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O’Connor E, Patnode CD, Burda BU, et al. Breathing Exercises and/or Retraining Techniques in the Treatment of Asthma: Comparative Effectiveness [Internet]. Rockville (MD): Agency for Healthcare Research and Quality (US); 2012 Sep. (Comparative Effectiveness Reviews, No. 71.)
This publication is provided for historical reference only and the information may be out of date.
Breathing Exercises and/or Retraining Techniques in the Treatment of Asthma: Comparative Effectiveness [Internet].
Show detailsCondition Definition
Asthma is a chronic disorder of the airways characterized by the complex and variable interaction of underlying inflammation, bronchial hyper-responsiveness, and airway obstruction.1 Asthma’s principal symptoms result primarily from bronchoconstriction and a resulting reduction in airflow. These symptoms include shortness of breath, cough, wheezing, and chest pain or tightness. The associated reduction in airflow is usually reversible spontaneously or with treatment.1 The specific clinical manifestations and severity of asthma can vary among and within susceptible individuals. Asthma further varies in its chronicity, cellular pathophysiology, triggers, and responsiveness to medication.
Prevalence and Disease Burden
In 2009, the estimated prevalence of asthma in the United States was 8.2 percent, representing 24.6 million adults and children. The prevalence was 9.6 percent among children and 7.7 percent among adults.2
The prevalence of asthma has increased substantially during the past 30 years. While it is difficult to compare exact prevalence figures over this period due to changes in surveillance methods, it appears that the prevalence has roughly doubled in most age, sex, and race subgroups.3 Asthma is also more common among people of certain ethnic and racial groups, with Puerto Ricans, African Americans, American Indians, and Alaska Natives having the highest prevalence rates.4 In addition, the prevalence of asthma is highest among people of low socioeconomic status.4
When poorly controlled, asthma is associated with increased health care use, decreased quality of life, and significant activity limitations.5,6 In 2007, asthma accounted for 456,000 hospitalizations and 3,447 deaths in the United States.2 The morbidity associated with asthma adds to the costs incurred by both patients and health care organizations. In the United States, the projected annual cost (direct and indirect) of asthma in 2010 was estimated to be over $20 billion.3
Etiology and Natural History of Asthma
Our knowledge of the pathogenesis of asthma has evolved over the past 25 years from a primary focus on bronchospasm to an understanding of the role of airway inflammation. We currently describe these processes along a continuum that includes severe persistent disease resulting from airway remodeling due to chronic inflammation.1 The onset of asthma can occur at any age and the disease may or may not persist.7 While causes of childhood asthma are not well understood, we do know that children who develop asthma are more likely to have mothers with asthma, have increased airway resistance, have allergic sensitization by 3 years of age,8 and are atopic (especially if the atopy is accompanied by high levels of exposure to perennial allergens early in life).9 Although the definitive etiology or etiologies of adult-onset asthma have not been identified, it is estimated to be work-related in 11 to 50 percent of cases, depending on age and sex.10
The clinical course of asthma is largely unpredictable and is widely variable. The progression of asthma appears to vary in different age groups, as measured by pulmonary function.1 In children, deficits in pulmonary function growth appear to generally occur by the age of 6 years, and primarily in those whose symptoms began before the age of 3 years. In adults, there is evidence that pulmonary function may progressively decline, but the implications of this decline for the development of fixed airflow obstruction are not understood.1
Diagnosis and Assessment of Asthma
Diagnosing and assessing asthma requires clinical judgment based on medical history, physical examination, and pulmonary function testing.1 Guidelines from an expert panel recommend that before establishing a diagnosis of asthma a clinician should determine that: (a) episodic symptoms of airflow obstruction or airway hyperresponsiveness are present; (b) airflow obstruction is at least partially reversible; and (c) alternate diagnoses are excluded.1 Because other diagnoses cannot be reliably excluded by medical history and physical examination, and because patients vary considerably in their ability to perceive of airflow obstruction, an objective assessment of pulmonary function is necessary for an asthma diagnosis. While peak expiratory flow (PEF) meters are useful for monitoring the disease, spirometry is more reliable and recommended for establishing the diagnosis.1 Guidelines recommend assessing forced expiratory volume for 1 (FEV1) or 6 seconds and/or forced vital capacity (FVC, the total volume of air that can be forcibly exhaled after maximal inhalation) before and after use of a short-acting bronchodilator. Maximal patient effort during spirometry testing is crucial for accurate assessment. A skilled technician who adheres to American Thoracic Society (ATS) performance guidelines is also important.11
Airway obstruction is considered reversible if there is an increase in FEV1 of more than 200 milliliters and 12 percent from baseline after two to four puffs of albuterol. In patients who are not taking long-term control medications (e.g., inhaled corticosteroids [ICS]), an FEV1 below 60 percent of predicted (based on age and sex) is categorized as “severe” asthma, 60 to 80 percent of predicted is “moderate,” and above 80 percent is “mild.”
