|Year : 2017 | Volume
| Issue : 2 | Page : 61-68
Improvement in pulmonary functions and clinical parameters due to addition of breathing exercises in asthma patients receiving optimal treatment
Dipti Agarwal1, Prem Parkash Gupta2, Sushma Sood1
1 Department of Physiology, Post Graduate Institute of Medical Sciences, Pt. B D Sharma University of Health Sciences, Rohtak, Haryana, India
2 Department of TB and Respiratory Medicine, Post Graduate Institute of Medical Sciences, Pt. B D Sharma University of Health Sciences, Rohtak, Haryana, India
|Date of Web Publication||29-Sep-2017|
Prem Parkash Gupta
Department of TB and Respiratory Medicine, Post Graduate Institute of Medical Sciences, Pt. B. D. Sharma University of Health Sciences, Rohtak, Haryana
Source of Support: None, Conflict of Interest: None
Background: Breathing exercises have been described to be useful in asthma management.
Objective: The aim of this study is to detect the efficacy of breathing exercises (Pranayamas) in asthma patients using spirometric indices, clinical symptoms parameters, and requirement of rescue medications.
Methods: A total of 60 stable asthma patients (34 females) diagnosed and received optimal asthma treatment for 3 months or more according to the GINA guidelines were enrolled. All patients continued their respective medications and in addition performed seven breathing exercises (Surya Bhedana Pranayama, Nadi Shuddi Pranayama, Bhramari Pranayama, Surya Nadi Pranayama, Kapal Bhati, Bhastrika, and Om Chanting) under supervision at Yoga center at our Institute for 3 months after inclusion to study. Spirometry, nocturnal symptoms, and the requirement of rescue medicines were assessed before and after breathing exercise intervention. Visual analog scale (VAS) was used to assess the dyspnea and wheezing in the study participants.
Results: The mean age of asthma patients was 25.45 ± 5.41 years. After breathing exercise intervention, mean forced expired volume in one second increased from 2.492 ± 0.358 L to 2.745 ± 0.343 L and mean peak expiratory flow rate increased from 283.82 ± 51.12 L/min to 336.23 ± 51.47 L/min; the increases were statistically significant. The mean nocturnal symptoms score decreased significantly from 1.416 ± 1.619 to 0.067 ± 0.362. The requirement of rescue medications decreased significantly from 6.23 ± 2.95 to 0.90 ± 1.25 puffs/week. VAS scores for breathlessness and wheezing were significantly decreased.
Conclusions: Breathing exercises provided significant improvements in spirometric parameters and significant reduction in breathlessness, wheezing, and nocturnal symptoms as well as requirements of rescue medicines in asthma patients who were receiving optimal asthma treatment.
Keywords: Alternative therapy, asthma, breathing exercises, clinical assessment, Pranayamas, pulmonary functions
|How to cite this article:|
Agarwal D, Gupta PP, Sood S. Improvement in pulmonary functions and clinical parameters due to addition of breathing exercises in asthma patients receiving optimal treatment. Indian J Allergy Asthma Immunol 2017;31:61-8
|How to cite this URL:|
Agarwal D, Gupta PP, Sood S. Improvement in pulmonary functions and clinical parameters due to addition of breathing exercises in asthma patients receiving optimal treatment. Indian J Allergy Asthma Immunol [serial online] 2017 [cited 2017 Oct 22];31:61-8. Available from: http://www.ijaai.in/text.asp?2017/31/2/61/215840
| Introduction|| |
Asthma, usually characterized by chronic airway inflammation, is a heterogeneous disease. It is defined by the history of respiratory symptoms such as wheeze, shortness of breath, chest tightness, and cough that vary over time and in intensity, together with variable expiratory airflow limitation. There is a huge global burden of asthma, the later affecting 300 million people and with 250,000 annual deaths - most of which are preventable. According to ISAAC Group, asthma, rhinitis, and eczema in children are increasing in western and developing countries and the prevalence of wheeze varies widely. The rate of asthma increases as communities adopt western lifestyles and become urbanized. The gap between varied prevalence is now closing, due to a rise in prevalence in low- and middle-income countries and plateauing in high-income countries. According to Global Burden of Asthma Report by GINA, with the anticipated increase in the proportion of the world's population that is urban from 45% to 59% in 2025, a marked increase in the number of asthmatics worldwide is projected over the next decades.
