Effect of Yoga on Endothelial Function: A Systematic Review and Meta-Analysis

Introduction: Endothelial dysfunction is the initial step in the pathogenesis of atherosclerosis; and it plays a central role in the development of cardiovascular diseases and many types of human diseases (diabetes, kidney failure, cancer, and viral infections). Strategies that are effective in protecting vascular endothelial function and retard or reversing endothelial dysfunction in the early stage appear to be potential in the prevention of vascular, cardiac, and many human diseases. Several studies have been carried out on the effects of yoga on endothelial function, but the results of these studies have not been synthesized. This study aimed at conducting a systematic review and meta-analysis to determine the effectiveness of yoga on endothelial function. Methods: A systematic review and meta-analysis of studies that assessed the effect of yoga practice on vascular endothelial function was done as per the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed, Scopus, Google Scholar, and Cochrane controlled register of trials (CENTRAL) were searched from inception to August 2022. The search strategy was constructed around yoga-based techniques and endothelial function. All the yoga-based interventional studies on endothelial function or dysfunction were included in this review. A narrative synthesis and descriptive analysis were done due to the diverse methodology of selected studies. We carried out a formal meta-analysis of controlled trials that assessed the effect of yoga on flow-mediated dilatation (FMD), a measure of endothelial function. Results: A total of 18 studies were included for review involving 1043 participants. Yoga training showed improved endothelial function in 12 studies, whereas 6 studies did not find any statistically robust effect. Meta-analysis (n = 395 participants, 6-studies, 7 comparisons) showed an increase in brachial FMD by yoga practice (mean difference = -1.23%; 95% confidence interval -2.23 to -0.23; p = 0.02). The heterogeneity between the studies was 43% (Tau2 = 0.70, χ2 = 10.49). The risk of bias was low to moderate in these studies. No adverse effects were reported. Conclusions: Yoga practice improved endothelial function. Yoga could be a safe and potential integrative medicine to improve endothelial function. However, as the statistical heterogeneity, that is, variation in the FMD among the studies was moderate, large clinical trials are necessary for its clinical recommendations.

A systematic review and meta-analysis of effect of yoga and meditation on endothelial system

Background/Introduction

Endothelial dysfunction plays an important role in the pathophysiology of cardiovascular diseases and diabetes. Studies reported either an improvement in endothelial function by yoga and meditation or no significant effect. A systematic review and meta-analysis of effect of yoga on endothelial function is not available.

Purpose

The aim of this systematic review and meta-analysis is to determine the effectiveness of yoga and meditation on endothelial function in healthy subjects or patients of any age or gender.

Methods

Authors performed a systematic search for relevant research studies as per the PRISMA guidelines. The Pubmed, Scopus, Google Scholar and Cochrane controlled register of trials (CENTRAL) were screened from inception to November 2020. The search strategy was constructed around yoga based techniques, meditation and endothelial function. All the yoga-based interventional studies on endothelial function: controlled, uncontrolled, randomized, non-randomized and cross-over were included for this review. A narrative synthesis and descriptive analysis was done due to diverse methodology of all selected studies. We carried out a formal meta-analysis of controlled trials that assessed flow-mediated dilatation (FMD) which is a gold-standard measure of endothelial function.The quality of the studies was assessed using Cochrane risk of bias (RoB) tool.

Results

A total of 18 studies were included for review involving 1024 participants. Of these, 10 were RCT, one randomized cross-over study, 4 non-randomized studies and three single-group (before-after) studies. The total duration of yoga intervention ranged from 10 days to 52 weeks. Among the 18 selected studies, yoga training showed a significant favorable change in the measures of endothelial function in 12 studies (involving either healthy individuals or patients with coronary heart disease, myocardial infarction, metabolic syndrome, hypertension, migraine and dysmenorrhea) while 6 studies did not find any significant effect. Among the 15 controlled trials, 7 assessed FMD while the remaining evaluated different biomarkers of endothelial function such as circulating endothelial microparticles, asymmetric dimethyl arginine, nitric oxide or endothelin-1. Hence the results of 7 controlled trials assessing FMD were included for meta-analysis (n=384 participants) which showed a significant increase in brachial FMD by yoga practice (Mean difference = −2.02%, 95% CI: −3.72, −0.32, p=0.02). The heterogeneity between the studies was 76% (τ2=3.31, χ2=25.28) (Fig. 1).

Conclusions

Yoga and meditation can significantly improve endothelial function in healthy individuals and patients with cardiovascular disease or risk factors. Yoga and meditation can be applied clinically as a lifestyle modality for endothelial protection and cardiovascular prevention and rehabilitation.

Funding Acknowledgement

Type of funding sources: None.