The metabolic dips also raised an issue that bore on personal appearance rather than moods but was too central for the scientists to ignore. Chaya’s team noted that physiological slowing of yoga in theory “creates a propensity for weight gain and fat deposition.” In other words, individuals who took up the discipline would reduce their basal metabolic rate to such an extent that they required less food and fewer calories—or would add pounds if they ate and exercised in the customary manner.
This novel finding of physiology might have won attention, but it clashed with the happy talk of popular yoga. Teachers, the Internet, and how-to books had long echoed with confident declarations that yoga speeds up the metabolism and results in an almost magical loss of weight. It was one of modern yoga’s credos— equal in some respects to the illusory surge of oxygen to the body and brain. In truth, the metabolic conviction was so deeply held that no inconspicuous finding in faraway India stood a chance of undoing the fashionable myth.
Tara Stiles exemplified the durability. The attractive model turned yoga teacher favored short shorts and tank tops, and managed to keep herself beanpole thin. In Manhattan, she ran Strala Yoga in NoHo, a chic neighborhood north of Houston Street. In 2010, she came out with Slim Calm Sexy Yoga, its cover emblazoned with a photograph of Stiles in an eye-catching pose. The book featured an endorsement from Jane Fonda and rose fast to become the number-one yoga seller on Amazon. Early in 2011, The New York Times profiled Stiles, saying the twenty-nine-year-old displayed not only sexy good looks but down-to-earth charm.
The title of her book led with Slim, and Stiles worked hard in the text to deliver on the promise. She devoted a chapter to slenderizing and explained what seemed to be the scientific basis for why the discipline worked so well at keeping off the pounds. Yoga, she declared, will “rev up your metabolism.” Getting specific, she recommended a series of postures meant to throw the body into high gear in the service of shedding weight. “Even if you think you have a sluggish metabolism,” Stiles said, “practicing this routine twice a week will keep it humming—and help you burn calories all day.” She emphasized the point in large type spread across the top of the page, advertising her custom routine as “Metabolism Revving.”
The bold declarations of Stiles not only contradicted the body slowdowns that the Bangalore team had documented. They also clashed with the particulars that Mel Robin had told our class. For instance, Stiles listed the Shoulder Stand as one of her metabolism lifters. In contrast, Robin had described the inversion as “one of the most relaxing postures in yoga.” And Gune, of course, had recommended the pose to Gandhi for its calming action.
Chaya, the physiologist in Bangalore who had practiced yoga since childhood, told me that the secret of weight loss had nothing to do with a fast metabolism and everything to do with the psychological repercussions of undoing stress. “Yoga affects the mind—and desire,” she said. “So you eat less.”
If yoga can foster serenity and lift moods, what are its repercussions for depression, where the requirements for emotional uplift are much greater? It was a tough question. Amy Weintraub in her book, Yoga for Depression, recounted her own experiences and prescribed many practical ways of dealing with the blues. But depression has many faces and, in its most severe forms, is crippling.
Everyday gloom involves low feelings and loss of pleasure, perhaps due to minor setbacks. That kind of dejection, by nature, is fleeting. By contrast, the symptoms of clinical depression last two weeks or more. A seriously depressed person can feel anything from hopelessness and discouragement to worthlessness and despair. The World Health Organization says that, every year, nearly one million despairing people take their own lives. That is more than the number of people killed annually in crimes or war. In industrialized societies, despite floods of antidepressants, rates of suicide and depression are going up, not down.
Once again, scientists in Boston zeroed in on the question. Their studies went far beyond clinical trials and patient evaluations to examine neurochemistry. The team represented the elite of the Boston medical world—the Boston University School of Medicine and the Harvard Medical School and its McLean psychiatric hospital. The hospital is famous for its neuroscience research as well as its extensive roster of celebrity patients, including the mathematician John Nash, the poet Sylvia Plath, and the musician James Taylor.
