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 The Science of Yoga and Controversy: The Conversation

Adapted from the Afterword to The Science of Yoga paperback edition.

When published a year ago, The Science of Yoga stirred more controversy than anything else I’ve written as a science journalist. Before it came out, Bobby Clennell, my talented illustrator and a senior Iyengar teacher with a global following, told me the book would start a conversation. The actuality was more like a riot.

The outcry began when an excerpt ran in The New York Times Magazine in January 2012 under the headline “How Yoga Can Wreck Your Body.” A furious yogi shot back: “You are a wreck.” The excerpt was illustrated with photos of the Broadway cast of “Godspell” twisted into exaggerated poses. The postures were meant to be funny. But lots of yogis took offense. As a Chicago-based columnist remarked, the article provoked “more coverage, umbrage and yuppie outrage than the wars in Afghanistan and Iraq combined.”

Yoga for many people is a sacred refuge.

It inspires feelings of trust and loyalty that few social institutions now enjoy. But after learning how yoga can result in serious injuries, I felt an obligation to help people disentangle the good aspects of the practice from the bad. After all, yoga too often is sold as completely safe—“as safe as mother’s milk,” as a prominent guru once declared.

Readers of the magazine article had no way of knowing that the book disclosed news not only about injuries but yoga’s benefits for health and healing, sex and longevity, moods and creativity.

Most had no idea that I’m a yoga enthusiast, not a basher.

Despite the uproar, the vast majority of the hundreds of e-mails and letters I received—from yoga teachers and celebrities, doctors and therapists, yoga schools and studio owners—expressed support and even gratitude. Many told of injuries. A teacher of nearly two decades wrote with elegant simplicity: “Thank you.”

Critics accused me of sensationalism. But the letters—typically from people with substantial experience—argued otherwise. The letters described damage from strokes, spinal stenosis, nerve injury, disk rupture and dead spinal tissue. “I am currently recovering from cervical fusion and will need a lifetime of physical therapy,” a former studio owner wrote. An injured teacher told of her distress in a 28-line poem.

One of the saddest and most thoughtful letters came from an elderly man who studied with Iyengar in India for 16 years. His list of personal injuries included torn ligaments, damaged vertebrae, slipped disks, deformed knees and ruptured blood vessels in his brain.

“All that you wrote,” he said, “I can confirm in my own life.”

From readers, I learned that a number of accomplished yogis had written whole books about how to avoid yoga injuries. The books received scant attention but demonstrated the depth of concern. Kevin Khalili, a doctor in Santa Barbara, Calif., wrote X-Posed, published in 2011. Jean-Paul Bouteloup, a yoga teacher in Paris, wrote Yoga Sans Dégâts (Yoga Without Damage), published in 2006. And as early as 1980, a student of B.K.S. Iyengar—one of modern yoga’s founders—published Attention, le Yoga Peut Être Dangereux Pour Vous! (Warning—Yoga Can Be Dangerous for You!), written with a doctor and issued by the Iyengar institute in Paris.

Eager to better understand the big picture, I tracked down the latest federal statistics on yoga injuries. They backed up the anecdotal reports. Federal investigators had selected roughly 100 emergency rooms whose locations and demographics mirrored the nation’s 5,300 hospitals that take emergency cases, and that network was the basis for their national portraits. The sample of emergency rooms in 2002 showed a spike in yoga injuries to 46. By 2011 (the most recent year available), the rate had climbed to 100 cases. The doubling seemed to reflect yoga’s growing popularity. The chart below gives investigator estimates for the national totals:

Source: National Electronic Injury Surveillance System of the Consumer Product Safety Commission

Over the past decade, the annual estimates add up to more than 20,000 injuries. By definition, that figure excludes yogis who sought help from clinics, family doctors, yoga therapists, urgent-care centers and other healers—or who sought no help at all. It bears exclusively on hospital emergency admissions. So the really big picture is unknown.

Yoga defenders would argue that if 20 million people in the United States have practiced yoga in the past decade, just 0.1 percent—or one person in 1,000—went to emergency rooms. They see injury rates for activities like weight lifting and golf as higher. Fair enough.

