Research paper by Paula Chu, Rinske A. Gotnik, Gloria Y. Yeh, Sue J. Goldie, MG Myriam Hunink. European Journal of Preventive Cardiology. December 2014. [Epub ahead of print] doi: 10.1177/2047487314562741
In this study, the investigators examined data from 37 peer-reviewed, randomized, controlled trials that explored the potential effects of yoga on cardiovascular health. For meta-analysis, the investigators pooled (ie, combined) data from 32 of the 37 trials. Their conclusions, which were widely reported at the end of 2014 in the mainstream press (including Forbes.com) were that yoga may be beneficial to managing and improving risk factors associated with cardiovascular disease (CVD) and metabolic syndrome.
The total number of participants in all trials was 2768 (47% men, 53% women), with a mean age of 50 years. Of these, 1287 participants were randomized to a yoga intervention and 1461 were randomized to a control group. Study duration varied, ranging from 3 weeks to 52 weeks. Data were analyzed from the participants who completed the studies: 1094 in the yoga groups and 1301 in control groups.
Their conclusions . . . were that yoga may be beneficial to managing and improving risk factors associated with cardiovascular disease (CVD) and metabolic syndrome.
The yoga interventions used in the trials varied in style (from gentle to vigorous), frequency, and duration. Control groups varied as well and included conventional medical therapy, education, diet, and exercise. For analysis, the investigators divided the control groups into two subgroups–non-exercise and exercise–to determine the effectiveness of yoga in active vs nonactive controls.
When compared with non-exercise controls, yoga subjects showed significant improvement of risk factors for all primary outcomes: body mass index (BMI), systolic blood pressure (SBP), and low- and high-density lipoprotein cholesterol (LDL-C, HDL-C). Significant improvement was also seen in the yoga subjects in most secondary outcomes–body weight, diastolic blood pressure (DBP), total cholesterol (TC), triglycerides (TG), and heart rate–but not in fasting blood glucose (FBG) or glycosylated hemoglobin (HbA1c).
“This review demonstrates the potential of yoga to have an impact on concrete, physiological outcomes that represent some of the greatest health burdens today.” -Chu et al, 2014
Furthermore, when yoga was used in addition to medication in patients with type 2 diabetes or coronary artery disease, significant improvement was found in body weight, BMI, blood pressure, lipid levels, FBG, HbA1c, and heart rate.
When yoga subjects were compared with aerobic exercise controls (including running and cycling), the investigators found no significant difference in the benefits provided by the two approaches for body weight, SBP, DBP, heart rate, BMI, LDL-C, HDL-C, TC, TG, and FBG. The authors suggested that the similar effectiveness of the two strategies may be due to comparable underlying working mechanisms, “with some possible physiological aerobic benefits occurring with yoga practice, and some stress-reducing, relaxation effect occurring with aerobic exercise.”
The investigators concluded that yoga may prove to be a cost-effective treatment and prevention strategy for CVD and metabolic syndrome. “This review demonstrates the potential of yoga to have an impact on concrete, physiological outcomes that represent some of the greatest health burdens today,” they wrote.
Summary by Louise Fecher