Chris C. Streeter, the head of the team, held faculty appointments in psychiatry and neurology at the Boston University School of Medicine and lectured in psychiatry at the Harvard Medical School. Plus, she knew yoga and knew people who knew yoga. Her team focused on an important chemical in the human brain that goes by the tongue-twisting name of gamma-aminobutyric acid—or, easier to say, GABA. It is a major neurotransmitter and regulator of the human nervous system. Many reports have linked depression to low GABA levels. So a smart question was whether yoga went about easing depression by raising concentrations of the neurotransmitter.
Scientists have known about GABA since the 1950s. But it took a long time to understand its role in the brain and to develop the scientific tools to easily track its comings and goings. GABA works by blocking actions rather than causing them. It is known as an antagonist. Such chemicals, when they bind to cellular receptor sites in the nervous system, disrupt interactions and inhibit the functions of other neurotransmitters. In general, GABA slows the firing of neurons, making them less excitable. So high levels of the neurotransmitter have a calming effect. When alcohol and drugs like Valium bind to GABA receptor sites, they increase the molecule’s efficiency and thus promote its actions as a sedative and a muscle relaxant. GABA itself tends to promote relaxation and reduce anxiety.
By the 2000s, brain imaging had advanced to the point that tracking GABA could be done fairly inexpensively. Scientists judged the time right to address the yoga question.
The team found lots of potential subjects. Boston, starting with Thoreau and James, had evolved into a yoga hotspot. In modern times, it pulsed with many thousands of practitioners.
The team selected eight who practiced a number of diverse styles. They were Ashtanga (the gymnastic style developed by Pattabhi Jois, a student of Krishnamacharya’s), Bikram (the hot yoga of Choudhury), Hatha (the ancient classic), Iyengar (the modern classic), Kripalu (developed by the Berkshires center), Kundalini (the heavy-breathing style popularized by Yogi Bhajan, a Sikh mystic), Power (an aggressive form of Ashtanga), and Vinyasa (a flowing style developed relatively late in life by Krishnamacharya and popularized by his student Srivatsa Ramaswami). The subjects had practiced yoga anywhere from two to ten years. They were all white, mostly female, mostly single, and averaged twenty-six years in age. Prior to the study, all had practiced yoga at least twice a week.
The team measured GABA levels before and after an hour-long yoga session. The routine was standardized to focus on asanas and related breathing. At the start and end, the students could engage in brief sessions of quiet contemplation. But they were allowed no extensive periods of meditation or pranayama. The study guidelines called for at least fifty-five minutes of common asanas, such as inversions and backbends, twists and Sun Salutations. To ensure a degree of standardization, a research staff member with yoga training observed the sessions. The scientists compared the eight yoga practitioners to a control group of eleven individuals who did no yoga but instead read magazines and popular fiction for an hour.
The results, published in 2007, fairly glowed. The scientists found that the brains of yoga practitioners showed an average GABA rise of 27 percent. By contrast, the comparison group experienced no change whatsoever. Moreover, the yoga practitioners with the most experience or who practiced the most during the week tended to have real GABA surges. For instance, the practitioner who had done yoga for a decade experienced a GABA rise of 47 percent. One participant who practiced yoga five times a week had an increase of 80 percent, the levels of the neurotransmitter almost doubling.
The scientists concluded that yoga showed much promise for trea
ting anxiety and depression. Perry F. Renshaw, a senior author of the study and director of brain imaging at the McLean Hospital, noted with understatement that any proven therapy that is cheap, widely available, and shows no side effects has “clear public health advantages.”
Encouraged, the team embarked on a new study. This time the scientists looked at nineteen subjects and a control group of fifteen people who walked for exercise, which was seen as having the same metabolic expenditure as yoga. The main subjects had no significant yoga experience. They learned the Iyengar style from scratch and practiced it for three months.
The findings were published in 2010. They showed that even beginning yogis experienced major rises in the neurotransmitter along with improved moods and lessened anxiety. The average GABA rise was less than in the previous study—13 percent versus 27 percent, or about half as much. Still, the new yogis did better than the walkers. And, judging from the evidence, they felt much better about themselves.