Asthma is a chronic health problem that usually encompasses the patient's entire lifetime affecting pulmonary functions and with chronic symptoms.,, It has been documented that the quality of life impairment in asthma patients is often related to the severity of disease. A recent US study found adolescents with asthma and symptoms reported worse health-related quality of life compared with those with asthma but not reporting symptoms and those without asthma. Rational asthma management leads to disease control characterized by a decrease in symptoms, decrease in emergency department visits for asthma exacerbations, and decrease in rescue medicines required to ameliorate the asthma symptoms. In the present study, clinical and spirometric parameters were used to assess the advantage of seven breathing exercises, Pranayamas, when added to regular optimal medications, in asthma patients in achieving better asthma control.
| Methods|| |
Place of study
This study was carried out at the Departments of Physiology and Respiratory Medicine at our Institute. The patients were diagnosed at Respiratory Medicine outpatient at our institute, where the clinical care was provided. For the purpose of breathing exercises intervention, the patients attended Yoga Center in the Department of the Physiology.
Study subjects and inclusion criteria
The diagnosis of asthma was based on clinical symptoms and presence of variable expiratory airflow limitation as per the GINA guidelines. The clinical features considered for asthma diagnosis included: (i) Presence of any one or more symptoms of wheeze, shortness of breath, cough, and chest tightness, (ii) symptoms worsening during night or in the early morning, (iii) symptoms varying over time and intensity, (iv) symptoms triggered by viral infection, exercise, allergens, change in weather, laughter, or irritants such as smoke, fumes, or strong smells. The diagnosis of asthma in patients with these clinical characteristics was confirmed by co-existing airflow obstruction over spirometry that was reversible. An increase in forced expiratory volume in first second during forced expiratory maneuver (forced expired volume in one second [FEV1]) by 200 ml or more than 12% of baseline value on repeat spirometry 20 min after inhalation of 200 mcg of levosalbutamol given through a metered dose inhaler attached to a spacer was considered diagnostic of reversible air flow obstruction as per the American Thoracic Society guidelines. All the study participants were residing in close vicinity within 15 km from our Institute. Patients with any cardiovascular complication were excluded from the study.
The asthma patients included to study had a prior regular follow-up for the past 6 months and had no hospitalization due to asthma exacerbation during this period. The study patients had regular follow-up visits to the clinical department not less than once in a month with an assessment of their clinical course, relevant laboratory, and spirometric evaluation. The study required a stable course for 3 months preceding to study intervention and medicines in each patient was optimized and continued during this period. The same individualized medicines were continued during the study with breathing exercises intervention.
As per study protocol, all patients continued with their optimum individualized medication throughout the study period. Before inclusion to this study, the subjects received detailed instructions regarding these exercises for 1 week, and more when they desired, to make the subjects acquainted with nature and strenuosity of the exercises and to assess their willingness for consent to study. After inclusion to study, the study participants performed breathing exercises daily in front of instructor for a week and thereafter, until completion of 3 months, thrice a week on alternate days in front of instructor and on rest of 4 days per week at home but with full support and understanding to attend the instructor for further supervisions. All subjects maintained the diary for recording the duration and timing of the exercises and also to record the symptoms.
The seven breathing exercises assessed in the present study were standard Pranayamas [Box 1]; the detail techniques are widely available in books, and well known to all Yoga instructors - a point essential to reproduce the study by any other researcher. The breathing exercises included: Surya Bhedana Pranayama, Nadi Shuddi Pranayama, Bhramari Pranayama, Surya Nadi Pranayama, Kapal Bhati, Bhastrika, and Onkar Pranayama/Om Chanting.
