 This is the first video in a six-part series on yoga. In this series, I'll look at the effect yoga may or may not have on a wide variety of conditions, and yes, do a little myth-busting, but in both directions. Check it out. The practice of yoga for health has become popular in the United States and worldwide. A 2016 survey estimated that 36 million Americans may be involved in yoga to varying degrees. Though the origins of yoga go back thousands of years, it was only introduced in the United States about a century ago. What are the risks and the benefits? Yoga users tend to report having a better health status, but that doesn't necessarily mean yoga was the cause. For example, yoga practitioners were more likely to be normal weight, rather than obese, and that alone could give you better health. Of course, if the yoga was responsible for the weight loss, then that would certainly be to yoga's credit, but yoga users are also more likely to be white, female, young, and college-educated, all of which are independently associated with better health status, the same thing with higher socioeconomic status. Yoga practitioners also tend to exhibit other positive health behaviors, specifically more regular physical activity in general, and a vegetarian diet, and the more yoga people practice, the more likely they were to cut out meat and eat more and more fruits and vegetables. For every additional day per week of yoga practice, the odds of being vegetarian increased 20%. About one in three yoga teachers surveyed in the UK follow a plant-based diet much higher than the general population. So, when you're doing a study like this, comparing the cardiovascular health of yoga practitioners to runners to sedentary individuals, you can see how difficult it would be to tease out the effects of yoga when significantly more yogis reported refraining from eating meat compared to the other two groups. It's like when I was reading about the role of yoga in the prevention and management of various cardiovascular diseases. I was so excited to read that yoga could significantly reduce cholesterol levels. After all, heart disease is the number one killer of men and women, and when I looked at those studies, I got really excited. Reversal of coronary atherosclerosis with yoga? I thought the only lifestyle intervention that could reliably do that was a whole food plant-based diet. Well, what do you think the yoga lifestyle intervention was? A diet pack so full of whole plant foods, fruits, vegetables, whole grains, beans, and nuts, they were getting about 50 grams of fiber a day. No wonder they got heart disease reversal. But what role, if any, did the yoga itself actually play? Now, if yoga gets you to adopt a better lifestyle, stop smoking, eat healthier, great! Whatever gets people to take better care of themselves, right? If your tinfoil hat tells you Martians want you to skip the donuts, I'm all in favor. Whatever it takes. But if we are to tease out whether practicing yoga has any special benefits in and of itself, we really need to look at interventional studies, or randomized controlled trials that go beyond just associations and correlations and can instead prove cause and effect. For example, when we find yoga users have better health status and are less likely to be obese, that could be reverse causation, meaning instead of yoga leading to better health and a normal weight, maybe being in better health, not being obese, is leading to more yoga. Same with the flip side. When you read that yoga practitioners are more likely to have mental health conditions, depression, anxiety, musculoskeletal conditions like arthritis, gout, lupus, fibromyalgia, joint pain, sprains, and asthma, yeah, maybe yoga could be contributing to some of those conditions, like muscle sprains, but for most of these, it's probably reverse causation, right? People with diseases seeking help. Are they getting it? The only way to know for sure is to put it to the test, which we'll explore next.