by Baxter
Over the years, as I have worked with individuals on a variety of health issues using yoga as a therapeutic tool, I have observed that those who do a regular home practice (usually two to four times a week) have more dramatic and sustained improvement in their health. There are always other factors that come into play, but in general, if they do their work regularly, they feel better and function better over time. This has been especially true for the students who have chronic pain conditions. But can what I have observed informally be applied more broadly to our general population of yoga practitioners? And what if you are generally healthy? Does yoga give you an advantage over other things? Well, a new study seems to say yes to that and a few other propositions about yoga’s benefits.
In a recent study entitled “
Frequency of Yoga Practice Predicts Health: Results of a National Survey of Yoga Practitioners,”the authors out of the University of Maryland School of Nursing and the National Institutes of Health Clinical Center looked at the positive health benefits of yoga, not simply the therapeutic benefits of yoga for those with illness and injury. Their stated purpose was to examine the relationship between yoga practice and health by evaluating such things as subjective well-being, diet, BMI, smoking, alcohol/caffeine consumption, sleep, fatigue, social support, mindfulness, and physical activity. They chose the tool of a survey, administered to practitioners of a specific style of yoga with a strict standardization of teaching that would likely contribute to consistent instruction, Iyengar Yoga, which could lead to a more valid set of results. Out of a pool of over 18,000 potential students at fifteen Iyengar schools in the US, they sent out a cross-sectional, anonymous internet survey to 4307 randomly selected students. They received back 1045 (24.3%) surveys completed and ready for analysis.
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When they evaluated their data, they found that home practice had the greatest predictive positive effect on health. Frequency of home practice favorably predicted the following: mindfulness, subjective well-being, BMI, fruit and vegetable consumption, vegetarian status, sleep, and fatigue. They also found that the different components of yoga practice also had some influence: “Each component of yoga practice (different categories of physical poses, breath work, meditation, philosophy study) predicted at least 1 health outcome.”
Finally, they concluded, “Home practice of yoga predicted health better than years of practice or class frequency. Different physical poses and yoga techniques may have unique health benefits.” This so wonderfully echoed something I probably say once a week in class: “I love that you come to yoga class once a week with me, but if you want to get the real benefits of yoga, you need to practice on your own a few times a week.” And, of course, Patanjali in the Yoga Sutra says the same thing when he states that you will achieve your goals when you practice regularly over a long period of time!
To recap what the authors were looking at, I quote their study once again:
“The objective of this study is to better understand the interrelationship between yoga practice and health. Specifically, the study addressed the contributions of yoga practice in general (years of practice, classes per month, and/or days per month of home practice) and practice of specific components of yoga practice (physical poses, breath work, meditation, and/or philosophy study) to these aspects of health. It is important to study the unique contributions of the individual components of yoga practice because some aspects of yoga practice may be more effective than others in improving specific health outcomes such as body weight, sleep, and mental health.”I couldn’t agree more! As I work with individuals, I am always considering which component practices would best serve the unique circumstances an individual is working with in designing a home practice for them.
When reading the fine print, a few notable specific observations popped out at me, specifically related to the study of yoga philosophy. Notably, frequency of philosophy study was the yoga practice variable that most often predicted health. In addition, more frequent philosophy study also contributed to a lower BMI and higher odds of being a vegetarian. And this sometimes equated to only reading philosophy once a week.
When they looked at categories of poses, “vigorous poses remained an independent predictor of BMI and sleep quality, for every additional day per week of vigorous pose practice, BMI decreased .21 of a point, and sleep disturbance improved .26 of a point.” And doing gentle poses more often correlated to a greater chance of eating vegetarian diet and drinking less alcohol. In regards to fatigue, it seemed that for older practitioners, even a small amount of yoga had a positive effect on fatigue levels and sleep disturbances.
And since so many of us are concerned about eating in a healthy way as we age, “more frequent practice of gentle poses, including supine restorative poses and relaxation pose (Savasana), were associated with three aspects of health that deal with feeding behaviors or cravings: higher fruit and vegetable consumption, higher rates of vegetarianism, and lower alcohol consumption.”
When the question of how does yoga achieve these impressive results, the authors mention a theory on how yoga decreases stress: “It has been postulated that yoga impacts the Hypothalamic-Pituitary-Adrenal (HPA) axis and the Sympathetic Nervous System (SNS) response to stress, possibly via direct vagal stimulation.” In other words, yoga may have some impact on the endocrine and autonomic nervous systems that results in lowered stress reactions in the body. We have alluded to this mechanism of action in past blog posts, and although this study does not look at the biochemistry of those surveyed, this theory still seems plausible as an underlying explanation for yoga’s benefits.
I need to go back to the philosophy findings. The authors go on to note that all those who had regular philosophy study were also practicing a lot of yoga in general. They concluded,” Thus, any relationship between philosophy study and health may reflect the relationship of frequency and intensity of yoga practice to health. This provides more evidence that an intense practice involving all aspects of yoga practice may be more beneficial to health than a less intense practice that includes only one or two aspects of yoga practice, such as just practicing the physical poses or breath work.” Darn! I can’t just sit around and read about yoga and expect good health! But we all kind of know that already from our personal experience, don’t we?
So, does yoga lead to good health? Well, this study does not actually prove this. It infers that may be the case, but it does not conclude that yoga causes good health. It may seem like semantics, but it simply means more work needs to be done to show causality between practicing yoga and good health.
Like all studies, there were some blind spots. Some of the limitations of the study included: studying only to Iyengar yoga practitioners in the USA; anonymous online surveys have the potential for lots of inaccurate data; the response rate of 27% was low; most of the subjects were predominantly white, female, and highly educated, so diversity was not represented; and this kind of study allows one to draw inferences, but do not allow one to conclude that yoga actually impacts health.
Despite these limitations, yoga still looks like a good bet to help improve your overall health. It seems you don’t necessarily need to practice for years to get benefits, but the more you incorporate it into your daily life, the more likely you are to see the predicted positives come true for you.