Effects of yoga on cardiovascular disease risk factors: A systematic review and meta-analysis

Background: The aim of this review was to systematically assess and meta-analyze the effects of yoga on modifiable biological cardiovascular disease risk factors in the general population and in high-risk disease groups. Methods: MEDLINE/PubMed, Scopus, the Cochrane Library, and IndMED were screened through August 2013 for randomized controlled trials (RCTs) on yoga for predefined cardiovascular risk factors in healthy participants, non-diabetic participants with high risk for cardiovascular disease, or participants with type 2 diabetes mellitus. Risk of bias was assessed using the Cochrane risk of bias tool. Results: Forty-four RCTs with a total of 3168 participants were included. Risk of bias was high or unclear for most RCTs. Relative to usual care or no intervention, yoga improved systolic (mean difference (MD)=-5.85 mm Hg; 95% confidence interval (CI) = -8.81, -2.89) and diastolic blood pressure (MD = -4.12 mm Hg; 95% CI = -6.55, -1.69), heart rate (MD = -6.59 bpm; 95% CI = -12.89, -0.28), respiratory rate (MD = -0.93 breaths/min; 95% CI = -1.70, -0.15), waist circumference (MD = -1.95 cm; 95% CI = -3.01, -0.89), waist/hip ratio (MD = -0.02; 95% CI = -0.03, -0.00), total cholesterol (MD = -13.09 mg/dl; 95% CI = -19.60, -6.59), HDL (MD = 2.94 mg/dl; 95% CI = 0.57, 5.31), VLDL (MD= -5.70 mg/dl; 95% CI = -7.36, -4.03), triglycerides (MD = -20.97 mg/dl; 95% CI = -28.61, -13.32), HbA1c (MD = -0.45%; 95% CI=-0.87,-0.02), and insulin resistance (MD=-0.19; 95% CI=-0.30,-0.08). Relative to exercise, yoga improved HDL (MD= 3.70 mg/dl; 95% CI = 1.14, 6.26). Conclusions: This meta-analysis revealed evidence for clinically important effects of yoga on most biological cardiovascular disease risk factors. Despite methodological drawbacks of the included studies, yoga can be considered as an ancillary intervention for the general population and for patients with increased risk of cardiovascular disease. (c) 2014 Elsevier Ireland Ltd. All rights reserved.