All study participants were assessed for asthma control status by carrying out before and after breathing exercise intervention - both objective parameters, including spirometry and subjective parameters, including visual analog scales (VAS) for dyspnea and wheezing, nocturnal asthma symptoms and the use of inhaled levosalbutamol metered dose inhaler as rescue medication.
The pulmonary function tests were carried out on Vitalograph-Compact (UNISSI - India Pvt. Limited). Spirometric indices were recorded as per the ATS guidelines  after performing three technically satisfactory performances. The following parameters were used for analyses: (i) Peak expiratory flow rate (PEFR) in L/min, (ii) FEV1 in L, (iii) forced vital capacity (FVC) in L, and (iv) FEV1/FVC ratio.
Assessment of the use of rescue medications
All subjects continued their optimal medication throughout the entire study period that was predetermined before starting the study intervention. They were allowed to use levosalbutamol sulfate (50 mcg/puff) metered dose inhaler as rescue medications if they had any exacerbation of symptoms; they were maintaining the record of the same in a Diary. Average of use of rescue medications for 7 days before starting the study intervention and during the last 7 days of study intervention period were evaluated for analysis purpose.
Assessment of the clinical symptoms
Asthma symptoms, including wheezing, shortness of breath, and nocturnal coughing were assessed before starting the study intervention and during the study intervention period; they were maintaining the record of the same in a diary. Average of Asthma symptoms for 7 days before starting the study intervention and during the last 7 days of study intervention period were evaluated for analysis purpose.
Visual analog scale
Breathlessness or dysnpea is the sum of physiological and psychological factors that is often difficult to measure. Continuous scales, such as VAS provide a more flexible mean of grading dyspnea and wheezing by utilizing patients' own perception regarding the severity of illness. Measurement of VAS levels is able to discriminate between patients with “controlled,” “partly controlled,” and “uncontrolled” asthma. The VAS score could be a simple guide in clinical situations requiring daily or regular evaluation of asthma control. In the present study, VAS was used to assess the dyspnea and wheezing.
| Results|| |
In present study, a total of 60 asthma patients were included. There were 34 female and 26 male asthma patients. Each patient had diagnosed asthma for 2 or more years and taking individualized medications as per GINA guidelines with a persistent but clinically stable course. Within 6 months preceding study period, none of the patients had any episode of asthma exacerbation and there was no hospitalization for asthma related illness. All patients were non-smokers. All patients were attending the institute with regular follow-up with adequate compliance to medications advised.
A detailed clinical evaluation was done in each subject prior to inclusion to study. The baseline characteristics of the patients are described in [Table 1]. Their mean age was 25.45 ± 5.41 year, mean FEV1 was 2.492 ± 0.358 L, mean FVC was 3.751 ± 0.482 L, FEV1/FVC ratio was 66.43 ± 4.039 and mean PEFR was 283.82 ± 51.12 L/min. Each of the study subjects recruited to the study was able to carry out the scheduled breathing exercises under supervision as per study protocol. None of the subjects had any acute exacerbation of asthma during the study period; there was no emergency department visit or any hospitalization due to asthma during this period. There was no drop-out from the study.
|Table 1: Patients' baseline characteristics at the time of inclusion to study|
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The study variables including spirometric indices, nocturnal symptoms, VAS for breathlessness and wheezing and the requirements of the rescue medication in study subjects before and after the breathing exercises intervention are shown in [Table 2]. There was statistically significant and clinically relevant improvement in FEV1 after breathing exercises intervention. FEV1/FVC ratio also increased significantly. PEFR increased from 283.82 ± 51.12 L/min to 336.23 ± 51.47 L/min; this increase was statistically significant and clinically relevant.
|Table 2: Changes in study parameters after breathing exercises intervention|
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There was significant reduction in asthma symptoms after breathing exercises intervention. Nocturnal symptoms score decreased from 1.416 ± 1.619 to 0.067 ± 0.362. Similarly a highly significant reduction was seen in VAS for breathlessness and VAS for wheezing. All this suggest clinically significant improvement with respect to asthma symptoms. As expected, with reduction in asthma symptoms and no exacerbation during study intervention period requirement of rescue levosalbutamol puff decrease from 6.233 ± 2.948 puff/week to 0.901 ± 1.245 puff/week suggesting a better control of asthma.
