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

Abstract

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 nonrandomized 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.