What Causes Asthma?
It is well documented in research that a child or adult with asthma habitually breathes more air than a person without asthma. This can be recognised by the bad habits of mouth breathing, upper chest breathing, audible breathing and noticeable breathing at rest. The habit of overbreathing causes a disturbance of blood gases, as well as cooling and drying of the airways resulting in symptoms such as coughing, wheezing and breathlessness.
Teaching a child or adult with asthma to switch to breathing through their nose, and bring their breathing volume towards normal, results in a significant reduction of asthma symptoms and improvement to quality of life. Furthermore, clinical trials investigating the Buteyko Breathing Method for asthma report that the improvement to asthma control from applying the Buteyko Breathing Method leads to almost half the need for inhaled steroid medication. There are currently nine published studies investigating the Buteyko Breathing Method as a treatment for asthma, including one study collaborated on by Patrick McKeown with the University of Limerick in Ireland. Click HERE to read trials.
In more detail:
Asthmatic airways are prone to constriction by a combination of inflammation, constriction of smooth muscle and increased secretions of mucus. Narrowing of the airways induces a feeling of a hunger for air, accelerating the respiratory rate and volume as a compensatory mechanism. The feeling that one is not getting enough air may also encourage a switch from nasal to mouth breathing.
While it is entirely logical that narrowing of the airways (bronchoconstriction) results in an increase to breathing volume, it is important to recognise that increased breathing volume contributes to bronchoconstriction. In other words, there is a feedback loop. The child or adult with asthma breathes too much because of the feeling of “air hunger” and this, in turn, feeds back into narrowing of the airways.
The following information examines the contributory role of chronic hyperventilation to asthma, and how the Buteyko Breathing Method can be used as a useful tool to empower people with asthma to take control of their condition naturally and safely.
While most medical textbooks list normal minute ventilation for a healthy adult of between 4 and 9 litres, individuals with asthma demonstrate resting ventilation of between 10 and 15 litres per minute.
Normal breathing during rest involves regular, silent diaphragmatic breaths drawn in and out through the nose. People with asthma on the other hand display habitual oral breathing, regular sighing and sniffing with visible movements from the upper chest. During an exacerbation of asthma, respiratory rate, wheezing and breathlessness all increase relative to severity.
According to researcher Hallani in a 2008 paper published in the European Respiratory Journal, people with asthma tend to switch to oral breathing more than individuals without asthma. Kairaitis supports this finding and notes that, asthmatics are more likely to breathe through their mouth, a factor which may contribute to the severity of their asthma. Mouth breathing also causes a reduction in lung function in mild asthmatics and plays a role in the pathogenesis of acute asthma exacerbations.
Practical examples of increased breathing volume causing asthma symptoms include laughter, stress and physical exercise. Laughter is often cited as the best medicine, although many people with asthma experience fits of coughing and wheezing following a good hearty laugh. In 2005, The American Thoracic Society published a paper entitled laughter induced asthma: It’s no joke. The authors found that laughter was the second most common trigger of asthma after exercise, affecting up to 56% of asthmatics. While the exact cause of the laughter induced asthma could not be determined, the authors cited hyperventilation as a possibility.
The large intake of air into the lungs during laughter may be causing a loss of carbon dioxide, or having a cooling or dehydration affect on the airways resulting in bronchoconstriction and airway sensitivity. In agreement, the 2012 GINA Global Strategy for Managing Asthma recognises that extreme emotional expressions such as “laughing, crying, anger and fear can lead to hyperventilation and hypocapnia that can cause airway narrowing.”
A number of researchers have determined an inverse relationship between length of breath hold time and breathing volume. Over the past fifteen years, Patrick McKeown has measured the comfortable breath hold time of thousands of individuals with asthma. Mild asthmatics consistently hold their breath for up to twenty seconds, moderate for fifteen seconds and severe for up to ten seconds. The measurement applied was developed by the Late Russian Dr Konstantin Buteyko and is known as the “control pause”.
