- Updated on November 10, 2021
Quantitative evaluation of the orofacial morphology: anthropometric measurements in healthy and mouth-breathing children.
Cattoni DM, Fernandes FD, Di Francesco RC, De Latorre Mdo R.
International Journal Orofacial Myology. 2009 Nov;35:44-54.
Craniocervical posture and hyoid bone position in children with mild and moderate asthma and mouth breathing.
Chaves TC, de Andrade E Silva TS, Monteiro SA, Watanabe PC, Oliveira AS, Grossi DB.
International Journal Pediatr Otorhinolaryngol. 2010 Jun 19.
Polysomnographic findings are associated with cephalometric measurements in mouth-breathing children.
Juliano ML, Machado MA, de Carvalho LB, Zancanella E, Santos GM, do Prado LB, do Prado GF.
Journal Clin Sleep Med. 2009 Dec 15;5(6):554-61.
The impact of speech therapy on asthma and allergic rhinitis control in mouth breathing children and adolescents.
Campanha SM, Fontes MJ, Camargos PA, Freire LM.
Journal Pediatr (Rio J). 2010 May-Jun;86(3):202-8.
[Prevalence of mouth breathing in children from an elementary school]
Felcar JM, Bueno IR, Massan AC, Torezan RP, Cardoso JR.
Cien Saude Colet., 2010 Mar;15(2):437-44.
Changes in vertical dentofacial morphology after adeno-tonsillectomy during deciduous and mixed dentitions mouth breathing children–1 year follow-up study.
Souki BQ, Pimenta GB, Franco LP, Becker HM, Pinto JA.
Intern Journal Pediatrics Otorhinolaryngol. 2010 Jun;74(6):626-32.
Mouth breathing: adverse effects on facial growth, health, academics, and behavior.
General Dentstry 2010 Jan-Feb;58(1):18-25; quiz 26-7, 79-80.
Mouth breathing children have cephalometric patterns similar to those of adult patients with obstructive sleep apnea syndrome.
Juliano ML, Machado MA, de Carvalho LB, do Prado LB, do Prado GF.
Arq Neuropsiquiatr. 2009 Sep;67(3B):860-5.
Orientation and position of head posture, scapula and thoracic spine in mouth-breathing children.
Neiva PD, Kirkwood RN, Godinho R.
Intern Journal Pediatr Otorhinolaryngol. 2009 Feb;73(2):227-36.
Mouth breathing increases the pentylenetetrazole-induced seizure threshold in mice: a role for ATP-sensitive potassium channels.
Niaki SE, Shafaroodi H, Ghasemi M, Shakiba B, Fakhimi A, Dehpour AR.
Epilepsy Behav. 2008 Aug;13(2):284-9.
Enforced mouth breathing decreases lung function in mild asthmatics.
Hallani M, Wheatley JR, Amis TC.
Respirology. 2008 Jun;13(4):553-8.
The relationship between excursion of the diaphragm and curvatures of the spinal column in mouth breathing children.
Yi LC, Jardim JR, Inoue DP, Pignatari SS.
Journal Pediatr (Rio J). 2008 Mar-Apr;84(2):171-7.
[Characteristics of the stomatognathic system of mouth breathing children: anthroposcopic approach]
Cattoni DM, Fernandes FD, Di Francesco RC, Latorre Mdo R.
Pro Fono. 2007 Oct-Dec;19(4):347-51. Portuguese.
Aust J Sci Med Sport. 1995 Sep;27(3):51-5.
Comparison of maximal oxygen consumption with oral and nasal breathing.
Morton AR, King K, Papalia S, Goodman C, Turley KR, Wilmore JH.
University of Western Australia, Perth, Australia.
The major cause of exercise-induced asthma (EIA) is thought to be the drying and cooling of the airways during the ‘conditioning’ of the inspired air. Nasal breathing increases the respiratory system’s ability to warm and humidity the inspired air compared to oral breathing and reduces the drying and cooling effects of the increased ventilation during exercise. This will reduce the severity of EIA provoked by a given intensity and duration of exercise. The purpose of the study was to determine the exercise intensity (%VO2 max) at which healthy subjects, free from respiratory disease, could perform while breathing through the nose-only and to compare this with mouth-only and mouth plus nose breathing. Twenty subjects (11 males and 9 females) ranging from 18-55 years acted as subjects in this study. They were all non-smokers and non-asthmatic. At the time of the study, all subjects were involved in regular physical activity and were classified, by a physician, as free from nasal polyps or other nasal obstruction. The percentage decrease in maximal ventilation with nose-only breathing compare to mouth and mouth plus nose breathing was three times the percentage decrease in maximal oxygen consumption. The pattern of nose-only breathing at maximal work showed a small reduction in tidal volume and large reduction in breathing frequency. Nasal breathing resulted in a reduction in FEO2 and an increase in FECO2. While breathing through the nose-only, all subjects could attain a work intensity great enough to produce an aerobic training effect (based on heart rate and percentage of VO2 max).