We also analyzed for correlations between baseline spirometric indices and the changes in study parameters [Table 3]. Decline in nocturnal symptoms score (suggestive of improvement in asthma) was directly correlated with all baseline spirometric indices. Decline in uses of rescue medications correlated with baseline FEV1/FVC ratio only. The change in FEV1 inversely correlated with baseline FEV1 and FEV1/FVC ratio. The change in FEV1/FVC ratio was inversely correlated with all baseline spirometric indices.
|Table 3: Correlations between changes in study parameters after breathing exercise intervention and the baseline spirometric indices|
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6] graphically display the improvement in FEV1 and FVC, rise in FEV1/FVC ratio, increase in PEFR, reduction in nocturnal symptoms, improvement in breathlessness and wheezing, and decline in uses of rescue bronchodilator medicine as a result of breathing exercise intervention, respectively.
|Figure 1: Improvement in forced expiratory flow in one second and forced vital capacity after 3 months breathing exercises intervention. 1 = Before breathing exercise intervention, 2 = After breathing exercise intervention|
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|Figure 2: Improvement in forced expiratory flow in one second/forced vital capacity ratio after 3 months breathing exercises intervention. 1 = Before breathing exercise intervention, 2 = After breathing exercise intervention|
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|Figure 3: Improvement in peak expiratory flow rate after 3 months breathing exercises intervention. 1 = Before breathing exercise intervention, 2 = After breathing exercise intervention|
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|Figure 4: Reduction in nocturnal symptoms after 3 months breathing exercises intervention. 1 = Before breathing exercise intervention. 2 = After breathing exercise intervention|
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|Figure 5: Improvement in breathlessness and wheezing after 3 months breathing exercises intervention. 1 = Before breathing exercise intervention. 2 = After breathing exercise intervention|
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|Figure 6: Reduction in use of rescue medicines after 3 months breathing exercises intervention. 1 = Before breathing exercise intervention, 2 = After breathing exercise intervention|
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| Discussion|| |
Last few decades have seen remarkable increase in our understanding regarding the pathogenesis and disease course in asthma leading to significant enhancement of medications armamentarium. Though a wide variety of highly effective inhaled and oral pharmacological options for the treatment of asthma are available now than ever, the prevalence of asthma continues to increase and also projected to further rise in near future. Many controlled clinical trials have reported asthma patients achieving high levels of control with available pharmacotherapy. However, recent assessments have shown that the optimism was unwarranted; asthma is incurable, and outcomes are not improving as expected. In clinical practice, poor control of asthma is common with over-reliance over rescue bronchodilator medication and patients continue to suffer from ongoing symptoms and quality-of-life impairment. Surveys have shown that a vast majority of people with asthma experience regular symptoms  resulting in an impaired ability to lead a full productive life and a huge direct and indirect costs. As the normal course of the disease is often characterized by recurrent episodes even with the best medications available, the major focus needs to be shifted to improve quality of life and the psycho-social well being of asthma patients by reducing the symptoms and airflow obstruction. The search for additional element to treat asthma may provide scope for non-pharmacological strategies like breathing exercises, allergen avoidance, life-style changes etc., that we could make use of to help our patients cope better and to reduce the impact of asthma on their lives.
