The Science of Yoga

Paul suggested, many aspects of yoga reinforce slow breathing and limit the exhalation of carbon dioxide, including the repetition of mantras and chants. In 2001, Luciano Bernardi, a medical internist at the University of Pavia, in Italy, reported on a study of nearly two dozen adults. His team found that the repetition of a mantra cut the normal rate of respiration by about half, reinforcing mental calm and producing an enhanced sense of well-being.
    In short, science over the decades has learned a lot about how yoga breathing affects a person’s mood and underlying metabolic state. Fast styles tend to excite and slow ones to calm.
    And it has nothing to do with getting more or less oxygen into the practitioner’s body, contrary to innumerable yogis and gurus, video discs and yoga books, blogs and newsletters. Nevertheless, some yoga authorities go so far as to issue delusional warnings.
    “You’re not used to so much oxygen pouring into your system!” Choudhury, the guru of hot yoga, cautions students who do his deep breathing and begin to feel dizzy. He says nothing of big carbon dioxide drops, the real cause of blackouts.
    The blunders go on and on. Breath of Fire “increases oxygen delivery to the brain,” said Kundalini Yoga , richly illustrated and highly accessible to beginners. Actually, as we just saw, it does the exact opposite, dramatically so.
    The Complete Idiot’s Guide to Yoga praises the discipline’s breathing as “one of the best things you can do to keep your body filled with oxygen.” The advertisedeffects sounded a lot like the calm serenity that high carbon dioxide levels can induce.
    The confusion about yoga breathing as a way to fill the body and brain with oxygen goes far beyond simple misstatements and their dissemination through countless books, articles, and videos. Of late, it has spread to a whole new style of the discipline. Oxygen Yoga promotes itself as beneficial “for anyone in need of more oxygen.” Its authors have a line of books. The newest— Oxygen Yoga: A Spa Universe , published in 2010—recommends that health resorts adopt the style for “added revenue.”
    It is said that every disaster has a silver lining. In a similar way, the failure of yoga investigators to find miracle workers who could stop their hearts and live without air led to a major advance in understanding the brain. And that discovery in turn revealed one of the most important ways that yoga can sway emotion. It happened in the decades after Behanan did his experiments, from roughly the 1940s to 1970s.
    The lesser discoveries ended up revising a major tenet of the medical world—that the human body has two nervous systems that are entirely distinct. The newer one starts in the outer brain and radiates out in the nerves that let us move our skeletal muscles and go about our daily lives. The older one begins in the lower brain and regulates the internal muscles, the organs, the instincts, and other primal functions. It is called the autonomic nervous system.
    The medical credo of the day held that its activities were automatic and, with notable exceptions (such as breathing), beyond the control of the conscious mind. But scientists who studied gifted yogis kept documenting abilities that contradicted this tidy picture. In study after study, they found that yogis could seize control of autonomic functions and make dramatic changes of body activity. The automatic system, it turned out, contained options for all kinds of manual overrides.
    One of the scientists was Thérése Brosse, a French cardiologist who examined Krishnamacharya. She and her colleagues wrote extensively on how advanced yogis could unwind in surprising ways, slowing the heart rate and blood flow. Another was Bagchi. Despite his campaign to expose yogic miracles as false, he documented wide yogic control over autonomic functions once considered beyond reach. A 1957 paper of his found “an extremeslowing” of such fundamentals as respiration and heart rate. He concluded that overall, yoga brings about “deep relaxation of the autonomic nervous system.”
    The star of autonomic control was an Indian yogi named Swami Rama. Among other things, laboratory studies showed that he could use his mind alone to change the temperature of his hand, creating a gap of up to eleven degrees across his palm.
    The autonomic system is bifurcated, and the studies showed that advanced yogis could seize control of either side. The sympathetic side