Distinguishing severity of underlying disease from current control is important in characterizing asthma. Asthma severity is the intrinsic intensity of the disease. Asthma control is the degree to which symptoms and functional limitations are minimized (e.g., a person may have severe underlying disease that is well controlled). Severity is assessed before introduction of long-term controller medications such as inhaled corticosteroids. Once therapy is initiated, asthma control is monitored and treatment modifications are based on degree of control.
Treatment of Asthma
As our understanding of the critical role played by inflammation in the pathophysiology has increased, so has the number of therapies targeting this inflammatory process. In addition to short-acting beta2-agonist (SABA) drugs for quick-relief of acute exacerbations, pharmacologic treatment of persistent asthma often entails the use of anti-inflammatory medications for long-term control — most commonly ICS, but also including drugs that target various inflammatory cell types, such as leukotriene modifiers (see Appendix A for an overview of medications recommended for use in treating asthma).1
The goal of treatment is to achieve asthma control, as evidenced by normal or near normal pulmonary function, maintenance of normal activity levels, and minimal need for SABA inhalers for “quick-relief” of asthma symptoms (≤ twice per week).1 Asthma treatment is often multifocal and tailored to the individual’s characteristics, including disease pattern and severity, treatment response, and side effects. Current U.S. guidelines recommend four essential components for effective asthma management: assessing and monitoring the disease, self-management education, controlling environmental and co-morbid conditions, and adequate pharmacologic therapy. Although treatment seeks to improve asthma control, treatment does not appear to affect the underlying severity of the asthma, at least in adults.1
Despite clinical practice guidance on self-management education and medication use, many patients with asthma appear to adhere poorly to such recommendations.12,13 Studies have found that adults with asthma and the parents of children with asthma have concerns about regular use of medication, including fears of long-term dependence and side effects associated with inhaled and oral steroids.14,15 While side effects for ICS are rare, these medications can be associated with a number of possible side effects, including slowed growth in children. However, effects on growth are small, appear to be seen primarily in the first months of treatment, are generally nonprogressive, and may be reversible. On the other hand, poorly controlled asthma can also delay growth in children.
At high doses and with long-term use, ICS use can be associated with adrenal suppression, osteoporosis in adults, skin thinning/easy bruising, and possibly the increased risk of developing cataracts in adults and glaucoma in adults with a family history of glaucoma.1 In addition, according to the product information insert for QVAR® 40 micrograms (mcg) and 80 mcg, long-term effects of chronic ICS use are still not fully known, including effects on the immunologic processes in the mouth, pharynx, trachea, and lung.16 Possible side effects of SABAs include headache, musculoskeletal pain, tachycardia, and other cardiovascular effects. In addition, there have been rare reports of serious, even fatal, asthma exacerbations associated with overuse of SABAs, particularly older versions of these medications (isoproterenol and fenoterol).17
A variety of complementary and/or alternative therapies have been advocated for the control of asthma given its spectrum of severity and causes as well as concerns about long-term medication use. These include breathing exercises, herbal remedies, homeopathy, acupuncture, relaxation therapies, and manual therapy (e.g., chiropractic techniques, massage). Breathing retraining exercises are among the complementary and alternative treatments most frequently used by people with asthma, and are purported to have virtually no adverse effects.14,18,19 Breathing retraining is generally assumed to be complementary to guideline-based care, with the primary goals of improving asthma control and reducing the use of medications, particularly SABAs. Some specific breathing retraining approaches include the Buteyko breathing technique, yoga-based approaches, and other physical therapy techniques. In the United States, 27 percent of children with asthma reported some use of complementary and alternative medicine (CAM).20 Among those, 58 percent reporting using some sort of breathing technique to help manage asthma, which was the most common type of CAM used. The study did not provide more detail regarding the specific type of breathing exercises used, and since only 8.4 percent of the children reported using practitioner-based CAM, likely most of the children using these techniques are not involved in rigorous or supervised breathing training.