Breathing exercises have been practiced for hundreds of years in both eastern and western societies for numerous medical conditions including asthma. Collective evidence from the traditional practice of yoga and other similar physical therapies frequently indicates an improvement and sometimes elimination of asthma symptoms. With the introduction of any new pharmacological molecule with patent for control of asthma, pharmaceutical companies readily provided study trial grants to authenticate their medicines for obvious commercial uses and, probably, due to lack of incentives, research in non-pharmacological elements remained deprived.
The efficacy of breathing exercises over asthma outcome has been assessed by few studies with small sample size in past. There had been wide variations across different trials in terms of type of breathing exercise assessed, study subjects included, procedural differences, variations in efficacy parameters and outcomes of data. The outcomes that have been measured often include quality of life, asthma symptoms, number of acute exacerbations and lung function. Three different breathing techniques have been more frequently used in these studies: Buteyko method, Papworth method, and Pranayamas.
The Buteyko method is based on the concept that asthma is linked to undiagnosed hyperventilation. The British Thoracic Society stated the Buteyko method may be considered to help patients control the symptoms of asthma while recognizing a paucity of data showing an objective improvement in prior studies. Papworth Method recommends a specific diaphragmatic breathing technique which is taught to replace the use of inappropriate accessory muscles of respiration. During relaxing state, emphasis is placed on calm slow nasal expiration.
The word Pranayama is considered to be originated from two Sanskrit words: Prana = life force. Yama = control, or mastery, thus signifying control of life force. Sri Patanjali is credited with compiling the Yoga Sutras and he is considered as the “Father of Yoga,” Yoga at present has international followers and has become a transnational world practice. The first International Yoga Day was observed on 21th June, 2015 (the longest day of the year in northern hemisphere) that was endorsed by United Nations General Assembly; the same is being repeated annually. The renewed public interest in Yoga and other therapies is apparent by the significant proliferation of self-help books and an increase in the demand for complementary therapies.
There have been few earlier studies that have assessed for the benefits of Pranayama or breathing exercises in asthma. One study by Nagarathna and Nagendra included 53 study subjects of asthma; this study found significantly greater improvement in the group who practiced yoga in term of reduction in weekly number of attacks of asthma, scores for drug treatment, and increase in peak flow rate.
In another study, yoga training was given for a short duration of seven days to 9 bronchial asthma patients. Even with this short yoga intervention, there was a reduction in sympathetic reactivity and an improvement in the pulmonary ventilation probably as a result of relaxation of voluntary inspiratory and expiratory muscles. This study observed that changes in life style based on yoga training had significant benefits even within a short period.
One study included patients with bronchial asthma and had deep breathing intervention, Brahmari, Anuloma viloma and Omkara in 25 study subjects along with 25 subjects in control group. They observed significant improvement in symptoms, FEV1 and PEFR. Few other studies ,, have also reported the beneficial effect of various Pranayamas breathing exercises in management of asthma, though various studies differ regarding study subjects, study interventions, and outcome measures.
The data from present study suggest a decline in asthma symptoms, improvement in pulmonary functions and decline in requirement of rescue medications for asthma in study subject due to breathing exercises intervention that was added to optimal pharmacological medications in asthma patients. None of the study subjects experienced any exacerbation during study intervention.
In addition to physiological improvement in term of reorganization of the respiratory muscles observed with breathing exercise, various psychological factors are also seem to be modified in asthma patients with breathing exercise that alter the perception of the patients towards limitations of physical activities and a better cope with symptoms. Goyeche et al. claimed that the psychosomatic imbalance is present in many, if not all patients with asthma. Suppressed emotion, dependence, anxiety, and extreme self-consciousness may all be accompanied by generalized and localized muscle tension, including that of the voluntary respiratory musculature. Modification of vagal efferent activity seems to affect the calibre of airways and may alter the effects of pharmacological stimuli on the airways. The role of the psychic factor in inducing or prolonging attacks during acute exacerbations may vary from patient to patient and in an individual patient from episode to episode.
