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The benefits of a yoga regime on lung function in Indian Cardiovascular Artery Disease (CAD) patients

This wiki fact sheet is a critical appraisal examining the benefits of a yoga regime and it’s effectiveness of improving lung function in coronary artery disease (CAD) patients in India. This analysis is written as a component of the unit, Health Disease and Exercise at the University of Canberra (UC).

Paper in review: Asha Yadav, Savita Singh, KP Singh, Preeti Pai:  effect of yoga regimen on lung functions including diffusion capacity in coronary artery disease patients:  A randomized controlled study (2015), 8 (1):  62-67.

What is the background to this research?
CAD is a buildup of plaque in the walls of the coronary arteries, it can lead to limited or blocked blood flow to the heart and can result in chest pain or heart damage.

Prevalence in India
 * Ischaemic heart disease is the leading cause of death in India statistics reported(1.2 million deaths) 12.4% in 2004 with an increase to 23.3% in 2015. It is projected that in 2020 deaths from Ischaemic heart disease will be around 2.5 million.

The purpose of this research was to investigate if a yoga regime combining yogic exercise and pranayama breathing sequences could act as complimentary therapy to conventional medical treatment, improving lung function and efficiency in gas exchange at the alveoli-capillary membrane.

The heart and lungs work as a coupled unit. Underlying cardiac disease can have an effect on the cardiopulmonary interaction contributing to changes in lung function, which would likely have an effect on diffusion capacity at the alveolar-capillary membrane.

Current evidence in yogic interventions have demonstrated positive health responses in CAD patients showing:
 * reduction in stenosis of the coronary artery
 * suppression of sympathetic activity therefore reducing stress and anxiety
 * Improvement in anthropometry
 * improvement in cardiac measurements

Where is the research from?
The research was conducted by the Department of Physiology at the University College of Medical Sciences (UCMS) in Dehli, India. This study was published in the International Journal of Yoga. Published by Medknow and included on Pubmed central, a reputable source for peer reviewed literature in health and sciences.

What kind of research is this?
The study is a prospective randomized parallel controlled study (RCT), consisting of an intervention group (Group 1 - 3 month yoga regime and lifestyle management program) and a control group (Group II - conventional medical treatment continuance). An RCT, sound in design and methodology, evaluating if a cause and effect relationship exists can provide compelling evidence in patient improvement and is therefore an important evaluation tool in this comparative study.

What did the research involve?
This study recruited 80 outpatients with stable CAD from Teg Bhadur Hospital, Dehli, not gender specific. The subjects were assigned via a computer generated randomisation program into one of two groups, 40 subjects allocated to each group: Group I and Group II.

A screening process determined the subject selection on the basis that they met the inclusion criteria:

Each subject was required to complete a baseline physical and clinical assessment, including:
 * Angiographically proven CAD
 * Stable CAD for the last 2-6 years
 * Middle socioeconomic class
 * Pulmonary Function testing (PFTs) measurements: slow vital capacity (SVC), Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 sec (FEV1), FEV1/FVC ratio and single breath diffusion factor of the lung for carbon monoxide (DLCO)
 * Bloop pressure (BP) and Heart Rate measures

3 month Yoga intervention group (Group 1)
 * PFT Testing was undertaken at baseline = day 0, day 22 and  Post = day 90.
 * Yoga was taught 60 mins/day for 6 days in week 1.
 * Self management was an expectation of the subject for the remaining 10 weeks
 * Compliance to the program required telephone follow ups and a once weekly lab visit
 * Lectures conducted informed the subjects on lifestyle change, diet modification, stress and anxiety management.

Yoga regime program outline

Control (Group II)
 * PFT testing was undertaken at baseline = day 0, day 22 and Post=day 90.
 * Continuance of usual medical treatment
 * control subjects undertook the yoga regime post intervention

Results
Comparison in PFT results post intervention


 * A 21% improvement was reported from (Group I) in FEV1 across the course of the intervention but the variance within the group was not significant.
 * A significant improvement was established between the groups in FEV1 with the intervention group showing a 38% gain in comparison to Group II
 * DLCO reported a significant 27% improvement in Group I, demonstrating improved pulmonary function in diffusion of oxygen at the alveoli-capillary level.
 * FVC showed an improvement in group I: 1.6 (L) at baseline to 2.1(L) on day 90, a significant 31% gain. FVC within the control group had a slight reduction: 1.59 (L) at baseline to 1.57(L) on day 90.

Comparisons in cardiovascular improvement shown within respective groups post (day 90) intervention

Limitations
This study was not gender specific therefore no inferences were able to be concluded in regards to gender related factors. The study relied on self management for the yoga intervention, there is no reporting on the compliance of the subjects which could have an affect on the study's validity.

Conclusions
This current intervention provides significant evidence that a yoga intervention in CAD patients in conjunction with continuation of conventional medicine improves cardiopulmonary function. The effects of yoga on the cardiopulmonary system are: a decrease in sympathetic reactivity promoting the withdrawal of the broncho-constrictor mechanism. An improvement in lung capacity and compliance enhances the efficiency in gas exchange at the alveolar.

Practical advice
It is important to understand that the authors have proposed that this yoga intervention be in addition to the continuation of conventional medicine. The techniques in Pranayama have been taught to the subjects in this study, therefore it would be advised that correct instruction was sought to perform Pranayama and medical clearance obtained by physician.