All exercise involves some degree of risk, and yoga is no different (despite many claims to the contrary).

The trouble with rate comparisons is that they focus exclusively on the quantity of injuries and ignore their quality, or severity. No study that I know of has compared the injuries of sports and yoga in terms of gravity. Perhaps they are similar. After all, most yoga injuries tend to be minor—strains and sprains. But the hospital reports demonstrate that yoga can also result in fracture, seizure, dislocation of joints, heart failure, spinal displacement, deep-vein thrombosis, vertigo, nerve injury and brain damage.

It may turn out that yoga, despite a low rate of injury, is unusually dangerous.

On Sunday, April 15, 2012, I joined in a panel discussion on the topic of injuries at a Yoga Journal conference in New York City. The magazine’s editor, Kaitlin Quistgaard, presided. It was four against one—but I knew what I was getting into and had decided that it was important to take the issue to yoga gatherings whenever possible. The main arguments were that yoga, like any other sport or activity, has risks, and that the postures are intrinsically safe but can be misapplied in ways that harm.

All that seemed fairly reasonable, even though the points were somewhat contradictory. What I found surprising was the strong defensiveness about yoga strokes—to me, the worst of the dangers, and one of the best documented. The word stroke is a medical euphemism for how the diminished flow of blood to the head results in serious brain damage. The push-back seemed aimed at denying that the problem existed at all.

Frankly, that troubled me. Yoga Journal—before Quistgaard joined the magazine—had written about yoga strokes and how the brain damage could result in crippling disability and even death, as the book noted. Was the magazine now backpedaling? Was Quistgaard feigning disbelief? Had the outcry so polarized the yoga community that its leaders felt obliged to strike an attitude of denial? Or—perhaps worst of all—was Quistgaard simply unaware of her own magazine’s reporting? In our discussion, I was especially concerned by what I considered a lack of understanding about the strength of the scientific evidence.

During the initial outcry, yogis had expressed similar doubts and I had addressed their questions in a number of media interviews. Because strokes can result in lengthy disability and even death—because the stakes are so extraordinarily high—I have gathered the most common questions below and have attempted to answer them, making what I consider a strong case for informed caution. I also quote some of the stroke victims. To me, their warnings are the most compelling of all.

You cite a 1972 letter to the editor of the “British Medical Journal”—nothing more than correspondence. You call that evidence?

A number of top journals classify their most important reports as “letters” or, in some cases, “correspondence.” The reason is that scientific journals began centuries ago with the aim of distributing the letters of scientists—and they still reflect that origin, especially British journals. In 1951, when Watson and Crick announced their discovery of DNA’s structure, they did so in a “letter” to Nature, a prestigious British journal. As for yoga strokes, the physician who wrote the 1972 letter to the British Medical Journal was one of England’s most distinguished neuroscientists, and his warning proved to be visionary.

The reports of strokes you cite are extremely small in number and incredibly old—the first in 1973. Get real! The risk is obviously exaggerated because there are no modern reports!

The excerpt in The Times Magazine amounted to a sketch of the book’s disclosures, so its readers saw relatively little evidence concerning the issue’s persistence to the present day. But there is much.

The book cited a 2009 survey of yogis. That investigation reported four strokes—four modern cases in which yogis, not the medical establishment, told of brain damage. That showed plainly that the danger was not an aberration of the past but a reality of the present. The newest evidence comes from the federal monitoring. The injury report of 2011 tells of a man who was attending a yoga class when he suffered a stroke. He was rushed from the emergency room into the hospital proper.

I am appalled at your omission of comparative studies. All kinds of activities result in strokes. Why not compare the risks?

I too am appalled. Yoga is a huge enterprise and I wish the medical community devoted more time and energy to its study. Unfortunately, no scientist has published data on how often yogis suffer strokes and compared the rate with other sources of brain damage. I think it’s fair to assume that the risks are low—but how low is an open question.

So where are the bodies? You claim that strokes kill. But yoga authorities say they know of no deaths from yoga injuries—none, ever—for any reason at all, much less strokes. Why are you so alarmist?