Here is how you can measure your own “control pause”:
Measuring the Control Pause (Taken from the Buteyko Breathing Method)
- Take a small, silent breath in through your nose and allow a small silent breath out through your nose.
- Hold your nose with your fingers to prevent air from entering your lungs.
- Count the number of seconds until you feel the first distinct desire to breathe in.
- At the first distinct desire to breathe in, you may also feel the first involuntary movements of your breathing muscles. Your tummy may jerk and the area around your neck may contract.
- Your inhalation at the end of the breath should be calm.
- Release your nose and breathe in through it.
The premise of the control pause is that a lower breath hold time corresponds with a higher ventilation during rest and greater airway obstruction. Furthermore, each five second increase to the control pause corresponds to reduced exercise induced asthma, coughing, wheezing, breathlessness and chest tightness across all variants of asthma.
Similarly to Buteyko, Japanese researcher Nishino acknowledged breath holding as one of the most powerful methods to induce the sensation of breathlessness, and that the breath hold test gives us much information on the onset and endurance of dyspnea.
The Department of Physiotherapy at the University of Szeged, Hungary conducted a study that investigated the relationship between breath hold time and physical performance in patients with cystic fibrosis. Eighteen patients with varying stages of cystic fibrosis were studied to determine the value of the breath hold time as an index of exercise tolerance. The breath hold times of all patients were measured. The researchers found a significant correlation between breath hold time and VO2, concluding that the breath-hold time might be a useful index for prediction of the exercise tolerance of CF patients.
Results from another study of 13 patients with acute asthma concluded that the magnitude of breathlessness, breathing frequency and breath hold time correlated with severity of airflow obstruction and, secondly, that breath hold time varies inversely with the magnitude of (breathlessness) dyspnea when it is present at rest.
The first step to normalising breathing volume is to decongest the nose and make a permanent switch to nasal breathing. As chronic hyperventilation can be maintained by an occasional sigh, it is important to counteract the sigh by swallowing or holding the breath. The switch to nasal breathing is followed by employing breathing exercises designed to bring breathing volume towards normal.
The nose can be decongested for both allergic and non allergic rhinitis by holding the breath as follows:
- Take a small, silent breath in and a small, silent breath out through your nose.
- Pinch your nose with your fingers to hold your breath.
- Walk as many paces as possible with your breath held. Try to build up a large air shortage, without overdoing it of course!
- When you resume breathing, do so only through your nose; your breathing must be calmed immediately.
- After resuming your breathing, your first breath will usually be bigger than normal. Make sure that you calm your breathing as soon as possible by suppressing your second and third breaths.
- You should be able to recover this breath hold within two to three breaths. If you cannot, you have held your breath for too long.
- Wait for about a minute or so and then repeat.
- Repeat this exercise five or six times until the nose is decongested.
The above exercise formed part of a preliminary study at Limerick Regional Hospital ENT department which investigated the Buteyko Method for rhinitis in asthma patients. Results indicated a 75-80% improvement in nasal symptoms which persisted at 3 month follow-up as long as the patients continued with the exercises.
The nose performs significant functions including warming, humidifying and filtering incoming air. A high concentration of nitric oxide exists in the nasal airway, making it imperative to breathe through the nose. Breathing through the mouth bypasses the nose, resulting in a diminished role for nitric oxide. According to researcher Scadding, ‘nasal nitric oxide probably explains some of the benefit of nasal rather than mouth breathing’.
In the upper airways, nitric oxide provides a first line defence against microorganisms through antiviral and antimicrobial activity. In the lungs, it is involved in ventilation perfusion matching.
There are currently nine published studies investigating the Buteyko Breathing Method as a treatment for asthma, including the study collaborated on by Patrick McKeown with the University of Limerick. All studies concluded a significant improvement to asthma control with a number of trials showing a 70% reduction in the need for asthma reliever medication and a 50% reduction in the need for asthma steroid medication within 12 to 24 weeks. Click HERE to read trials.
