Did you know that mouth breathing can significantly contribute to abnormal development of children’s faces, crooked teeth, snoring, obstructive sleep apnea, poor concentration, ADHD, respiratory problems including asthma, hay fever and poor sports performance? The purpose of Breathe Through Your Nose Week is to highlight the negative health consequences associated with this seemingly innocuous habit.

BENEFITS OF NOSE BREATHING

Nose breathing imposes approximately 50 percent more resistance to the air stream in normal individuals than does mouth breathing, resulting in 10-20 percent more O2 uptake.

Nasal breathing warms and humidifies incoming air. (Air entering the nose at 6 °C will be warmed to 30 °C by the time it touches the back of the throat, and a cosy 37 °C (body temperature) upon reaching its final destination – the lungs);

Nasal breathing removes a significant amount of germs and bacteria from the air you breathe in;

Nasal breathing results in more regular breathing;

Nitric oxide (NO) is released in the nasal airways in humans. During inspiration through the nose this NO will follow the airstream to the lower airways and the lungs.

Lundberg JO. Nitric oxide and the paranasal sinuses. Anat Rec (Hoboken).2008 Nov;(291(11)):1479-84
Lundberg – Read abstract – Nitric Oxide and paranasal sinuses.

Nitric oxide plays an important role in vasoregulation, homeostasis, neurotransmission, immune defence and respiration.

Rabelink, A J (1998), “Nobel prize in Medicine and Physiology 1998 for the discovery of the role of nitric oxide as a signalling molecule”, Nederlands tijdschrift voor geneeskunde (1998 Dec 26) 142 (52): 2828–30

Culotta E, Koshland DE Jr.. NO news is good news. Science.1992 Dec 18;(258(5090)):1862-5

Nitric oxide from the back of your nose and your sinuses into your lungs. This short-lived gas dilates the air passages in your lungs and does the same to the blood vessels.

Roizen, MF, and Oz, MC, 2008. You on a diet revised, The Owners Manual for waist management. New York. Collins.

Since NO is continuously released into the nasal airways the concentration will be dependent on the flow rate by which the sample is aspirated. Thus, nasal NO concentrations are higher at lower flow rates.

Lundberg J, Weitzberg E. Nasal nitric oxide in man. Thorax.1999;(54):947-952

NOW COMPARE THE EFFECTS FROM MOUTH BREATHING

Mouth breathing children are at greater risk of developing forward head posture, and reduced respiratory strength;

Breathing through the mouth results in a dry mouth, which increases acidification of the mouth and results in more dental cavities and gum disease;

Breathing through the mouth contributes to dehydration (mouth breathing during sleep results in waking up with a dry mouth);

Mouth breathing causes bad breath due to altered bacterial flora.

Breathing through the mouth has been proven to significantly increase the number of occurrences of snoring and obstructive sleep apnea

The effect of mouth breathing on asthma, sports performance, sleep disordered breathing, ADHD and craniofacial development is explored below.

MOUTH BREATHING AND ASTHMA

We speculate that asthmatics may have an increased tendency to switch to oral breathing, a factor that may contribute to the pathogenesis of their asthma.

Chest. 1999 Dec;116(6):1646-52. Route of breathing in patients with asthma. Kairaitis K, Garlick SR, Wheatley JR, Amis TC

www.chestjournal.chestpubs.org/content/116/6/1646.full
www.ncbi.nlm.nih.gov/pubmed/10593789

Enforced oral breathing causes a decrease in lung function in mild asthmatic subjects at rest, initiating asthma symptoms in some. Oral breathing may play a role in the pathogenesis of acute asthma exacerbations.