Buteyko and Other Methods Based on Hyperventilation Reduction and Carbon Dioxide Regulation
The Buteyko breathing technique, developed by Konstantin Buteyko, is based on the theory that chronic hyperventilation in people with asthma leads to decreased carbon dioxide (CO2) in the blood (hypocapnia), which constricts the airways. Buteyko developed a breathing method to increase the amount of CO2 in the blood. This method involves controlled shallow breathing through the nose only, with breath-holding at the end of the exhalation. The length of time a person is able to hold their breath at the end of an exhalation indicates the extent of hyperventilation, with longer periods of breath-holding indicating less hyperventilation.21 Buteyko practitioners also train users to eliminate or minimize sighs, yawns, and gasps, which they consider “overbreathing.” This method requires commitment on the part of users, since it usually takes considerable practice to master. When experiencing asthma symptoms, Buteyko users are encouraged to utilize breathing the technique for 5 to 10 minutes before using a bronchodilator to relieve symptoms. Buteyko practitioners encourage the use of porous tape to hold the lips together at night for those who tend to breathe through their mouths at night. The British Thoracic Society (BTS) guideline developers concluded that evidence supported consideration for the use of the Buteyko breathing technique to control the symptoms of asthma.22
Other clinicians have used approaches not specifically identified as Buteyko breathing training, but are consistent with Buteyko methods and/or integrate Buteyko methods. For example, the Papworth method involves instruction in slow (e.g., 8 breaths per minute), steady diaphragmatic breathing through the nose, with a pause at the end of each breath and elimination of sighs and other overbreathing. In addition, they work with patients to teach them to use relaxed, controlled breathing while talking and engaging in daily activities.23,24
The evidence supporting the hyperventilation theory of the pathophysiology of asthma is mixed. One study showed that people with asthma have lower end-tidal CO2 levels (i.e., blood levels of CO2 at the end of exhalation) than those without asthma.25 Research by ven den Elshout and colleaguesappears consistent with Buteyko’s theory by demonstrating that inducing a reduction in end-tidal CO2 levels increased airway resistance in people with asthma and a history of bronchial hyperresponsiveness to histamine, but it did not change airway resistance in matched controls without asthma.26 When hypercapnia (high level of CO2 in the blood) was induced in the same study, airway resistance decreased in both patients with asthma and controls.26 Another study, however, found that longer breath-holding time was associated with a reduction in end-tidal CO2, which is counter to Buteyko’s theory.27
Yoga-Based Approaches
The breathing techniques used in yoga, known as pranayama, are integral to virtually all yoga traditions. While these traditions vary in the specific use of breathing techniques, they generally involve slowing and regularizing the breath by prolonging the expiratory phase, enhancing abdominal/diaphragmatic breathing, and imposing resistance to both inspiration and exhalation.28 The prolonged expiratory phase is assumed to promote mental and physical relaxation. Increased respiratory resistance, which can be achieved through manually blocking one nostril or by using the tongue and other mouth muscles to narrow breathing passages, is thought to promote efficient alveolar gas exchange and, in asthma patients, to help reduce hyperinflation of the lungs. Like hyperventilation reduction methods, yoga practitioners usually advocate the use nasal breathing rather than mouth breathing, and both approaches appear to have the effect of slowing the passage of air in and out of the lungs. It is unclear if the two approaches have similar physiologic effects.
