Researchers discredit yoga as medicine



Fifteen years ago, a handful of poorly constructed, clearly biased studies purported to show that prayer was a legitimate medical tool. Americans fell for it, and we still haven't learned our lesson.

Adrian Hummell, a Bikram Yoga instructor from Bethesda, Maryland, is photographed demonstrating a pose on October  10, 2013.




Studies come out on a near weekly basis trumpeting the benefits of yoga for any problem. The quasi-miraculous healing powers of yoga are, I concede, more credible than the truly miraculous healing power of a divine being. At least there is a nexus between health and yoga -- the human body -- which is something you can't say for therapeutic prayer.

The yoga studies, however, contain myriad methodological problems, some similar to those that plagued prayer research.

First, what is yoga? That's not a zen koan, but an honest question. In a real, practical sense, medical researchers have to agree on the elements essential to yoga practice before they can test it as a therapy. Is deep breathing or stretching the source of therapeutic benefit? Or maybe it's simple exercise, which wouldn't exactly be news.

When you test a pill for heart disease, you give some people the pill and others a placebo (or an existing medication). Unless they're extremely motivated and expert in chromatography, the patients can't tell which group they're in. It's not easy to convince someone that they've been doing yoga for six weeks when they haven't, so the placebo effect is always a problem.

A systematic review on the treatment of asthma with yoga was published in 2011. The author found that the methodology of the underlying studies was "mostly poor." High dropout rates also biased the results. In the only study that offered a credible placebo control -- a nonyogic stretching regimen -- yoga offered no benefit.

A review of yoga for the treatment of schizophrenia, published in 2013, concluded that "no recommendation can be made regarding yoga as a routine intervention for schizophrenia patients." A 2013 review paper on yoga for hypertension found that "a definite conclusion about the efficacy and safety of yoga cannot be drawn."

Why haven't you already heard about all of these anti-yoga studies? They have no constituency, and therefore don't interest the media much.

When a journal article showing that yoga improves quality of life in breast cancer patients came out earlier this month, hundreds of stories trumpeted the results in the mainstream media. Yet it's difficult to find any mention of the review articles discussed above.

There aren't many people today who will click on stories about how yoga won't solve their health problems. So the negative studies never make it beyond medical journals.

By all means, do yoga, pray and eat lemons, if those things bring you contentment. Do yoga especially if it's your preferred form of exercise; exercise is a health intervention supported by thousands of clinical trials.

But recognize the "yoga as medicine" craze for what it is: an indicator of the zeitgeist, not a scientific discovery.

Last modified: March 24, 2014