Rhinology. 2007 Jun;45(2):102-11.
Observations on the ability of the nose to warm and humidify inspired air.
Naclerio RM, Pinto J, Assanasen P, Baroody FM.
Department of Surgery, Section of Otolaryngology-Head and Neck Surgery, The University of Chicago, Chicago, IL 60637, USA.
The major function of the nose is to warm and humidify air before it reaches to the lungs for gas exchange. Conditioning of inspired air is achieved through evaporation of water from the epithelial surface. The continuous need to condition air leads to a hyperosmolar environment on the surface of the epithelium. As ventilation increases, the hyperosmolar surface moves more distally, covering a larger surface area of the airway, and stimulates epithelial cells to release mediators that lead to inflammation. This inflammation is not identical to allergic inflammation, but causes both short-term and long-term changes in the epithelium. In the short-term, it increases paracellular water transport in an attempt to enhance conditioning, and it stimulates sensory nerves to initiate neural reflexes. It also disrupts channels in the cellular membrane, which might permit greater penetration of foreign proteins, such as allergens, leading to further inflammatory cascades. The long-term inflammation induced over time by the hyperosmolar milieu could worsen the ability of the nose to condition air, requiring more of the conditioning to occur in the lower airway and leading to adverse consequences for the respiratory system.
Mouth breathing and morning fatigue
L�th S, Petruson B,
Improved nasal breathing reduces snoring and morning tiredness. A 6-month follow-up study,
Archives of Otolaryngology and Head and Neck Surgery. 1996 Dec; 122(12): p.1337-1340.
Department of Otorhinolaryngology, Central Hospital, Sk�vde, Sweden
BACKGROUND: Dilation of the nasal valve region can increase the ability to breathe through the nose and reduce the negative intrathoracic pressure required for inspiration. Vibrations of the palate and soft tissues of the throat, which generate snoring sounds, can be prevented when patients inhale less heavily. OBJECTIVES: To evaluate the effect a nostril dilator has on patient snoring and tiredness in the morning and to determine how many patients would continue to use the device for half a year. DESIGN: For 6 months, 42 men who were heavy snorers graded their average tiredness in the morning and the patient’s sleeping partner graded the average snoring using a visual analog scale from 0 to 100. SETTING: All patients were examined at the Department of Otorhinolaryngology, Central Hospital, in Sk�vde, Sweden. RESULTS: When the nostril dilator was used there was a significant decrease in snoring after both 1- and 6-month reports. There was a significant correlation between diminution of snoring and less tiredness in patients in the morning. The compliance was good since 60% of patients continued to use the device during the 6-month resistance during sleep has on snoring and morning tiredness in patients.
Mouth breathing in asthmatics
Hallani M, Wheatley JR, Amis TC,
Enforced mouth breathing decreases lung function in mild asthmatics,
Respirology 2008 Jun; 13(4): p.553-558.
Ludwig Engel Centre for Respiratory Research, Westmead Millennium Institute, Sydney, New South Wales, Australia
BACKGROUND AND OBJECTIVE: Nasal breathing provides a protective influence against exercise-induced asthma. We hypothesized that enforced oral breathing in resting mild asthmatic subjects may lead to a reduction in lung function. METHODS: Asymptomatic resting mild asthmatic volunteers (n = 8) were instructed to breathe either nasally only (N; tape over lips) or orally only (O; nose clip) for 1 h each, on separate days. Lung function (% predicted FEV(1)) was measured using standard spirometry at baseline and every 10 min for 1 h. ‘Difficulty in breathing’ was rated using a Borg scale at the conclusion of the N and O periods. RESULTS: Baseline FEV(1) on the N (101.2 +/- 3.8% predicted) and O (102.7 +/- 3.9% predicted) days was not significantly different (P > 0.3). At 60 min, FEV(1) on the O day (96.5 +/- 4.1% predicted) was significantly less than on the N day (101.0 +/- 3.5% predicted; P < 0.009). On the N day, FEV(1) did not change with time (P > 0.3), whereas on the O day, FEV(1) fell progressively (slope = -0.06 +/- 0.01% FEV(1)/min, P < 0.0001; linear mixed effects modelling). Three subjects experienced coughing/wheezing at the end of the O day but none experienced symptoms at the end of the N day. Subjects perceived more ‘difficulty breathing in’ at the end of the O day (1.5 +/- 0.4 arbitrary units) than on the N day (0.4 +/- 0.3 arbitrary unit; P < 0.05). CONCLUSIONS: Enforced oral breathing causes a decrease in lung function in mild asthmatic subjects at rest, initiating asthma symptoms.