Physical Therapy Techniques and Inspiratory Muscle Training
Slow-paced respiration provides users with an external stimulus to encourage a specific (slow) breathing rate. Slower breathing rates have been associated with lower stress response (as measured by skin resistance, finger pulse volume, and self-reported anxiety in the face of anticipated stressors). Slow-paced respiration is typically combined with abdominal breathing to reduce panic attacks, and thus may be of help to the extent that asthma is triggered by stress or anxiety.29 Biofeedback has been used to indirectly target airway resistance by increasing heart rate variability (HRV), and has also been used to directly target airway resistance via the relaxation of the muscles used for breathing.29 Biofeedback uses electronic monitoring devices to show a participant some kind of physiologic level (such as HRV or muscle tension) in order to teach him or her to control bodily functions that normally happen automatically. Training to increase HRV involves feedback to increase the amplitude of the heart rate oscillations with breathing.30 Participants may be instructed in cognitive strategies and/or slow abdominal/diaphragmatic breathing as a means for increasing HRV,31 though the specific mechanism of action is unknown.30
Another set of physical therapy techniques may be used to strengthen inspiratory and/or expiratory muscles to help reduce perception of dyspnea, aid in overcoming airway resistance, and avoiding hyperinflation due to insufficient expiratory strength.
Scope and Purpose
The original public nomination made by a Buteyko practitioner and physical therapist requested a review focused specifically on the effectiveness of the Buteyko method for reducing bronchodilator and inhaled steroid use and improving the health status of adults and children with asthma. After input from experts and consulting the literature, we expanded the topic to also address the breathing retraining approaches described above. Thus, the objective of this review is to synthesize the data on the effectiveness and comparative effectiveness of a variety of breathing retraining techniques in the management of asthma in adults and children 5 years of age or older.
Key Questions
Three systematically reviewed Key Questions are addressed in this report. These questions address the impact of breathing exercises on health outcomes and pulmonary function in addition to the harms related to breathing exercises in the treatment of asthma.
- In adults and children 5 years of age and older with asthma, does the use of breathing exercises and/or retraining techniquesa improve health outcomes, including: symptoms (e.g., cough, wheezing, dyspnea); health-related quality of life (general and/or asthma-specific); acute asthma exacerbations; reduced use of quick-relief medications or reduced use of long-term control medications, when compared with usual care and/or other breathing techniques alone or in combination with other intervention strategies?
- Does the efficacy and/or effectiveness of breathing techniques for asthma health outcomes differ between different subgroups (e.g., adults/children; males/females; different races or ethnicities; smokers/nonsmokers; various types and severities of asthma; and/or different coexisting conditions)?
- Does the efficacy and/or effectiveness of breathing techniques for asthma health outcomes differ according to variations in implementation (e.g., trainer experience) and/or nonbreathing components of the intervention (e.g., anxiety management)?
- In adults and children 5 years of age and older with asthma, does the use of breathing exercises and/or retraining techniques improve pulmonary function or other similar intermediate outcomes when compared with usual care and/or other breathing techniques alone or in combination with other intervention strategies?
- Does the efficacy and/or effectiveness of breathing techniques for other asthma outcomes differ between different subgroups (e.g., adults/children; males/females; different races or ethnicities; smokers/nonsmokers; various types and severities of asthma; and/or different coexisting conditions)?
- Does the efficacy and/or effectiveness of breathing techniques for other asthma outcomes differ according to variations in implementation (e.g., trainer experience) and/or nonbreathing components of the intervention (e.g., anxiety management)?
- What is the nature and frequency of serious adverse effects of treatment with breathing exercises and/or retraining techniques, including increased frequency of acute asthma exacerbations?
- Do the safety or adverse effects of treatment with breathing techniques differ between different subgroups (e.g., adults/children; males/females; different races or ethnicities; smokers/nonsmokers; various types and severities of asthma; and/or different coexisting conditions)?
Footnotes
- a
For example: the Buteyko breathing technique; inspiratory muscle training (IMT); breathing physical therapy including paced and pursed lip breathing exercises; the Papworth method; biofeedback- and technology-assisted breathing retraining; and yoga breathing exercises.
- Introduction - Breathing Exercises and/or Retraining Techniques in the Treatment...Introduction - Breathing Exercises and/or Retraining Techniques in the Treatment of Asthma: Comparative Effectiveness
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