoga Journal. Retrieved 2020-06-26.
  40. ^ a b Payne, Larry. "Yogic Breathing: Tips for Breathing through Your Nose (Most of the Time)". Yoga For Dummies, 3rd Edition. Retrieved 2020-06-26.
  41. ^ Himalayan Institute Core Faculty, Himalayan Institute Core Faculty (2017-07-13). "Yogic Breathing: A Study Guide". Himalayan Institute of Yoga Science and Philosophy. Retrieved 2020-06-26.
  42. ^ Krucoff, Carol (2013). Yoga Sparks. New Harbinger Publications. ISBN 9781608827022. Retrieved 2020-05-31.
  43. ^ Jurek, Scott (2012). Eat and Run. Houghton Mifflin. ISBN 978-0547569659. Retrieved 2020-05-31.

Further readingEdit

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

External linksEdit