By Concepta Merry, MB, BCh, BAO, BA
Associate Professor, Global Health, School of Medicine, Trinity College Dublin; Integrative Medicine Fellow, University of Arizona, Tucson
Dr. Merry reports no financial relationships relevant to this field of study.
SYNOPSIS: Although the data on yoga in asthma are only of moderate quality, they do suggest that yoga may improve quality of life and asthma symptoms.
SOURCE: Yang ZY, Zhong HB, Mao C, et al. Yoga for asthma. Cochrane Database System Rev 2016;4:CD010346. DOI: 10.1002/14651858.CD010346.pub2.
- This review of 15 clinical trials on yoga for people with asthma found improved quality of life, improved asthma symptoms, and less medication use.
- The authors recommended larger, high-quality clinical trials to comment definitively on the effectiveness of yoga for asthma, including trials that include a sham yoga group for comparison purposes.
Three hundred million people worldwide suffer from asthma, and unfortunately this number continues to rise.1 Pathophysiologically, asthma is a disease of the airways, but in reality the effects of asthma extend far beyond the lungs and negatively affect quality of life.2
It is biologically plausible that the ancient Indian practice of yoga could offer some relief for the physical and psychological effects of asthma. It is oversimplistic to refer to yoga as a single entity, given that there are more than 40 different types of yoga. However, common to the many different types of yoga are breathing exercises (pranayama), postures (asanas), and meditation (dhyana), which theoretically could help asthmatics by:
- reducing airway hyper-responsiveness,
- triggering the relaxation response, and/or
- increasing lung capacity.3,4
A group of Chinese researchers recently published a Cochrane review of yoga in asthma. Initially, they looked at any study of yoga in asthma, including studies comparing the effects of yoga vs. usual care (or no intervention) or yoga vs. sham intervention. Following detailed review of the available studies, they selected 15 studies, which included a total of 1,048 participants, for review. Most of the studies involved adults only, but two studies included children and adolescents. Understandably, given the origin of yoga in India, most of these studies came from India.
They found some evidence that yoga may improve quality of life in people with asthma (mean difference in Asthma Quality of Life Questionnaire [AQLQ] score per item 0.57 units on a 7-point scale; 95% confidence interval [CI], 0.37-0.77), improve symptoms (standardized mean difference 0.37; 95% CI, 0.09-0.65), and reduce medication use (risk ratio 5.35; 95% CI, 1.29-22.11) in people with asthma.
The mean difference for the AQLQ score exceeded the minimal clinically important difference of 0.5 as per other medical interventions, but this needs to be interpreted with care as the two key studies that included a placebo found no difference. There was no statistically significant impact of yoga on the forced expiratory volume in one second (FEV1) (mean difference 0.04 L; 95% CI, -0.10 to 0.19). There were no serious adverse events associated with yoga across the studies; however, this was based on a very limited number of data points.
Overall, the authors concluded that there is moderate-quality evidence that yoga may improve quality of life and symptoms in people with asthma. However, they effectively added a disclaimer saying that these findings are preliminary and suggestive rather than conclusive. The authors recommended that large, well-conducted, randomized, controlled trials are needed to fully assess the effect of yoga in asthma. Specifically, the authors recommend the inclusion of a sham yoga intervention group. Ethically designed sub-studies looking at special populations, such as children and people with severe asthma, also need to be considered if possible.
It is always disappointing when a Cochrane review fails to answer the question at hand because of insufficient quality data. Sometimes the main contribution a Cochrane review of an integrative therapy makes is to offer a blueprint for design of future studies needed to fill the existing gaps, just as we have seen in this review. It is interesting to ponder how often funders and principal investigators take these recommendations into consideration when designing new studies.
- Masoli M, Fabian D, Holt S, Beasley R; Global Initiative for Asthma (GINA) Program. The global burden of asthma: Executive summary of the GINA Dissemination Committee report. Allergy 2004;59:469-478.
- Adams RJ, Wilson DH, Taylor AW, et al. Psychological factors and asthma quality of life: A population based study. Thorax 2004;59:930-935.
- Vempati R, Bijlani RL, Deepak KK. The efficacy of a comprehensive lifestyle modification programme based on yoga in the management of bronchial asthma: A randomized controlled trial. BMC Pulm Med 2009;9:37. doi: 10.1186/1471-2466-9-37.
- 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.