The Science of Yoga

emphasis in Hatha Yoga from Pacific Western University.” The school might have had no foreign language requirement or classroom challenges, but its message was relentlessly upbeat: “Look within yourself,” the school told prospective students. “Exert yourself with dynamic will power through positive thinking and persistence and you will stretch your talents and imagination and achieve new heights of learning while attaining professional and personal success.”
    Payne did just that. He became a whirlwind. Armed with his new credentials, he gave lectures, wrote books, made instructional videos, appeared on radio and television shows, and, in 1989, helped found the International Association of Yoga Therapists. As its founding president, and later its director and chairman, he enjoyed a new world of global influence. The group began its journal in 1990, and Payne worked hard in his new job to drum up new readers and memberships.
    Bigger things beckoned, and in 1999 Payne entered the burgeoning field of popular yogabooks. Yoga for Dummies featured his Ph.D. prominently on the cover, along with that of his coauthor, Georg Feuerstein. As a team, Payne covered yoga’s modern aspects while Feuerstein, an Indologist, handled its ancient ones. The twin credentials lent the book an air of authority and set it apart from competitors, although its biographical materials gave no indication of where Payne received his doctorate or in what field. The book identified him as chairman of the International Association of Yoga Therapists and a yoga teacher with a thriving practice who “responds to his clients’ specific health challenges,” implying that he was a credentialed healer. At a minimum, many readers probably assumed that his doctorate—ostensibly a proof of high academic standing—meant that the book reflected the best understanding of modern science.
    The truth lay elsewhere.
    The chapter on yoga breathing distinguished itself for its repeated praise of supplemental oxygen as a secret of yoga’s powers. Deep inhalation, it declared, “loads your blood with oxygen.” Three pages later, Yoga for Dummies enlarged on the error. Pranayama, it said, “allows you to take in more oxygen food for the 50 trillion cells in your body.” That, of course, not only described a false oxygen rise but made the claim sound more authentic by linking it to the striking body-cell figure.
    Two pages later, the book goofed again. After reminding the reader that yogic breathing “brings more oxygen into your system,” Dummies raised a red flag. “Don’t be surprised,” it warned, “if you feel a little light-headed or even dizzy.” That explanation, of course, went to the repercussions not of adding oxygen but of blowing off carbon dioxide, which can result in blackouts. It was another missed opportunity for understanding.
    The trend culminated with the description of a breathing exercise that, the book assured, would “treat your body with oodles of oxygen.” All the body’s cells, it emphasized, “will be humming with energy and your brain will be very grateful to you for the extra boost.”
    Payne’s book also managed to misrepresent one of the most fundamental ways in which yoga affects the human body. As we have seen, scientific investigators, starting in the nineteenth century, established that a defining characteristic of yoga—perhaps the defining characteristic—is how it can slow the body, the mind, andthe overall metabolism to foster tranquility. Paul focused on hibernation, Behanan on the “retardation of mental functions,” Bagchi and his colleagues on the “extreme slowing” of respiration and heart rates, Bera and his colleagues at Gune’s ashram on lowered metabolism, many scientists on the body’s parasympathetic brake, and Benson on wide physiological drops that led to hypometabolism. Yes, a few breathing styles—such as Bhastrika and Kapalbhati—can excite. But overall, they are the exception, not the rule. As the team of Indian scientists in Bangalore reported, the regular practice of yoga causes the resting metabolic rate to fall.
    This physiological fact of life has an obvious social proof. Yoga has won a global following not because of some ostensible ability to zip people up but by its demonstrated power to slow them down. It has proved extraordinarily effective at undoing urban stress and the tensions of modern life. The reason yoga studios are so ubiquitous in big cities is because