Significantly, one of the eleven coauthors of the study was Liz Owen, an Iyengar teacher who ran classes in the Boston suburbs of Cambridge and Arlington. Owen had no doctoral or medical degrees but knew a lot about using yoga to lift moods. “Relax your body,” her website advised. “Nourish your soul.”
During this same period, Khalsa worked hard on studies meant to see if mood adjustment could have demonstrable benefits for diverse careers and life stages. One centered on musicians. Khalsa did his investigation with teachers from Kripalu and focused the research on a renowned establishment just down the road from the Berkshires yoga center—Tanglewood, the summer home of the Boston Symphony Orchestra and its academy of advanced study for young musicians. The goal was to see if doing yoga could help the beginners overcome stage fright in general and, more specifically, perform better for the demanding audiences that came to Tanglewood for summer concerts.
In 2005, Khalsa and Stephen Cope from Kripalu recruited ten volunteers from Tanglewood’s prestigious fellows program. The five men and five women were aged twenty-one to thirty, the average just over twenty-five. They included singers, as well as those who played the violin and viola, horn and cello. For two months, the ten volunteers underwent Kripalu training. The options included morning and afternoon sessions seven days a week, a weekly evening session, an early-morning meditation session, and vegetarian meals at Kripalu. The investigation also included ten fellows recruited as controls who had no yoga training.
The results, though not earthshaking, were encouraging, as Khalsa and Cope reported in their 2006 paper.
The study had assessed performance anxiety that the musicians felt in practice sessions, group settings, and solos. The yogis showed no difference from the control group in practice and group settings but did demonstrate a striking drop in performance anxiety during solos. That made sense, Khalsa and Cope noted. Research showed that such nervousness was low during practice, moderate in group settings, and high in solo performances. So the mood effects, they reasoned, would show up more during solos.
During my visit with Khalsa, we sat in his Harvard office and pored over the Tanglewood results on his computer. A yoga mat was rolled up under his desk. “There’s no question the kids loved it,” he said. “The control group had hardly any change. But look at the yoga groups. Yoga brings you into the moment. It brings a feeling of joy or energy with activity, a kind of mindfulness.”
The results were so positive, Khalsa added, that Tanglewood asked for more. He and Kripalu responded with an expanded study. The young musicians who immersed themselves in yoga, meditation, and Kripalu numbered thirty. And it turned out that their two months of summer practice lifted moods even higher.
In 2009, Khalsa and colleagues reported that the yogi musicians, compared to a control group, showed strong evidence of not only less performance anxiety but significantly less anger, depression, and general anxiety and tension. They loved it, like their predecessors.
Moreover, the scientists tracked down the students a year after the summer program and asked if their lives had changed. Most reported that they had continued doing yoga and meditation, and all said the experience had improved their performance skills.
The portrait of yoga that emerges from decades of mood and metabolic studies is of a discipline that succeeds brilliantly at smoothing the ups and downs of emotional life. It uses relaxation, breathing, and postures to bring about an environment of inner bending and stretching. The actions echo, in a way, how yoga pushes the limbs into challenging new configurations. They promote inner flexibility. As Robin observed, a good workout involves repeatedly pressing the accelerator and brake. Ironically, the overall result is a smoother ride.
No studies have examined the most extreme consequences. But the current evidence seems to suggest that yoga can reduce despair and hopelessness to the point of saving lives. You cannot read Weintraub’s book and learn the details of her turbulent past— cannot watch her doing Breath of Joy, her face lit from within—without feeling the positive force of life affirmation.
If science reveals that yoga can excel at emotional uplift, it also shows that the discipline has a downside. It can do great harm.
IV
RISK OF INJURY
It is no surprise that a field that prides itself on the routine performance of twists, contortions, and dramatic bends of the human body can do a lot of damage. In a similar vein, it makes sense that circus performers—including tumblers and acrobats—also suffer high rates of impairment, and that running, bicycling, and other vigorous sports can result in painful accidents. Even so, yoga injuries are unsettling because of the discipline’s image as a path to exceptional health. Many people turn to yoga as a gentle alternative to exercises that leave them hurt or intimidated. The idea of damage also runs counter to yoga’s reputation for healing and its promotion of superior levels of fitness and well-being. Few practitioners anticipate strokes and dislocations, dead nerves and ruptured lungs.