I wish the facts were otherwise. But the public record shows that many yogis in apparent good health die suddenly—at times during hard training. Jeff Goodman, 58, died on the third day of an advanced teacher training course in Houston in April 2012. Jules Paxton, 45, died in New York City in 2011. Eric Berliner, 58, died in Chicago in 2010 during a master class. In Los Angeles in 2004, Sita White, 43, a British heiress and a favorite of gossip columnists, collapsed and died in a yoga class. The question is why.

Medical authorities in some cases cite natural causes. Does that rule out yoga? Jeff Goodman, the Houston yogi, was said to have died of a brain aneurysm—the thinning and ballooning of an arterial wall. Burst aneurysms have been linked to exercises like push-ups and weight lifting, which produce spikes in blood pressure as the breath is held and the abdominal muscles are contracted. Yogis do that all the time. It happens in poses that lift substantial body weight and in exercises that bottle up the breath.

Yogis can and do rupture blood vessels in their brains, though the incidents are poorly known. The emergency room reports tell of a woman who was taking a yoga class when she suddenly felt a “ripping sensation” in her brain and passed out. She was admitted to a hospital and diagnosed as having suffered an intracranial hemorrhage. So too, the man who studied with Iyengar told me of blacking out for an hour after a vigorous session and having a physician identify the underlying problem as a cerebral hemorrhage. In both cases, the brain ruptures never got written up in the scientific literature and never received notice in the public communications of medicine, as best I can tell. Instead, these two cases were known intimately to only a few people and represent the typical situation for the countless diagnoses that working doctors make every day.

Yoga authorities are right in saying that known injuries have resulted in no reported deaths. But that speaks to the limits of data collection and reporting in biomedicine rather than a demonstrable absence of fatalities among millions of yoga practitioners.

It represents a state of ignorance rather than one of knowledge.

Even if the understandings of basic science would seem to indicate a credible link between yoga and a particular fatality, a practical impediment would probably get in the way. Crime shows tend to portray forensics as a glamorous field. But a recent study by the National Academy of Sciences reveals the discipline of postmortem inquiry to be crippled by old rules, obsolete equipment, scarce funding, and inadequate staffing. Remarkably, the study told of how one jurisdiction recently conferred the title of coroner on a high school senior. The report called autopsies—which cost about $2,000—“largely budget driven.” That means that government cutbacks are turning some classes of death investigation into unaffordable luxuries.

The institutional failings and the knowledge gaps make determining the underlying cause of death especially difficult in the case of stroke. The most common type begins when the blood supply to the brain fails. The challenge is pinpointing the blockage.

The investigation requires good imaging equipment and a thorough study of the welter of arteries that loop through the head, neck and upper chest. The early doctors conducted just that kind of study in their original linking of yoga and brain damage. But the challenge can be so great that—for a large number of strokes—physicians cannot find where the obstruction of the blood supply began. The medical term for such brain damage is cryptogenic, meaning its origin remains a mystery.

Fatal strokes present an added barrier to understanding because doctors obviously cannot ask the deceased about any activity that may have been the underlying cause of death—be it yoga or something else. In contrast to this uncertainty, identifying the source of a cerebral hemorrhage can be as easy for a doctor as peering into a skull and seeing a ruptured blood vessel, perhaps a burst aneurysm.

Given the difficulties, the issue of how many people die from yoga strokes quickly becomes an exercise in estimation.

Yoga Journal—in the article that predated Quistgaard’s arrival at the magazine—examined the main kind of stroke associated with yoga and cited a medical report that put the number of fatalities at something less than one person in twenty. That figure can lead to extrapolations of the overall death rate. But that’s statistical, not observational. In the years ahead, it seems likely that the medical community will become more attuned to the threat and do a better job at uncovering its true incidence.

Why does this issue upset you so? It seems that you have become even more agitated since the book’s publication.

It’s the letters—letters from yogis who have written to me about their strokes and their upended lives. I feel entrusted with information that I am under a moral obligation to share. During public talks, I often read the letters aloud. They have prompted me to do what I can to alert yogis to what is probably an extremely low risk but one that can have extremely high consequences—if not in sending practitioners to the grave, then in crippling them and diminishing their lives.

Here are two excerpts, both quoted with permission of the authors.