Petruson B, Theman K,
Reduced nocturnal asthma by improved nasal breathing,
Acta Otolaryngol. 1996 May; 116(3): p.490-492.
Department of ENT, Sahlgrenska University Hospital, G�teborg, Sweden.
The nose and not the mouth should be used for breathing as the nose has better air conditioning capacity. When air is inhaled through the mouth it may dry and cool the respiratory mucosa, which can lead to bronchoconstriction in sensitive patients with asthma. By dilating the nostrils you can increase nasal breathing in most subjects. The aim of this study was to investigate whether sleeping with dilated nostrils reduces nocturnal asthma. At the Asthma and Allergy Research Centre, Gothenburg, 15 out-patients with nocturnal asthma were selected. Every other night for 10 nights the test subjects slept with the nasal dilator Nozovent which has been shown to increase the nasal air-flow and decrease the need for mouthbreathing. Every morning the patients self-reported on a form whether they had woken with asthma during the night or if they had had to take asthma medication. When sleeping with the nasal dilator the patients woke up with asthma on 17 of 75 nights as compared with 32 of 75 when sleeping without the device (p < 0.01). Reduced nocturnal asthma was observed by 12 patients and less need for asthma medication at night by 7. None of the patients noted any side-effects due to the device. In conclusion, the easy-to-use and cheap medical device, Nozovent, which mechanically dilates the nostrils and improves nasal breathing, can reduce nocturnal asthma.
Nasal breathing, sleep apnoea, and snoring
Increased nasal breathing decreases snoring and improves oxygen saturation during sleep apnea,
Rhinology. 1994 Jun; 32(2): p.87-89.
ENT Department, Sahlgren’s Hospital, University of G�teborg, Sweden.
For many years ENT-specialists have performed surgery to create a good air passage in patients with different kinds of nasal deformities. When having a blocked nose one realizes the importance of being able to breathe through the nose. By moving the nasal wings aside with the fingers, or the medical device Nozovent, most people experience that it is easier to breathe through the nose than ever before, which can also be shown with rhinomanometry. When it is easier to inhale there is less energy in the air passing the palate which means less risk for vibrations creating snoring sounds. In different studies it has been possible to show that snoring can be decreased or prevented when the nasal dilator Nozovent is used. It has also been shown to result in a decrease of the sleep apnea index and improvement of arterial oxygen saturation during sleep apnoea.
Bushell MK, Baldock PJ, Antic R, Thornton AT, McEvoy RD,
Obligatory nasal breathing: effects on snoring and sleep apnea,
Med J Aust. 1991 Jul 15; 155(2): p.83-85.
Department of Thoracic Medicine, Royal Adelaide Hospital, North Terrace, SA, USA.
OBJECTIVE: To test the effects on snoring and sleep disordered breathing of a dental prosthesis (Snore-No-More) which is designed to decrease snoring by preventing mouth breathing during sleep. DESIGN: A crossover controlled trial. Each subject was studied on two nights a week apart. There was a control (no treatment) night and an experimental (treatment) night. The order of control and experimental nights was randomized. SETTING: The Royal Adelaide Hospital Sleep Laboratory. PARTICIPANTS: Fourteen male volunteers (age range, 36-59 years) were studied. All had a history of chronic snoring but denied other symptoms of obstructive sleep apnea syndrome. INTERVENTIONS: On experimental nights subjects wore the dental prosthesis for the whole study period. On control nights no device was worn. MAIN OUTCOME MEASURES: Studies were conducted overnight during the subject’s normal sleep period. The following measurements were made: (i) frequency and loudness of snores; (ii) frequency of disordered breathing events (apnoeas and hypopnoeas); (iii) mean and minimum arterial oxygen saturation while asleep; and (iv) sleep stages. RESULTS: The dental prosthesis did not change the mean frequency or mean intensity of snores. The number of sleep disordered breathing events per hour of sleep decreased by approximately one-third on experimental nights (mean +/- SEM events/h: control, 24.7 +/- 5.3; experimental, 16.1 +/- 3.3, P less than 0.05). Neither sleep architecture nor arterial oxygen saturation differed between control and experimental nights. CONCLUSION: Snores using the dental prosthesis Snore-No-More to produce obligatory nasal breathing are unlikely to experience clinical benefit.
