The Science of Yoga

was sixty.
    Despite the wishful thinking, a recent discovery suggests that yoga can indeed slow the biological clock. The finding centers on a long-standing riddle—why cells age, die, or in some cases defy the natural order of things to remain young. The answer involves the microscopic whorls of DNA that lie at the tips of the chromosomes, the central repositories of genetic information in the cells. Scientists have found that these DNA tips, known as telomeres, get shorter each time a cell divides and thus serve as a kind of internal clock that determines the cell’s allotted time in life. They have also discovered the secrets of telomere growth and youthfulness. The finding was considered so important that it won the 2009 Nobel Prize in Physiology or Medicine. To scientists, the story of the telomere suggested a more accurate way of measuring biological age than simply marking the passage of the years.
    As often happens in science, the discovery brought into sharp focus yet another question—why do the telomeres of some individuals hold up much better than others? In some cases, an eighty-year-old could have the long, youthful telomeres of a thirty-year-old. Why the variation?
    It turned out that a number of everyday conditions eroded the telomeres—a main one being chronic psychological stress. (Other factors include unhealthy diets and infections.) Happily, science also found that reducing stress could slowthe biological clock. The slowdown was found to work even with subjects well into their middle and later years. Perhaps most intriguingly, given humanity’s long search for a fountain of youth, a few tentative studies suggested that short telomeres could be coaxed into growing long again, in effect turning back the biological clock.
    Enter yoga. Science over the decades has repeatedly shown yoga’s talent for undoing physical and mental stress, as we will discuss in chapter 3. Thus yoga, despite its checkered history on longevity claims, appears to be custom made for slowing the biological clock.
    Dean Ornish led the appraisal. A Harvard-trained physician known for his popular books, Ornish was a longtime devotee of yoga, having begun his practice in the 1970s. Over the years, he developed and marketed a health plan that championed a combination of yoga, low-fat diets, whole foods, and relaxation techniques. Studies of his method became part of the evidence for yoga’s cardiovascular benefits. Now he turned his attention to the telomeres, in particular to a measure of their maintenance and building known as telomerase—an enzyme that adds DNA at the chromosome tips. He did so with colleagues from the University of California at San Francisco, including Elizabeth Blackburn, who was soon to share the Nobel Prize for her telomerase findings.
    The team looked at twenty-four men who took up the Ornish program. They ranged in age from fifty to eighty and did yoga for an hour a day, six days a week. The scientists assessed telomerase levels and other physical and psychological measures before the men began their overhaul and did so again at the conclusion of the three-month program. The results were unambiguous. The scientists found declines in cholesterol, blood pressure, and such indicators of emotional distress at disturbing thoughts. More important, they discovered that levels of telomerase shot up 30 percent.
    The team reported its findings in late 2008, proclaiming them a first. The eleven scientists said the findings had implications for cellular longevity, tissue renewal, disease prevention, and “increases in life span”—a holy grail of modern science.
    The Ornish inquiry was only a beginning, of course. Other investigators would have to zero in on yoga practitioners and do larger and more elaborate studies. But it was a start.
    As science over the decades succeeded in promoting healthover the miraculous, some yogis nonetheless managed to cling tenaciously to the past and show a recurring fondness for discredited myths. Major gurus gave up wild declarations. But other authorities were often quick to embrace lesser miracles and trendy fictions.
    The Complete Idiot’s Guide to Yoga proclaimed that yogis can “live to be well over 100 years” and can “stop their own hearts (then start them again, of course).”
    So, too, Georg Feuerstein, a star of yoga scholarship, concluded that science “lent credibility to many” of yoga’s more astonishing claims, making them “appear far less