The first is from a yoga beginner, a man. At 2:30 in the morning, a few hours after a yoga session, he suddenly found himself reeling physically as the part of his brain that regulates fine muscular activity, the cerebellum, began to malfunction.

“This left me on the bathroom floor thrashing around in a pool of my own vomit crying for help,” he wrote. “I was fortunately rushed to the hospital. The end result was lots of physical therapy to learn to balance and walk again, double vision, and some loss of hearing in my left ear. Prior to this, I had gone to a few yoga classes but never once was I aware that practicing yoga could cause serious injuries. Although I feel that I have made a good recovery, this incident has ruined my life both physically and emotionally. Thank you for making everyone aware of the dangers.”

The second letter is also from a man, a practitioner with more experience.

His doctors linked his stroke to the Plow.

“I remember thinking as I was doing the exercise that it felt like an unhealthy amount of pressure on my neck,” he wrote. “After the yoga series, I had a crushing headache, which was a rarity for me. The next morning, I noticed my left eyelid was drooping. At first, I thought it was possibly due to a sinus infection, because I had a cold at the time. But later I noticed that my left pupil was constricted. It took weeks of trips to different doctors before I was diagnosed.” His doctors told him that the odds of surviving such an event were one in ten thousand. The man had surgery to correct his drooping eyelid as well as four years of drugs, therapy, and brain scans. “It’s good,” he wrote, “that your article presents a warning.”

Such letters keep me doing what I can to explore the science and alert the yoga community to the known risks—to encourage the process of yoga healing itself.

I keep seeing the letters, keep thinking about the man’s odds of survival being put at one in ten thousand. That’s infinitesimal. The federal government cites the same number as the likelihood that an individual will, over a lifetime, get hit by a bolt of lightening.

Yoga is too great an enterprise to harbor inadvertent failings. My hope is that publication of the stroke narratives will—like the book and the outcry—help stimulate discussion of ways to better limit the risks and multiply the rewards.

Anything less would dishonor the constructive spirit of yoga and neglect what seems like a genuine opportunity to do some good.

I’m enormously proud of my role in this healing process and for confronting what turns out to have been a topic of lengthy and secretive deliberation—proud even when the controversy has turned personally abusive. I sleep well knowing that the book has, in all likelihood, helped people avoid serious disabilities and perhaps even death.

For all the bad news, I still see the rewards of yoga as outweighing the risks.

A century and a half of science shows the benefits to be many and the serious dangers to be few and comparatively rare. I know this happy state of affairs from practicing yoga since 1970 and from researching the book for five years.

The proviso is that yoga has to be done intelligently.

My own goal is to help promote smarter yoga, better yoga, safer yoga.

I dropped the Plow and the Shoulder Stand when I learned that doctors had linked these poses to arterial injuries and brain damage.

The continuing debate over The Science of Yoga has sparked wide discussion of how to improve safety. Over and over, I’ve heard of classes discussing the pros and the cons of different styles and poses. “How NOT to Wreck Your Body,” read the ad for a Boston class. “We will examine the ‘most dangerous’ yoga postures and offer safe methods of practice.”

Many people have told me of old routines updated, of new precautions taken, of fresh emphasis on fitting the pose to the person (and the person’s gender) rather than twisting bodies into idealized postures. A number of yoga schools now use my book in teacher training.

My expectation is that the next round of federal statistics on yoga-related injuries will show noteworthy declines.

“Thank you for opening up a door,” a longtime studio owner wrote me. The frank atmosphere resulting from the book and the discussion, she added, promise to usher in a period of “improved safety for students—and a positive yoga experience.”

William J. Broad has practiced yoga since 1970. A bestselling author and senior writer at The New York Times, he has won every major award in print and television as a science journalist. With colleagues from The New York Times, he has twice won the Pulitzer Prize, as well as an Emmy and a duPoint. He is the author or coauthor of eight books, which have been translated into dozens of languages. His journalism has twice been featured in The Best American Science Writing. He earned a master’s degree in the history of science from the University of Wisconsin. The father of three adult children, he lives with his wife in the New York metropolitan area, where he enjoys doing Sun Salutations.

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Ed: Lynn Hasselberger
Asst. Editor: Edith Lazenby