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I get a lot of questions about the benefits of yoga, and they’re very difficult to answer for a number of reasons. One is that yoga is so diverse — different types of yoga (and different teachers and different classes) offer very different stimuli. Even within a given type of yoga, it’s a very “mixed” activity, working on flexibility, strength, as well as possibly cardio and mental state. Given these challenges, it’s not surprising that there’s a lack of solid research into the benefits of yoga, so I’m always happy to see a study that looks at something more quantifiable than “sense of wellness.”
With that preamble, here’s a press release about a new Ohio State study, which found that women who practiced yoga had lower amounts of a cell called interleukin-6 (IL-6) in their blood. IL-6 is a cytokine (a type of cell produced by the immune system) associated with inflammation, which has been implicated in heart disease, stroke, diabetes and other diseases. Great!
If you look more carefully at the study, though, it’s not quite the smoking gun we’re looking for. For one thing, it wasn’t a “prospective” study that observed changes over time. Instead, they took one group of yoga experts, and compared them to another group of yoga novices. The experts had lower levels of IL-6, but of course it’s hard to know whether the personality (or physical) traits that had led these people to become yoga masters also had other effects that put their bodies under lower stress. The study also looked at how the subjects’ IL-6 levels responded to stressful tests like cold-water immersion and hard math problems. Again, the yoga experts did better, but that doesn’t really tell us anything definitive.
Surprisingly, one test that showed no difference between the novices and the experts was in their physiological response to a yoga session. Here’s what Lisa Christian, one of the researchers, had to say about that:
“Part of the problem with sorting out exactly what makes yoga effective in reducing stress is that if you try to break it down into its components, like the movements or the breathing, it’s hard to say what particular thing is causing the effect,” said Christian, herself a yoga instructor. “That research simply hasn’t been done yet.”
Which is basically what I was saying at the top of this post. Yoga is complicated — and for now, the research looking for its “secret” remains pretty sketchy.