Man Bites Downward-Facing Dog

Yoga Journal’s Medical Editor Responds to The New York Times

By Timothy McCall, MD (revised January 29, 2013)

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Could yoga make you fat (especially if you’re a woman)? Does it cause hundreds of strokes per year? Sex you up so much you’ll engage in unethical behavior? Did the entire discipline start out as a sex cult? If you read The New York Times you might think so. As much as I’ve often disagreed with him, up until now I’ve been diplomatic in my responses to William Broad’s writings about yoga in The Times and in his book The Science of Yoga. But after his recent article in which he asserted that “yoga is remarkably dangerous — for men,” I felt it was time to speak up.

For those who’ve forgotten, Broad is the science reporter who a year ago published an alarming and controversial book excerpt entitled “How Yoga Can Wreck Your Body,” in the Sunday New York Times Magazine. While I joined the chorus in the yoga world that responded to its mistakes and exaggerations, I also wrote that by raising the issue of yoga injuries — which some teachers were not discussing enough — he provided a service. My Yoga International review recommends reading his book. But a disturbing pattern of sensationalism is now emerging. Broad has repeatedly made shocking, man-bites-dog claims, which succeed in bringing attention to himself and his book, but which fail to hold up under scrutiny. No extraordinary evidence backs his extraordinary claims.

One, parroted by Maureen Dowd in her popular Times column prior to his book’s release, is that yoga could make you fat — particularly if you’re female. Broad based that assertion entirely on an extrapolation from the long-documented fact that practicing yoga can lower the metabolic rate. Why is that? When you are stressed, your sympathetic nervous system steels your body for fight or flight. Your heart beats faster, your blood pressure goes up, more blood is delivered to large muscles, all of which burns calories. Calm your mind and relax your body with yoga and your parasympathetic nervous system kicks in, and you don’t burn all those nervous-energy calories. Broad’s weight gain warning was pure speculation without an ounce of data behind it, and neglected much of the story.

Did Broad consider the effects of stress-related eating? Cortisol-induced binges, and what scientists studying rats call “food seeking behavior?” What about the stress hormone’s penchant for turning extra calories into belly fat, the most dangerous kind metabolically? And yoga’s proven ability to lower cortisol? None of it is discussed in The Science of Yoga. In fact, there’s only one brief mention in the entire book of this hormone so intimately tied to obesity (and many other diseases). He also failed to cite any of the scientific studies that have examined the issue of yoga and body weight. While that research is far from definitive, the preponderance of the evidence suggests that yoga can help people drop excess weight, and prevent unhealthy weight gain, as I pointed out in my 2007 book Yoga as Medicine (which he must have read since his book recommends it).

For example, Dr. Alan Kristal of the Fred Hutchinson Cancer Research Center in Seattle and colleagues surveyed more than 15,000 people in their fifties, 132 of whom had been regular yoga practitioners for at least four years. During the previous ten years, overweight people in the yoga group had lost an average of five pounds, compared to a 13.5 pound gain among overweight non-practitioners. A more recent study, published in The International Journal of Yoga (full text here) found that among more than 200 women, all long-term yoga practitioners over the age of 45, the more yoga they practiced, the lower the body mass index (BMI). The results held up even when adjusted for such factors as age and lifestyle. Among the 49 women who had practiced more than 25 years, there were no cases of obesity.

Then there was Broad’s Times article on yoga and sex scandals, which argued they were inevitable because yoga supercharges libido. While scientific studies have found the practice improves sexual function and satisfaction, Broad’s notion that any of this explains inappropriate sexual behavior is once again speculation without data. And, his assertion in The Science of Yoga that “the entire discipline [of yoga] itself began as a sex cult,” is false and an insult to millions of Hindus.

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In making the case that men are at higher risk of yoga injuries in the recent Times article, Broad examines 18 years of data — from 1994 to 2011 — from a federal program that monitors emergency room visits. He didn’t provide any raw numbers (making it hard to interpret the results since we don’t know if we’re talking about 12 cases or 12,000) just the relative percentages for males and females in 4 categories of “major” injuries 1) strains or sprains 2) dislocations 3) fractures, and 4) nerve damage. So, for example, men had 24 percent of the dislocations in the reports — more than expected — as Broad estimated they comprised just 16 percent of yoga practitioners (though no peer-reviewed scientific journal would accept his method for calculating that 16 percent).

In his analysis, Broad only included “major injuries,” but how he decided what to include and what to exclude seems idiosyncratic at best. Ankle sprains, for example, can be painful, but most of them shouldn’t be categorized as major injuries. (Of note, Broad categorized sprains and strains as minor in the paperback version of his book, when he analyzed the same government data.) In contrast, syncope (fainting), which Broad found disproportionately affects women, he categorized as “minor,” and thus didn’t include in his analysis. The question is whether Broad decided which categories to include after examining the data — perhaps okay in journalism but a serious no-no in scientific research, as there’s the risk of cherry-picking the data that support your theories.

Most surprisingly, Broad’s latest Times article failed to mention the lifethreatening condition that was the subject of one of his book’s most shocking claims. Using unscientific methodology, he calculated that yoga causes 300 strokes a year. That would be over 5000 cases of yoga-induced strokes in 18 years. You would think that if Broad had found support for that claim in the government’s emergency room tracking data he would have reported it.

As I wrote on the Yoga for Healthy Aging blog, I believe men, in comparison to their proportions in the yoga world, are more likely to take more strenuous and acrobatic classes where injuries would appear to be more common. And, in my experience, men are more likely to push too hard for results (although women can do this too), and this is a well-known precipitant of injury. Most yoga teachers with whom I’ve spoken believe that more flexible students (disproportionately women) are far more likely to get such injuries as hamstring muscle tears and overstretching of pelvic and spinal ligaments, serious (and often nettlesome) but probably less likely to result in a trip to the ER. These factors — and poor methodology — more than any inherently greater male susceptibility to injury, could explain Broad’s findings entirely. The bottom line that there isn’t enough evidence at this point to say which gender is at higher risk for yoga injuries. And we certainly should not, based on relative percentages in a few categories of injuries, be labeling yoga as “remarkably dangerous” for men.

“Some yoga practitioners will surely see my analysis as unconvincing,” Broad writes. “It’s the kind of topic,” he says, “that can only benefit from thorough discussion* — as well as rigorous new studies that can rule out the possibility of false clues.”

Finally something we can agree on.

Dr. Tim McCall

Board-certified internist and yogi Timothy McCall, MD teaches yoga therapy seminars worldwide. He is the medical editor of Yoga Journal and the best selling author of Yoga as Medicine. This article appeared in his email newsletter, available at DrMcCall.com, where you can download the PDF of this article, with hyperlinks.

*In conjunction with the publication of this article, Yoga U, an online educational resource, will rebroadcast free of charge a 4-hour telesummit on yoga injuries recorded last year, featuring Timothy McCall and many of the country’s leading yoga teachers.

©2013 Timothy McCall, MD