Respirology. 2008 Jun;13(4):553-8. Enforced mouth breathing decreases lung function in mild asthmatics. Hallani M, Wheatley JR, Amis TC.

www.ncbi.nlm.nih.gov/pubmed/18494947

In the first step of a study of the relation of nasal and oral breathing during moderate treadmill exercise to the onset of bronchoconstriction in young patients with perennial bronchial asthma, it was observed that most subjects spontaneously breathed with their mouths open when instructed to breathe “naturally.” Subsequently, when they were required to breathe only through the nose during the exercise, an almost complete inhibition of the postexercise bronchoconstrictive airway response was demonstrated. When instructed to breathe only through the mouth during exercise, an increased bronchoconstrictive airway response occurred, as measured by spirometry, flow-volume relationships, and body plethysmography. These findings suggest that the nasopharynx and the oropharynx play important roles in the phenomenon of exercise-induced bronchoconstriction.

Am Rev Respir Dis. 1978 Jul;118(1):65-73. The beneficial effect of nasal breathing on exercise-induced bronchoconstriction.

Shturman-Ellstein R, Zeballos RJ, Buckley JM, Souhrada JF.

www.ncbi.nlm.nih.gov/pubmed/677559?dopt=Abstract

The effect of nasal as well as oral breathing during level-ground running for 6 min on the post exercise bronchial response was studied in fifteen people (five asthmatics with exercise liability, five asthmatics with no such liability and five normals). Each patient did the exercise twice; once with the nose clipped and once with the mouth closed. FEV1 was measured before exercise, immediately after exercise and at 5, 10, 15, 20 and 30 min thereafter. A fall in FEV1 of 20% or more from the basal level was taken as evidence of bronchoconstriction. When the patients were required to breath only through the nose during the exercise, the post-exercise bronchoconstrictive response was markedly reduced as compared with the response obtained by oral breathing during exercise, indicating a beneficial effect of nasal breathing. Nasal breathing was beneficial as compared with oral breathing in normals as well. In the five asthmatics with no exercise liability no appreciable difference was observed. This study suggests that the oropharynx and nasopharynx play important roles in the causation of exercise-induced asthma.

Clin Allergy. 1981 Sep;11(5):433-9.

Effect of nasal and oral breathing on exercise-induced asthma.
Mangla PK, Menon MP.

www.ncbi.nlm.nih.gov/pubmed/7318162

Mouth breathing is a trait of hyperventilation.Bronchoconstriction was induced in asthmatic patients by means of isocapnic hyperventilation with dry air. Responses both within a day and between days did not differ significantly and corresponded closely with those observed after exercise. The mean fall in forced expiratory volume in one second (FEV1) observed with both techniques was equivalent to 36%. Isocapnic hyperventilation with dry air, as used in this study, was a potent stimulus and provoked a reproducible response. The method was physically less demanding than exercise and was more acceptable to patients.

Thorax. 1981 Aug;36(8):596-8.
Hyperventilation of exercise to induce asthma?

Tweeddale PM, Godden DJ, Grant IW.

www.ncbi.nlm.nih.gov/pubmed/7314034

Mouth breathing is a trait of hyperventilation.The appearance of an asthmatic crisis in the minutes following physical exercise is common in symptomatic asthma. Exercise induced asthma (EIA) is linked to hyperventilation; voluntary isocapnic hyperventilation is capable of triggering a crisis. It is well established at present that EIA and post-hyperventilation asthma (HIA) are triggered by a rise in heat and water loss by the airways, which is inherent in hyperventilation. The respective role of water loss and cooling the airways are uncertain but one tends to think at the present time that the primary stimulus is the variation in osmolality of the liquid lining the epithelium. However, a relationship between the quantity of energy dissipated in the airways and the severity of EIA or HIA exists, although it is less tight than was once thought. Hyperventilation lends itself better than exercise to establishing dose-effect curves linking bronchial response to minute ventilation.
Rev Mal Respir. 1987;4(5):217-23.[Bronchial provocation tests using hyperventilation].[Article in French] Lockhart A.