In a paper published in the American Review of Respiratory Disease, researchers studied the beneficial effects of nasal breathing on exercise-induced asthma. The study observed that most asthmatic subjects spontaneously breathe with their mouths open when instructed to breathe ‘naturally’. The authors found that mouth breathing during exercise caused the airways to narrow. In contrast, when subjects were required to breathe only through their nose during exercise, exercise-induced asthma did not occur at all. The paper concluded that “the nasopharynx and the oropharynx play important roles in the phenomenon of exercise-induced bronchoconstriction”.
In another study, researchers Mangla and Menon studied the effects of nasal breathing and oral breathing on exercise-induced asthma. Fifteen people were recruited for the study. As in the previous study, participants were required to breathe only through their nose. The study found that ‘the post-exercise bronchoconstrictive response was markedly reduced as compared with the response obtained by oral (mouth) breathing during exercise, indicating a beneficial effect of nasal breathing’.
That elite athletes with asthma often favour swimming above other forms of exercise is not a coincidence. When swimming, the face is immersed underwater, serving to restrict breathing volume. Although the swimmer draws his or her breath in through the mouth, ventilation is less than when compared to running or cycling. Another beneficial factor from swimming is that the body’s weight on the water exerts gentle pressure on the chest and tummy, which further restricts breathing.
In the words of respiratory consultant Dr Peter Donnelly, ‘In most land based forms of exercise, patterns of breathing are not constrained, ventilation increases proportionately throughout exercise and end tidal CO2 tensions are either normal or low. Therefore, there is no hypercapnic stimulus for bronchodilation and asthmatics have no protection’.
Although the act of swimming is beneficial, spending time in chlorinated pools is not because chlorine can cause damage to lung tissue leading to swimming-related health hazards.
Breathing exercises aimed at normalising breathing volume have been attracting recent attention. The 2012 British Thoracic Society asthma guidelines state that the “Buteyko breathing technique may be considered to help patients to control the symptoms of asthma.”
Studies investigating the Buteyko Method for asthma showed improved asthma control with an 80% to 90% reduction in the need for bronchodilator medication, 50% less need for corticosteroids with no decrease to lung function.23, 24 In another trial, pulmonologist Professor Robert Cowie from the University of Calgary, Canada acted as independent investigator. Following the improvement to asthma control in the Buteyko group, he commented that “75% control is about as good as anyone has got in any study of asthma. The neat thing about it is that it has no side effects. It’s very safe. The Buteyko technique certainly has been shown to be an important adjunct to treatment.”
Buteyko courses can be taught to children over five years old, and all adults regardless of asthma severity. The importance of breathing through the nose and changing breathing volume towards normal is often overlooked in asthma management. Buteyko Clinic International provide resources to help persons apply the Buteyko Method easily and effectively for asthma. Books, DVD sets, courses and online skype consultations are available. For further information, contact us via our contact page.
For information about COPD (Chronic Obstructive Pulmonary Disease) and how the Buteyko Method can help, please click HERE.
- Ganong WF, Review of medical physiology, 15-th ed., 1995, Prentice Hall Int., London
- Johnson BD, Scanlon PD, Beck KC, Regulation of ventilatory capacity during exercise in asthmatics ,J Appl Physiol. 1995 Sep; 79(3): 892-901.
- Chalupa DC, Morrow PE, Oberdörster G, Utell MJ, Frampton MW, Ultrafine particle deposition in subjects with asthma Environmental Health Perspectives 2004 Jun; 112(8): p.879-882.
