Yoga and Heart Health: the Newest Study

by Baxter

In the spirit of keeping up with all the new developments in the scientific study of yoga, I’d like to share some information about a new study on yoga and heart health that came out last week. Last Tuesday, the day I went live on yogauonline.com with my own lecture series on heart health, they ran a story about a new study that reviewed a bunch of previous studies looking at yoga’s impact on various factors related to heart disease. 

Since I did not have adequate time to read over the entire study that day, I finally got to it the is week and felt it was worth letting you all know what the researchers found. First off, this is one of those studies where the researchers did not do their own new research on yoga for heart health, but instead they looked back at the work of other studies and tried to put all the data together to get a better overview of what has been studied and found so far. We call these kinds of studies “meta-analysis.” The title of the study Effects of yoga on cardiovascular disease risk factors: A systematic review andmeta-analysis reflects this. The authors looked at 44 studies that fall into the category of “Randomized Controlled Trials” (RCT). This is a kind of study design that aims at limiting the amount of “bias” that the original researchers might have had, therefore, limiting the chances of the researchers stacking the deck in favor of their desired outcome—which in this case would be that yoga is helpful for addressing heart disease. We’ll come back to this in a bit.

The study appeared in the International Journal of Cardiology, and reviewed the 44 RCTs that had been done between 1989-2013 from a variety of countries around the world—almost half were from India, 8 were from the US, and an additional 9 countries represented the remaining studies. Some looked at healthy individuals, some looked at people with diabetes, a known strong risk factor for developing heart disease, and some looked at people who had other risk factors for developing heart disease, like those with high blood pressure, obesity, or high cholesterol, to name a few. Twenty of the studies mentioned the “style” of yoga that was used in the study, with 7 studies calling it “hatha” and the other 13 naming styles like Iyengar, Anusara, and 5 others.

The conclusions the authors made as they analyzed and reviewed all of the information in these 44 studies is that a regular yoga practice can help reduce many of the leading risk factors for heart disease and strokes. To quote directly: 

"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." 

The italics are mine. This seems like great news! But before we get too excited, I want to address “ancillary intervention” and “methodological drawbacks”.

Ancillary intervention can refer to treatment options that can be done in an outpatient setting, often in someone’s home. This fits in nicely with our focus here at YFHA on developing home practices for specific goals. An ancillary intervention could also imply something added onto some other primary treatment or preventive actions, presumably more mainstream ways of addressing heart disease risk factors, like taking lipid lowering medications in the setting of high cholesterol. And that may be a reasonable recommendation if we consider the multi-pronged approach that Dean Ornish’s studies used to improve those with coronary artery disease via his Lifestyle Modification Program. Recall that in that setting, they used dietary changes, daily walking program, a daily one-hour yoga/relaxation/breathwork/meditation practice and group support meetings all together to demonstrably change the course of that disease.

The more worrisome feature of the study—the methodological drawback—is that the authors readily admit that most of the studies are not up to snuff when it comes to being scientifically rigorous studies. This means that unlike most studies sponsored by institutions like the National Institutes of Health (NIH) or studies that appear in our most prestigious medical journals, the methods of these particular studies may not up to the highest standards the authors (or I) would like to see. The authors strongly express the opinion that future research must be much better designed in order for us to have more confidence in the results that are reported. To balance out their concern over the quality of the studies, they do mention that due to the “apparent” safety and effectiveness of yoga, it can still be recommended as an additional treatment intervention to other accepted ways of addressing the treatment of risk factors for heart disease. Those specifically cited beneficial effects were on blood pressure, heart rate, respiratory rate, blood cholesterol levels, abdominal obesity and insulin resistance.

So, for us, this is some mix of good news and some lingering uncertainty about the quality of past studies. I hope these sorts of big reviews will start to result in better-designed studies in the coming years. Bottom line for all of us is that a regular yoga practice could be very helpful in lowering our chances of developing heart disease and strokes over time. If you want to learn more about my recommendations on the nuts and bolts of designing your home practice for heart health, consider joining me this evening for Part 2 of Yoga for HeartHealth. 

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