www.ncbi.nlm.nih.gov/pubmed/3324231

A link between the upper and lower airways has been convincingly demonstrated both in health and disease. To what extent the nose may be involved in children’s asthma, has so far not been thoroughly investigated. In this study, we compared symptoms and signs from the upper airways in children with asthma and in children without to find out more about this. Methods The study group included 27 asthmatic children, the control group 29 age and sex-matched healthy volunteers. The children were investigated by a senior ENT-specialist. Their parents completed questionnaires about symptoms and signs of upper airway disorders. Skin prick tests, total IgE, acoustic rhinometry, and an X-ray of the epipharynx were performed. The data from the groups were compared. Results Nasal blockage, mouth breathing, day time sleepiness, apnoeas, itching, sneezing, and hearing impairment were more prevalent in asthmatics compared with controls (p<0.05). For nasal blockage the mean VAS-scores were 52.4 and 30.6 for asthmatics and controls, respectively. For daytime sleepiness the corresponding figures were 34.6 and 23.1. The adenoid-nasopahrynx-index was larger, indicating reduced palatal airway in the former compared with the latter (p<0.05). Conclusions As the site of upper airway obstruction in asthmatic children appears to be the epipharynx, the adenoids may play a key-role.

Nasal symptoms and signs in children suffering from asthma. S.K. SteinsvågemaiL, B. Skadberg, K. Bredesen

www.ijporlonline.com/article/S0165-5876%2807%2900006-7/abstract

The use of mouth taping, to encourage nose breathing, is currently being recommended by some Buteyko instructors, but its effects on physiology are unknown. This preliminary study aimed to investigate the effects of mouth taping on end-tidal carbon dioxide (ETCO2). Design Preliminary study with an experimental single group repeated measures design. Setting Nine university students and staff with mild stable asthma. Interventions Physiological data were recorded before and during two experimental breathing conditions: oral breathing and nasal breathing (encouraged by mouth taping), carried out on two separate occasions 5–14 days apart. Between visits, participants familiarised themselves with the mouth taping technique. Outcome measures Primary outcome was ETCO2. Secondary outcomes were respiratory rate, pulse rate, oxygen saturation and lung function. Results There was an increase in ETCO2 from baseline during both breathing conditions. The mean ETCO2 for oral breathing was 4.4 kPa versus 4.7 kPa for nasal breathing, with mean difference of 0.3 kPa (95% confidence interval −0.2 to 0.8 kPa). It was also found that ETCO2 increased more in ‘natural’ oral breathers than ‘natural’ nasal breathers. Conclusions The results of this pilot study provide data to power a larger study and suggest ETCO2 may be increased in people with asthma during nasal breathing, particularly in those who normally primarily breathe through the mouth. The methodology was found to be acceptable to this sample of people with mild asthma.
The use of mouth taping in people with asthma: a pilot study examining the effects on end-tidal carbon dioxide levels
Ajay Bishop, Michelle Rawle, Anne Bruton. School of Health Professions and Rehabilitation Sciences, University of Southampton, Highfield, Southampton SO17 1BJ, UK

www.sciencedirect.com/science/article/pii/S0031940606001921

Enhanced perception of nasal loading may trigger increased oral breathing in asthmatics, potentially enhancing exposure to nonconditioned inhaled gas and contributing to the occurrence and/or severity of bronchoconstrictive exacerbations.
Eur Respir J. 2008 Apr;31(4):800-6. Epub 2007 Nov 21. Initiating oral breathing in response to nasal loading: asthmatics versus healthy subjects. Hallani M, Wheatley JR, Amis TC.

www.ncbi.nlm.nih.gov/pubmed/18032447

Airway dehydration triggers exercise-induced bronchoconstriction in virtually all patients with active asthma. Dehydration of the expired air is present in asthmatic patients in the emergency department. The bronchoconstriction triggered by dry-air tachypnea challenge in the laboratory can be prevented by humidifying the inspired air.
Airway Dehydration* A Therapeutic Target in Asthma? Edward Moloney, MB; Siobhan O’Sullivan, PhD; Thomas Hogan, MD; Leonard W. Poulter, DSc; and Conor M. Burke, MD, FCCP

www.ncbi.nlm.nih.gov/pubmed/12065342