- Bowler SD, Green A, Mitchell CA, Buteyko breathing techniques in asthma: a blinded randomised controlled trial. Med J of Australia 1998; 169: 575-578
- GINA. GINA Report, Global Strategy for Asthma Management and Prevention. http://www.ginasthma.org/guidelines-gina-report-global-strategy-for-asthma.html (accessed 27 December 2012). Page 74
- 6) Hallani M, Wheatley JR, Amis TC. Initiating oral breathing in response to nasal loading: asthmatics versus healthy subjects. European Respiratory Journal.2008;(Apr;31(4)):800-6
- Kairaitis K, Garlick SR, Wheatley JR, Amis TC. Route of breathing in patients with asthma. Chest.1999;(Dec;116(6)):1646-52
- Hallani M, Wheatley JR, Amis TC. Enforced mouth breathing decreases lung function in mild asthmatics. Respirology.2008;(Jun;13(4)):553-8
- American Thoracic Society International Conference. Laughter-Induced Asthma: It’s No Joke. http://www.sciencedaily.com/releases/2005/05/050524230036.htm (accessed 27. Dec 2012).
- GINA. GINA Report, Global Strategy for Asthma Management and Prevention. http://www.ginasthma.org/guidelines-gina-report-global-strategy-for-asthma.html (accessed 27 December 2012). Page 64
- Nishino T. Pathophysiology of dyspnea evaluated by breath-holding test: studies of furosemide treatment. Respiratory Physiology Neurobiology.2009 May 30;(167(1)):20-5
- Barnai M, Laki I, Gyurkovits K, Angyan L, Horvath G. Relationship between breath-hold time and physical performance in patients with cystic fibrosis. European Journal of applied physiology.2005 Oct;(95(2-3)):172-8
- Pérez-Padilla R, Cervantes D, Chapela R, Selman M. Rating of breathlessness at rest during acute asthma: correlation with spirometry and usefulness of breath-holding time. Rev Invest Clin.1989 Jul-Sep;(41(3)):209-13
- Djupesland PG, Chatkin JM, Qian W, Haight JS. Nitric oxide in the nasal airway: a new dimension in otorhinolaryngology. Am J Otolaryngol.2001 Jan-Feb;(22(1)):19-32
- Professor John Fenton. (Limerick Regional ENT) Preliminary results. Email to: Patrick McKeown. (firstname.lastname@example.org) 2006
- Scadding G. Nitric oxide in the airways. 4) Curr Opin Otolaryngol Head Neck Surg..2007 Aug;(15(4)):258-63
- Vural C, Güngör A.. [Nitric oxide and the upper airways: recent discoveries]. Tidsskr Nor Laegeforen.2003 Jan;(10(1)):39-44
- Shturman-Ellstein R, Zeballos RJ, Buckley JM, Souhrada JF. The beneficial effect of nasal breathing on exercise-induced bronchoconstriction. American Review Respiratory Disease.1978;(Jul;118(1)):65-73
- Mangla PK, Menon MP. Effect of nasal and oral breathing on exercise-induced asthma. Clin Allergy.1981;(Sep;11(5)):433-9
- Donnelly Peter M . Exercise induced asthma: the protective role of Co2 during swimming. The Lancet.1991;(Jan 19;337(8734):):179-80
- Uyan ZS, Carraro S, Piacentini G, Baraldi E. Swimming pool, respiratory health, and childhood asthma: should we change our beliefs? Pediatr Pulmonol.2009 (Jan;44(1)):31-7
- British Thoracic Society. BTS/SIGN Asthma Guideline: 2011. http://www.brit-thoracic.org.uk/Portals/0/Guidelines/AsthmaGuidelines/sign101%20Jan%202012.pdf (accessed 27 December 2012).
- Bowler SD, Green A, Mitchell CA. Buteyko breathing techniques in asthma: a blinded randomised controlled trial. Medical Journal Australia .1998 Dec 7-21;(169(11-12)):575-8
- McHugh P, Aitcheson F, Duncan B, Houghton F.. Buteyko Breathing Technique for asthma: an effective intervention. The New Zealand Medical Journal.2003 Dec 12;():116(1187):U710
- BIBH. BIBH 2007 conference . www.BIBH.org (accessed 27 December 2012).
Copyright (c) Patrick McKeown 2013. All rights reserved. No reproduction or republication is permitted without written permission
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
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.
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.
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.
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.
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.
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
The use of mouth taping, to encourage nose breathing, is currently being recommended by some Buteyko practitioners, 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
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.
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