Gleeson K, Zwillich CW, Braier K, White DP,
Breathing route during sleep,
Am Rev Respir Dis 1986 Jul; 134(1): p.115-120.
Nasal obstruction has been associated with apneic episodes during sleep. However, the normal distribution of nasal and oral air flow while asleep has not been investigated. To determine the normal route of ventilation during sleep, we studied 7 healthy men and 7 healthy women using a sealed face mask that mechanically separated nasal and oral air flow. Standard sleep staging techniques were employed. The subjects slept 297 +/- 29 (SEM) min, with a mean of 197 +/- 15 min of ventilation recorded. Ventilation was decreased during sleep as has been previously demonstrated. However, during sleep, we found that men breathed a greater percentage of total ventilation through the mouth (29.0 +/- 8.2%) than did women (5.0 +/- 1.0%, p less than 0.02). The same trend applied during wakefulness but did not reach significance (p = 0.06). Although none was symptomatic, 4 subjects, all men, had more than 3 apneas per hour. These 4 men had a greater percentage of mouth ventilation (37.3 +/- 19.0%) than did the other 10 subjects with few or no apneas (8.1 +/- 2.7%, p less than 0.02). It was also noted that increasing age in men was associated with an increasing percentage of mouth ventilation (r = 0.83 p less than 0.03) but this relationship was not observed in women. We conclude that mouth breathing may be associated with apneas during sleep and that breathing through the mouth occurs commonly in men, particularly in those who are older. This suggests that nasal breathing may be important in the maintenance of ventilatory rhythmicity during sleep.
[Physiopathology of mouth breathing. Snoring and apnea][Article in French]
Acta Otorhinolaryngol Belg. 1993; 47(2): p.157-166.
Centre Hospitalier de La Citadelle, Li�ge, Belgique.
Oral breathing causes changes in pulmonary mechanics as well as in the pressure of arterial blood gases. In response to increased nasal obstruction oro-nasal breathing occurs. The level of oro-nasal partitioning maintains an adequate level of respiratory resistance. Sleep disordered breathing, although not only related to oral breathing, is a common disorder. When upper airway resistance is increased limitation of flow occurs. Snoring indicates a mild degree of reduced airflow. Sleep apnea occurs when upstream pressure falls below a critical pressure (Pcrit). The mechanisms are reviewed.
Nasal congestion and hyperventilation
Nasal congestion and hyperventilation syndrome,
Am J Rhinol. 2005 Nov-Dec; 19(6): p.607-611.
Waitemata District Health Board, Auckland, New Zealand.
BACKGROUND: This article evaluates the prevalence of hyperventilation syndrome (HVS) in patients who continue to complain of ongoing nasal congestion, despite an apparently adequate surgical result and appropriate medical management. METHODS: Prospective case series of 14 patients from June 2002 to October 2003 was performed. Patients, who presented complaining of nasal congestion after previous nasal surgery and who appeared to have an adequate nasal airway with no evidence of nasal valve collapse, were evaluated for HVS. When appropriate, nasal steroids and oral antihistamines also had been tested without success. Three patients had end-tidal P(CO2) levels measured and five patients underwent breathing reeducation. RESULTS: All patients had an elevated respiratory rate (>18 breaths/minute) with an upper thoracic breathing pattern. Twelve of the 14 patients complaining of nasal obstruction had an elevated Nijmegen score indicative of HVS. An average number of 2.5 procedures had been performed on each patient. End-tidal P(CO2) levels were < or = 35 mmHg in the three patients who had expired P(CO2) levels measured. Breathing retraining was successful in correcting the nasal congestion in two of five patients. CONCLUSION: HVS should be included in the differential diagnosis of patients presenting with nasal congestion, particularly after failed nasal surgery. One possible explanation is increased nasal resistance secondary to low arterial P(CO2) levels. Another possible explanation is reduced alae nasae muscle activity secondary to the reduced activity of serotonin-containing raphe neurons. Additional surgery may not necessarily be the answer in HVS patients complaining of nasal congestion.
Nasal breathing as a treatment for hyperventilation: relevance of hemispheric activation,
Br J Clin Pract. 1989 Apr;43(4): p.161-162.
[The importance of normal nasal breathing for the physical and mental development of man and for diseases of the respiratory tract],
Munch Med Wochenschr. 1957 Sep 27; 99(39): p.1405-1408 (in German).