Obligate nasal breathing

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Obligate nasal breathing describes a physiological necessity to breathe through the nose (or other forms of external nares, depending on the species) as opposed to breathing through the mouth.


The term may be misleading, as it implies that the organism has no choice but to breathe through its nose; however, it is also used to describe cases where effective breathing through the mouth is possible but not preferred.[1] Alternatively, the term has been defined by some as the ability to breathe through the nose while swallowing. While this ability is a common trait of obligate nasal breathers, clearly this definition does not require that nasal breathing in any way be obligatory to the animal. Even in obligate nasal breathers such as horses, rabbits, and rodents, there is a potentially patent path for air to travel from the mouth to the lungs which can be used for endotracheal intubation. It has been suggested that obligate nasal breathing is an adaptation especially useful in prey species, as it allows an animal to feed while preserving their ability to detect predators by scent.[2]


Horses are considered obligate nasal breathers. The respiratory system of the horse prevents horses from breathing orally. The epiglottis rests above the soft palate while the animal is not swallowing, forming an airtight seal. Oral breathing can only occur with significant anatomical abnormalities or pathological conditions. For example, denervation of the pharyngeal branch of the vagus nerve results in dorsal displacement of the soft palate (DDSP),[3] and it has been suggested that this leads to a clinical syndrome which may include oral breathing.[4] However, significant respiratory dysfunction including airway obstruction is observed with DDSP, and the animal cannot function normally in this state.

Rabbits, cats, and rodents are also obligate nasal breathers. Like horses, the normal anatomical position of the epiglottis causes it to be engaged over the caudal rim of the soft palate, sealing the oral pharynx from the lower airways.[5] Air entering the mouth will not fully make it to the lungs.[6] Even so, rabbits with advanced upper airway disease will attempt to breathe through their mouths.

Many other mammals, such as dogs and adult humans, have the ability to breathe indefinitely through either the oral or nasal cavity.[7][8]


According to Jason Turowski, MD of the Cleveland Clinic, "we are designed to breathe through our noses from birth — it’s the way humans have evolved."[9] This is because 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.[10][11] In addition, nasal breathing produces nitric oxide within the body while mouth breathing does not.[12][10][13][14] Mouth breathing also leads to dry mouth, throat infections, a reduced sense of taste,[11] and other chronic conditions.[13][15][16][17] Nasal breathing is a research interest in Orthodontics (and the related field of Myofunctional Therapy)[18] and for biological anthropologists.[19]


Human infants are commonly described as obligate nasal breathers as they breathe through their nose rather than the mouth.[20] Most infants, however, are able to breathe through their mouth if their nose is blocked.[20] There are however certain infants with conditions such as choanal atresia in which deaths have resulted from nasal obstruction.[20] In these cases there are cyclical periods of cyanosis. The infant initially attempts to breathe through the nose, and is unable to; hypercapnia occurs, and many babies instinctively begin to cry. While crying, oral ventilation occurs and cyanosis subsides. There is variation in the length of time until a baby begins oral breathing, and some will never cease attempts at nasal breathing. It has also been suggested that infants may not be able to sustain oral breathing for significant lengths of time, because of the weakness of the muscles required to seal the nasal airway and open the oral airway.[20] One study employing monitored anatomical occlusion concluded that human infants are not obligate nasal breathers:[21] its sample of nineteen infants, ranging in age from 1 day to 7.5 months, reliably transitioned from nose to mouth breathing after nasal occlusion, providing evidence that infants possess the physiological capability to mouth breathe.


Some authors argue that nasal breathing offers a greater advantage over mouth breathing during exercise.[14]

Additional people and activities

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 the life of the Plains Indians, and painted portraits that depicted them.[22] He was also the author of several books, including The Breath of Life[23] (later retitled as Shut Your Mouth and Save Your Life) in 1862.[24][25] 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.[26] 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.[26] He also observed that mothers repeatedly closed the mouth of their infants while they were sleeping, to instill nasal breathing as a habit.[27]


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.[28][29][30] They tell their students that the "nose is for breathing, the mouth is for eating."[29][31][32][28]

