The Science of Yoga

science’s understanding of yoga, Dostálek argued. A number of investigators and studies had come to view the discipline as strictly calming and relaxing, seeing its methods as producing “states of lowered autonomic arousal and EEG deactivation.” But that was only half the picture, he argued. The other half told of excitation. His own studies, Dostálek said, revealed the magnitude of the stimulation. He noted that yoga’s physiological arousals were associated mainly with the kinds of practices and fast breathing described in Hatha Yoga Pradipika and Gheranda Samhita.
    Still, in his theorizing, Dostálek hewed to the conventional line. He portrayed the highs as simply helping the body gain new physiological flexibility, letting it not only rise to new heights but to hit new lows. Yoga worked in the main, Dostálek argued, to promote relaxation, unwinding the sympathetic overstimulations of modern life. Ultimately, he saw yoga as a sedative.
    A few scientists glimpseda different world. Their examinations of advanced yogis suggested that deep relaxation, rather than an end in itself, could represent a calm stage on the road to a remarkable kind of continuous arousal. Their subjects displayed clear signs of autonomic stimulation while lost in blissful trances. The studies were relatively few in number. But they were ample enough to suggest that, at least in some comparatively rare cases, the kind of fleeting arousals that Dostálek had documented could endure.
    James C. Corby, a psychiatrist at the Stanford University School of Medicine, did the most thorough study of this hidden world. His team looked at twenty members of a Tantric sect known as Ananda Marga, or “path of bliss.” The group, founded in India, treads a steep path. In addition to doing asanas, pranayama, and many austerities, the initiates meditate for long periods. The scientists recruited equal numbers of trainees and experts. On average, the expert Tantrics, all from the San Francisco area, meditated for more than three and a half hours a day and had done so for years. In their study, the Stanford team noted that practitioners often reported feeling rushes and bursts of energy during their meditations. The scientists also recruited ten inexperienced individuals to act as a control group.
    Each subject sat alone in a dimly lit room during the monitoring sessions, which lasted an hour. The scientists had all the participants—whether controls, trainees, or experts—perform the same routine. The participant would spend twenty minutes relaxing, twenty minutes paying attention to their breathing, and twenty minutes meditating. The controls used two-syllable mantras they made up, while members of Ananda Marga used their personal mantras.
    Corby and his team studied not only the brain waves of the participants but their heartbeats, breathing rates, and skin conductance. The latter was an important sign of emotional arousal and, in some cases, sexual excitement. Scientists have long known that sweat causes the electrical conductivity of the skin to rise, and have long viewed it as an indication of sympathetic arousal. In the early days of conductivity studies, scientists monitored the skin response as a way to probe the unconscious. So, too, scientists developed lie detectors as a way to measure skin conductivity for clues asto whether a person was relaxed and telling the truth or clammy and deceitful.
    The Stanford team found that the Tantric experts and trainees displayed solid evidence of autonomic arousal. The signs included fast heartbeats and significant rises in skin conductance. The control group, on the other hand, showed signs of overall relaxation.
    In one case, a woman Tantric sent the measurements flying off the charts when she experienced what she later described as “near samadhi”—the ecstatic state of enlightenment. While meditating, her skin conductance soared and she began to breathe fast and her heart rate shot up to more than one hundred and twenty beats per minute—equal to that of frenzied lovers. Abruptly, she stopped breathing altogether and her heartbeat slowed as well. Finally, after more than a minute and a half in which her chest remained virtually motionless, she began to breathe normally.
    “We were extremely fortunate,” Corby’s team wrote, to observe the woman’s experience.
    Corby and his colleagues said nothing about sexual arousal. They used phrases such as “physiological activation” and