The Science of Yoga: The Risks and the Rewards (13 page)

Sun Salutation,
Surya Namaskar

To a surprising degree, the new vigor centered on a single activity— Surya Namaskar, Sanskrit for “salutation to the sun.” Today it is one of yoga’s most popular poses. The student, rather than remaining motionless in a fixed posture, moves through a fluid series of up to a dozen interconnected poses that go from standing to bending to lying prone to standing back up and to stretching backward. If done rapidly—and repeatedly—the sequence can leave the heart pounding and the lungs gasping for air. It therefore has elements of a cardiovascular workout.

The Sun Salutation and its relatives are, by nature, quite malleable. They can be sped up or slowed down to suit individual preferences. In their adaptability, they are quite different from yoga’s static postures. The situation is similar to what we experience in terms of gait. When standing motionless, we are, by definition, stationary. But once in motion, we can move forward in a number of ways: walking, jogging, running, or racing ahead as fast as we can. It depends on what we want to do.

The Sun Salutation appears to be fairly recent in origin. The
Encyclopedia of Traditional Asanas
—published in India by the Lonavla Yoga Institute, founded near Gune’s ashram by one of his students—draws on nearly two hundred books and unpublished manuscripts to describe many centuries of pose development but says nothing about the Sun Salutation. So, too, the asana makes no appearance in the how-to guides of Gune (1931), Sivananda (1939), and other early teachers.

The pose most likely arose in the early twentieth century as the Mysore palace and Krishnamacharya mixed traditions of British gymnastics and native wrestling. Whatever its exact origins, the Sun Salutation debuted as an important new feature of Hatha yoga in the 1930s, spreading slowly through India and the world. The idea behind the pose and kindred postures was what Krishnamacharya called Vinyasa (
vi
denotes “in a special way” and
nyasa
“to place”). It stood for the flowing movements that he developed to join the individual poses into a new kind of graceful activity. The result was a kind of yoga ballet.

In the West, students of yoga learned about the pose in a number of ways. Krishnamacharya’s student Sri K. Pattabhi Jois played an important role in popularizing the series of movements and the Vinyasa system, calling it Ashtanga
(or eight-limb) yoga, after the sutras of Patanjali and their eight rules. Starting in the late 1960s, Westerners began traveling to Mysore to study yoga with Jois. Slowly Ashtanga grew in popularity, especially among the physically ambitious in the West who were seeking yoga’s most athletic expressions. The aggressive style required skill and power, and could leave a student bathed in sweat.

Science looked into Ashtanga as the style gained in popularity and found that, compared to traditional yoga, it posed a greater challenge to the heart. One study examined sixteen volunteers. The human heart beats about seventy times per minute. On average, the hearts of the yogis quickened to ninety-five beats while doing Ashtanga, compared to eighty beats during conventional Hatha. The Ashtanga factor represented a rise of roughly 20 percent.

The more difficult question was whether the increased thumping of the heart that resulted from faster poses and faster styles translated into measurable improvements in cardiovascular fitness. That soon became
the
question.

Ezra A. Amsterdam was hitting new highs in his career when yoga caught his eye. A senior cardiologist at the medical school of the University of California at Davis, he had devoted himself to the study, practice, and teaching of ways to prevent heart disease, the nation’s number one killer. He was prolific. His résumé boasted hundreds of articles. Recently, he had even founded a journal—
Preventive Cardiology
—the first of its kind, published by John Wiley & Sons, a respected firm. Amsterdam’s own studies ranged from investigations of diet and exercise to drugs and therapy as ways to promote a healthy heart and fend off cardiovascular disease. He lived in sunny California and practiced what he preached, maintaining a trim figure into his sixties.

Yoga as a field of scientific inquiry seemed wide open to Amsterdam, his interest stimulated by what he saw as “the lack of objective study.” Growing numbers of people were practicing yoga, and doing so in new, innovative ways that were often quite vigorous. A fresh look at the relationship between yoga and aerobics seemed to beckon.

Another factor was his daughter. Dina suffered from an eating disorder and was twenty-five pounds overweight when she starting doing yoga. It worked like a charm. The discipline helped her shed weight, feel good about herself, and
get in excellent shape. She studied with Rodney Yee, a yoga star, taking his advanced teacher training course. Dina became a devotee of the discipline and proceeded to teach classes in the San Francisco area. She had a big smile and a reputation for rigor, sensitivity, and infectious enthusiasm. Dina—a graduate student at Stanford University—also had a deep interest in the science of yoga and wellness. She had “many lively discussions” with her father, she recalled, and was delighted when he decided to do a yoga study.

Amsterdam was determined to give yoga a serious look. Was the discipline all that it was cracked up to be? Was it, in fact, all that Dina needed to stay fit, to maintain a healthy heart? Could any practitioner reap the benefits? If so, yoga might join the elite club of rigorous sports and activities that public health authorities had singled out as highly beneficial—especially in preventing heart disease and the kind of cardiovascular illnesses that Amsterdam knew only too well.

He worked with a team of specialists from the University of California at Davis, a good school in a highly respected system. Except for him, the three researchers came from the department of exercise science, anchoring the study in a solid analytic tradition. In terms of capabilities and intellectual depth, the team appeared to be quite strong.

But the investigation, begun on an auspicious note, soon encountered a number of difficulties. The biggest was the lack of major financial support for the study, which forced the scientists to limit its size and design. They lined up just ten volunteers—one man and nine women. Compared to the Duke study, that was one-tenth the number of subjects. Moreover, their examination had no control group. The low numbers and the absence of controls increased the possibility that any observed changes might result from random variability rather than yoga. A final limitation was that the students were required to do a minimum of just two workouts a week for two months—a fairly short time in which to see the physiological effects of yoga. By contrast, the Duke study had proceeded twice as long.