See also


  1. ^ Rodenstein, D. O.; Kahn, A.; Blum, D.; Stănescu, D. C. (1 May 1987). "Nasal occlusion during sleep in normal and near-miss for sudden death syndrome infants". Bulletin européen de physiopathologie respiratoire. 23 (3): 223–226. ISSN 0395-3890. PMID 3664013.
  2. ^ Negus, VE (1927). "The Function of the Epiglottis". Journal of Anatomy. 62 (Pt 1): 1–8. PMC 1250045. PMID 17104162.
  3. ^ Holcombe, SJ; Derksen, FJ; Stick, JA; Robinson, NE (1998). "Effect of bilateral blockade of the pharyngeal branch of the vagus nerve on soft palate function in horses". American Journal of Veterinary Research. 59 (4): 504–8. PMID 9563638.
  4. ^ Susan J. Holcombe (1998). "Neuromuscular Regulation of the Larynx and Nasopharynx in the Horse" (PDF). Proceedings of the Annual Convention of the AAEP. 44: 26.
  5. ^ Stephen J. Hernandez-Divers (2007). "The Rabbit Respiratory System: Anatomy, Physiology, and Pathology" (PDF). Proceedings of the Association of Exotic Mammal Veterinarians: 61–68.
  6. ^ Carter, Lou (23 March 2020). "How Do Rabbits Breathe?". Rabbit Care Tips. Retrieved 31 August 2020.
  7. ^ Radostits, Otto M.; Mayhew, I. G. Joe; Houston, Doreen M., eds. (2000). Veterinary clinical examination and diagnosis. Philadelphia: W. B. Saunders. ISBN 0-7020-2476-7.[page needed]
  8. ^ Trabalon, Marie; Schaal, Benoist (3 July 2012). "It Takes a Mouth to Eat and a Nose to Breathe: Abnormal Oral Respiration Affects Neonates' Oral Competence and Systemic Adaptation". International Journal of Pediatrics. 2012: e207605. doi:10.1155/2012/207605. ISSN 1687-9740. PMC 3397177. PMID 22811731.
  9. ^ Turowski, Jason (29 April 2016). "Should You Breathe Through Your Mouth or Your Nose?". Cleveland Clinic. Retrieved 28 June 2020.
  10. ^ a b Glazier, M.D., Eve (4 November 2019). "'Nose breathing has more benefits than mouth breathing". The Times and Democrat. Retrieved 9 July 2020.
  11. ^ a b "Your Nose, the Guardian of Your Lungs". Boston Medical Center. Retrieved 29 June 2020.
  12. ^ Cohan, Alexi (26 July 2020). "Nitric oxide, a 'miracle molecule,' could treat or even prevent coronavirus, top doctors say". Boston Herald. Retrieved 27 July 2020.
  13. ^ a b Dahl, Melissa (11 January 2011). "'Mouth-breathing' gross, harmful to your health". NBC News. Retrieved 28 June 2020.
  14. ^ a b Berman, Joe (29 January 2019). "Could nasal breathing improve athletic performance?". Washington Post. Retrieved 31 May 2020.
  15. ^ Martel, Jan; Ko, Yun-Fei; Young, John D.; Ojcius, David (6 May 2020). "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.
  16. ^ Nall, Rachel (22 September 2017). "What's wrong with breathing through the mouth?". Medical News Today. Retrieved 31 May 2020.
  17. ^ Valcheva, Zornitsa (January 2018). "THE ROLE OF MOUTH BREATHING ON DENTITION DEVELOPMENT AND FORMATION" (PDF). Journal of IMAB. Retrieved 31 May 2020.
  18. ^ 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. doi:10.52010/ijom.2014.40.1.4. PMID 27295847.
  19. ^ Gross, Terry (27 May 2020). "How The 'Lost Art' Of Breathing Can Impact Sleep And Resilience". National Public Radio (NPR)/Fresh Air. Retrieved 23 June 2020.
  20. ^ a b c d Bergeson, P. S.; Shaw, J. C. (2001). "Are Infants Really Obligatory Nasal Breathers?". Clinical Pediatrics. 40 (10): 567–9. doi:10.1177/000992280104001006. PMID 11681824. S2CID 44715721.
  21. ^ Rodenstein, D O; Perlmutter, N; Stanescu, D C (March 1985). "Infants are not obligatory nasal breathers". American Review of Respiratory Disease. 131 (3): 343–347. doi:10.1164/arrd.1985.131.3.343 (inactive 31 July 2022). PMID 3977172. Retrieved 31 August 2020.{{cite journal}}: CS1 maint: DOI inactive as of July 2022 (link)
  22. ^ "Catlin Virtual Exhibition". Smithsonian American Art Museum. Archived from the original on 25 September 2014. Retrieved 28 October 2014.
  23. ^ The breath of life, or mal-respiration, and its effects upon the enjoyments & life of man. HathiTrust. 1862. Retrieved 28 June 2020.
  24. ^ "George Catlin on Mouth Breathing". PubMed. Retrieved 2 July 2020.
  25. ^ Nestor, James (2020). Breath: The New Science of a Lost Art. Riverhead Books. p. 48. ISBN 978-0735213616.
  26. ^ a b Nestor, James (2020). Breath: The New Science of a Lost Art. Riverhead Books. p. 49. ISBN 978-0735213616.
  27. ^ Nestor, James (2020). Breath: The New Science of a Lost Art. Riverhead Books. p. 50. ISBN 978-0735213616.
  28. ^ a b "Q&A: Is Mouth Breathing OK in Yoga?". Yoga Journal. 12 April 2017. Retrieved 26 June 2020.
  29. ^ a b Payne, Larry. "Yogic Breathing: Tips for Breathing through Your Nose (Most of the Time)". Yoga For Dummies, 3rd Edition. Retrieved 26 June 2020.
  30. ^ Himalayan Institute Core Faculty, Himalayan Institute Core Faculty (13 July 2017). "Yogic Breathing: A Study Guide". Himalayan Institute of Yoga Science and Philosophy. Retrieved 26 June 2020.
  31. ^ Krucoff, Carol (2013). Yoga Sparks. New Harbinger Publications. ISBN 9781608827022. Retrieved 31 May 2020.
  32. ^ Jurek, Scott (2012). Eat and Run. Houghton Mifflin. ISBN 978-0547569659. Retrieved 31 May 2020.

Further reading

External links