Cochrane review (2013) observed that there were few high-quality studies looking at the efficacy of treating asthma with breathing retraining methods and observed that no reliable conclusions could be determined based on limited available evidence at that time. This review concluded that, while there are insufficient data for firm conclusions about efficacy, there is enough evidence to justify further trials. Many studies that have evaluated breathing retraining have some methodological flaws apart from having small sample sizes; these studies are hampered by the lack of proper blinding for obvious reasons and placebo control which could have introduced some bias into these studies. As a result of substantial heterogeneity among the studies, meta-analysis was possible only for asthma symptoms and changes in the Asthma Quality of Life Questionnaire and showed a significant improvement with breathing exercises. The reviews noted these techniques should only be used as adjuncts to conventional pharmacotherapy for symptom control. The British Thoracic Society stated that the Buteyko method might be considered to help patients control the symptoms of asthma while recognizing the lack of data showing an objective improvement in prior studies. The guideline also grades clinical research on Buteyko with a “B” classification – indicating that high quality supporting clinical trials are available.
Recently, an expert group guideline by the global initiative for asthma noted that breathing exercises may be a useful supplement to asthma pharmacotherapy. It has been suggested that improvement in symptoms by breathing exercises may be due to causes other than changes in the underlying physiology of the disease and include such as relaxation, voluntary reduction in medication use and increased participation of the patient in their own care. The data from various studies suggest that patients who experience anxiety or who overuse their rescue inhalers may expect benefit from breathing techniques as an adjunct to conventional treatments. Whatever may be the underlying cause for improvement, the finding that something has made patients feel better means we should not ignore this option. However, at present, the supervisory breathing exercises are not available in many parts of the world, and even if available, the cost of using these techniques may be prohibitive.
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Conflicts of interest
There are no conflicts of interest.
| References|| |
Reddel HK, Bateman ED, Becker A, Boulet LP, Cruz AA, Drazen JM, et al.
Asummary of the new GINA strategy: A roadmap to asthma control. Eur Respir J 2015;46:622-39.
Croisant S. Epidemiology of asthma: Prevalence and burden of disease. In: Heterogeneity in Asthma. US: Springer; 2014. p. 17-29.
Mallol J, Crane J, von Mutius E, Odhiambo J, Keil U, Stewart A, et al.
The international study of asthma and allergies in childhood (ISAAC) phase three: A global synthesis. Allergol Immunopathol (Madr) 2013;41:73-85.
Abramson MJ, Perret JL, Dharmage SC, McDonald VM, McDonald CF. Distinguishing adult-onset asthma from COPD: A review and a new approach. Int J Chron Obstruct Pulmon Dis 2014;9:945-62.
Wilson SR, Rand CS, Cabana MD, Foggs MB, Halterman JS, Olson L, et al
. Asthma outcomes: Quality of life. J Allergy Clin Immunol 2012;129:S88-123.
Tepper RS, Wise RS, Covar R, Irvin CG, Kercsmar CM, Kraft M, et al.
Asthma outcomes: Pulmonary physiology. J Allergy Clin Immunol 2012;129:S65-87.
Juniper EF. Assessing asthma quality of life: Its role in clinical practice. Breathe 2005;1:192-205.
Cui W, Zack MM, Zahran HS. Health-related quality of life and asthma among United States adolescents. J Pediatr 2015;166:358-64.
From the Global Strategy for Asthma Management and Prevention, Global Initiative for Asthma (GINA); 2015. Available from: http://www.ginasthma.org/
. [Last accessed on 2016 Sep 14].
Miller MR, Hankinson J, Brusasco V, Burgos F, Casaburi R, Coates A, et al.
Standardisation of spirometry. Eur Respir J 2005;26:319-38.
Joshi KS. Yogic Pranayama. New Delhi: Orient Paperbacks; 1982.