The good reputation of yoga rests in no small part on the public silence of the gurus. Their virtual ban on the word “injury” made the topic of blinding pain and physical damage almost as unmentionable as Hatha’s origins. Gune made no allusion to injuries in Yoga Mimansa or his book Asanas. Indra Devi avoided the issue in Forever Young, as did Iyengar in Light on Yoga. Silence about injury or strong reassurances about yoga safety also prevailed in the how-to books of Swami Sivananda, K. Pattabhi Jois, and Bikram Choudhury. In general, the famous gurus tend to describe yoga as a nearly miraculous agent of renewal. As one, they imply or state explicitly that ages of practice have shown the discipline to be free of hidden danger.
“Real yoga is as safe as mother’s milk,” declared Swami Gitananda (1907–1993), a popular guru who made ten world tours and founded ashrams on multiple continents.
Modern physicians, on the other hand, have taken an almost malicious delight in recounting the self-inflicted wounds of yoga practitioners and warning of danger, doing so in dozens of reports. Perhaps they are jealous of the admiration accorded to yoga teachers and get a thrill out of challenging yoga’s mystique. Some have gone so far as to condemn yoga as intrinsically unsafe. What takes the edge off some of this criticism—especially during its first appearance—is how it often revealed a lack of deep knowledge about the workings of yoga but nonetheless managed to strike a tone of icy condescension. Even so, the medical professionals lavished attention on yogis who stumbled into their offices and emergency rooms writhing in pain, and wrote up detailed clinical reports on the accidents and injuries.
Like stones cast into a pond, these disclosures produced waves of reaction that in time affected the practice of modern yoga and ultimately helped make it safer—albeit after considerable resistance. Initially, some yogis challenged the reports as biased and mean-spirited. Others, perhaps taken with the mother’s milk argument, tried to ignore the criticism or shrug off the injuries as an inconspicuous cost of doing business.
In recent years, the best teachers have responded to the war
nings with new sensitivity (and better insurance policies). They put safety first, caution their students to proceed with care, and reject the one-size-fits-all mentality of early styles and instructors.
To yoga’s credit, a number of knowledgeable practitioners have recently stepped forward to confront the physical threats quite directly in articles, books, bibliographies, and—most recently—detailed surveys of yoga injuries. The activists are generally reformers who seek to raise awareness of the dangers and offer precautions. The surveys, which can be alarming, suggest that yoga’s recent popularity has created a rush of inexperienced teachers. Ironically, it seems that idyllic vacation spots are particularly treacherous.
Robin is one of the reformers. His books feature lengthy addendums that detail some of the ways in which yoga can go wrong. They tell of paralyzed limbs, bulging eyeballs, damaged brains—among other varieties of destruction, some verging on the bizarre. The appendices reflect his careful reading of the medical literature. They portray a hidden world of major trauma as well as minor problems such as sprains and torn muscles, which turn out to be surprisingly common. In his Pennsylvania class, we practiced a number of precautions, especially on how to unburden the neck in the Headstand and Shoulder Stand.
As a group, the activists tend to be in closer alignment with the findings of science than yoga traditionalists. Just as Robin and his Iyengar colleagues have redesigned the Headstand, some of the reformers have focused on reinventing some of the most dangerous poses or advising students to drop them altogether.
Such reevaluations may go against yoga’s timeless image. But as we have seen, yoga has proved itself quite flexible in adapting to the needs and desires of different ages. Today, the long silence of the gurus has given way to scientific inquiries that are nurturing new strategies for injury prevention. The reform movement is a happy case study in what can happen if yoga and science cooperate, even grudgingly. The inconspicuous wave of reinvention promises to benefit millions of students around the globe and, not insignificantly, to help modern yoga live up to its good reputation.
The Science of Yoga: The Risks and the Rewards Page 14