Even so, the yoga session itself was fairly intense, lasting nearly an hour and a half. It included ten minutes of breathing exercises (pranayamas), fifteen minutes of warm-up exercises, fifty minutes of yoga postures (asanas), and ten minutes of relaxation in the Corpse pose (Savasana). A centerpiece was the Sun Salutation. The students did two or three cycles of
its fluid movements, stretching and bending back and forth. In addition, the workout featured a number of other vigorous moves that went beyond yoga’s tradition of stationary poses. They included lunging forward on the legs and bobbing up and down in what the investigators called the Frog.

Different schools of yoga mean different things when they talk about the posture. The energetic pose adopted by the Davis team was a newcomer to yoga, its origins unclear. No classic text mentions its repetitious movements. It starts with students squatting down, putting their hands on the floor, and then straightening out their legs. While raising their bottoms high in the air, they keep their heads as close as possible to their knees. The movement ends with the students lowering themselves back down into the squat. Modern texts that describe that style of Frog recommend doing it anywhere from fifteen to more than one hundred times, its rhythms growing increasingly fluid and fast as the student warms up.

The ten volunteers in the Davis study had led fairly sedentary lives. A condition for participation in the study was that they had engaged in no regular physical activity—including yoga—for the previous half year. Moreover, the researchers had the students refrain from all other forms of exercise. As with the Duke study, the researchers got around the measurement problem by performing the physiological assessments before and after the yoga training.

Having gathered and analyzed the data, the Davis team got ready to present its findings to the world. That meant finding a reputable journal.

Not all public representations of science are created equal. Journals range from bad to great. A minimum requirement for a good journal is that it conducts a process known as peer review—that is, it maintains panels of scientists working in the field who review any proposed article. They exercise what amounts to quality control, making sure a submission hangs together and, if weak, gets rejected or revised to address the inadequacies. Some of the world’s best journals are published by professional associations and have long histories.
Science
, for instance, was founded in 1880 with the financial support of Thomas Edison and is now published by the American Association for the Advancement of Science, a large professional group headquartered in Washington. The best journals—the ones most widely accepted and admired within the scientific community—achieve
good names by virtue of long histories of responsible reporting, quality articles, and exhaustive peer review.

In 2001, the Davis team laid its findings before the world. It did so not in a sports journal, not in a physiology journal, and not in a general-interest journal of good reputation, such as
Science.
Instead, it reported the yoga findings in
Preventive Cardiology
, the journal that Amsterdam had recently founded and on which he served as editor in chief.

In theory, his editorial control did nothing to diminish the study’s credibility. The journal, after all, was peer reviewed. Amsterdam told me that the manuscript was sent to several reviewers with whom he had no relationship, making their evaluation “blind” and unbiased. Moreover,
Preventive Cardiology
was the official journal of the American Society for Preventive Cardiology, a professional group. Still, a situation in which the most important gatekeeper at a journal also submits his or her own work for publication can foster a perception of a conflict of interest. Did reviewers go easy on the manuscript to curry favor? Did the editor have a financial stake in the journal’s success, and thus an incentive to make bold claims that would draw wide attention, raising the journal’s readership?

A related problem centered on the sheer magnitude of Amsterdam’s submissions.
Preventive Cardiology
carried so much of his own work that the journal, despite its professional affiliation, seemed less like an impartial forum than a vanity press. The same issue that featured the yoga study carried another one of his papers. In all, the quarterly journal that year published four of his articles. No other author came close. His work, except for the yoga study, focused on medical aspects of heart disease.

That led to a final topic of procedural significance—whether
Preventive Cardiology
was the right place for the yoga study. The Davis team reported a range of athletic findings, not just ones related to the heart. It seems like its natural home would have been an athletic forum, perhaps the
Journal of Exercise Physiology.
But the authors, for whatever reason or reasons, instead chose the pages of
Preventive Cardiology
.

The study came across as strong and authoritative. For instance, the Davis scientists reported that the fledgling yogis racked up solid gains in muscular strength. One test centered on knee extension—the act of straightening out the leg while raising a heavy weight. On average, the students improved 28 percent.
They also showed greater flexibility. On average, they increased the amount they could bend forward (as in the Frog) by 14 percent. Their backward stretches (as in the Sun Salutation) improved even more, rising on average nearly 200 percent.

Unfortunately, the gains in aerobic conditioning—the primary interest of Amsterdam the cardiologist—were quite small. Even so, the Davis scientists judged them to be statistically significant. They reported that VO
₂
max rose on average 7 percent. Moreover, they judged that the positive finding stood out from all previous studies, marking a milestone in the scientific evaluation of yoga.

“The present study,” the authors declared, “is the first to show improvements in cardiorespiratory endurance by direct measurements.” The scientists concluded that the overall results of their study indicated that Hatha yoga “would meet the objectives of current recommendations to improve physical fitness and health.”

That was a big claim for what was indisputably a small investigation—for what its authors conceded was a “pilot study” that amounted to a preliminary look in search of noteworthy trends. The scientists offered no comment on how the small observed gain in aerobic conditioning measured up to the official recommendations of such groups as the American College of Sports Medicine, although their use of the conditional tense, “would meet,” bespoke caution.

Nor did the authors put the aerobic figure into a wider context. They made no comparison of the 7 percent rise to what a sedentary individual might gain from endurance training, where scientists had found that peak oxygenation could increase up to 50 percent.

“In summary,” the Davis scientists said, “the results of this investigation indicate that eight weeks of Hatha yoga practice can significantly improve multiple health-related aspects of physical fitness.”