Gupta D, Aggarwal AN, Subalaxmi MV, Jindal SK. Assessing severity of asthma: Spirometric correlates with visual analogue scale (VAS). Indian J Chest Dis Allied Sci 2000;42:95-100.
Ohta K, Jean Bousquet P, Akiyama K, Adachi M, Ichinose M, Ebisawa M, et al.
Visual analog scale as a predictor of GINA-defined asthma control. The SACRA study in Japan. J Asthma 2013;50:514-21.
Martinez FD, Vercelli D. Asthma. Lancet 2013;382:1360-72.
Demoly P, Gueron B, Annunziata K, Adamek L, Walters RD. Update on asthma control in five European countries: Results of a 2008 survey. Eur Respir Rev 2010;19:150-7.
Barnes PJ, Jonsson B, Klim JB. The costs of asthma. Eur Respir J 1996;9:636-42.
Vedanthan PK, Kesavalu LN, Murthy KC, Duvall K, Hall MJ, Baker S, et al.
Clinical study of yoga techniques in university students with asthma: A controlled study. Allergy Asthma Proc 1998;19:3-9.
Chandra FA. Respiratory practices in yoga. In: Timmons BH, Ley R, editors. Behavioral and Psychological Approaches to Breathing Disorders. New York: Plenum Press; 1994. p. 221-32.
Cooper S, Oborne J, Newton S, Harrison V, Thompson Coon J, Lewis S, et al.
Effect of two breathing exercises (Buteyko and pranayama) in asthma: A randomised controlled trial. Thorax 2003;58:674-9.
Levy ML, Thomas M, Small I, Pearce L, Pinnock H, Stephenson P. Summary of the 2008 BTS/SIGN British Guideline on the management of asthma. Prim Care Respir J 2009;18 Suppl 1:S1-16.
Holloway EA, West RJ. Integrated breathing and relaxation training (the Papworth method) for adults with asthma in primary care: A randomised controlled trial. Thorax 2007;62:1039-42.
Mishra SK, Singh P, Bunch SJ, Zhang R. The therapeutic value of yoga in neurological disorders. Ann Indian Acad Neurol 2012;15:247-54.
] [Full text]
Nagarathna R, Nagendra HR. Yoga for bronchial asthma: A controlled study. Br Med J (Clin Res Ed) 1985;291:1077-9.
Khanam AA, Sachdeva U, Guleria R, Deepak KK. Study of pulmonary and autonomic functions of asthma patients after yoga training. Indian J Physiol Pharmacol 1996;40:318-24.
Saxena T, Saxena M. The effect of various breathing exercises (pranayama) in patients with bronchial asthma of mild to moderate severity. Int J Yoga 2009;2:22-5.
] [Full text]
Nagendra HR, Nagarathna R. An integrated approach of yoga therapy for bronchial asthma: A 3-54-month prospective study. J Asthma 1986;23:123-37.
Singh V, Wisniewski A, Britton J, Tattersfield A. Effect of yoga breathing exercises (pranayama) on airway reactivity in subjects with asthma. Lancet 1990;335:1381-3.
Manocha R, Marks GB, Kenchington P, Peters D, Salome CM. Sahaja yoga in the management of moderate to severe asthma: A randomised controlled trial. Thorax 2002;57:110-5.
Goyeche JR, Abo Y, Ikemi Y. Asthma: The yoga perspective. Part II: Yoga therapy in the treatment of asthma. J Asthma 1982;19:189-201.
Freitas DA, Holloway EA, Bruno SS, Chaves GS, Fregonezi GA, Mendonça KP, et al.
Breathing exercises for adults with asthma. Cochrane Database Syst Rev 2013;10:CD001277.
Ernst E. Breathing techniques – Adjunctive treatment modalities for asthma? A systematic review. Eur Respir J 2000;15:969-72.
British Thoracic Society, Scottish Intercollegiate Guidelines Network. British Guideline on the management of asthma. Thorax 2008;63 Suppl 4:iv1-121.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2], [Table 3]