The Science of Yoga

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.

III
MOODS
    S at Bir Khalsa chatted amiably as we walked down the street. His beard was long and gray, his turban white, and his bracelet made of steel—all signs of his Sikh religion. He was not, however, Indian. Born in Toronto of European stock, he had converted to Sikhism decades ago upon taking up Kundalini Yoga, an energetic form that emphasizes rapid breathing and deep meditation.
    No one on Longwood Avenue seemed to give the turbaned Sikh a second look. Boston that spring day was gorgeous. An early shower had scrubbed the air, leaving it awash in sunlight. Flowers and trees were blooming. Men and women were shedding their coats. People fairly hummed along the sidewalks.
    We had just eaten lunch at Bertucci’s, a bustling restaurant where Khalsa had finished his meal with bomba —“the bomb” in Italian. The dessert consisted of balls of vanilla and chocolate gelato dipped in chocolate and covered with almonds, whipped cream, and chocolate sauce. I could see why his kids loved the place.
    Maybe it was the sugar high, or the beautiful day, or the yoga. Whatever the cause, the air fairly pulsed as Khalsa—a faculty member at the Harvard Medical School and one of the world’s leading authorities on the science of yoga—laid out his findings and ambitions. The friendly man of fifty-six turned out to have a lot.
    At Harvard, Khalsa had pursued a bold program of research that explored how yoga can soothe physically and emotionally. His focus was practical—and structured that way deliberately to demonstrate yoga’s social value. He had examined how its powers of unwinding can promote sleep and ease performance anxiety among musicians, and was now organizing a study to see if its calming influence could help high school students better fight theblues and everyday stress. Khalsa had ten yoga investigations in various stages of development.
    With energy and articulate zeal, he described his research as a way to help yoga break from its fringy past and go mainstream.
    “What ever happened to mental hygiene?” he asked rhetorically. “It doesn’t exist—and never did. When you went through high school, you were never taught how to deal with stress, how to deal with trauma, how to deal with tension and anxiety—with the whole list of mood impairments. There’s no preventive maintenance. We know how to prevent cavities. But we don’t teach children how to be resilient, how to cope with stress on a daily basis.
    “There’s a disconnect,” he continued. “We’ve done dental hygiene but not mental hygiene. So the question is, ‘How do we go from where we are now to where we need to be? ’ ”
    Khalsa argued that the only way to convince people about the value of yoga and establish a social consensus that encouraged wide practice was to conduct a thorough program of scientific research. He added that recommendations for regular toothbrushing had started that way and illustrated the potential value of good yoga studies.
    “That’s my mission in life,” Khalsa told me.
    This chapter examines not only Khalsa’s research but many inquiries into how yoga can lift moods and refresh the human spirit. It starts with the earliest research and ends with the most recent. The arc of the narrative is really a detective story. The studies began with the muscles (and how yoga can relax them), went on to study the blood (and how yoga breathing can reset its chemical balance), and eventually zeroed in on the subtleties of the nervous system (and how yoga poses can fine-tune its status). The discipline was found to lift and lower not only emotions but also their underlying constituents—the metabolism and the nervous system.
    The mood benefits detailed here are very real, unlike some of the aerobic claims of the last chapter. But the field also