The Science of Yoga

Controls let scientists zero in on a single variable and avoid subtle misunderstandings. They try to eliminate the complexities of nature and human interaction to ensure that anyobserved changes are the result of the examined factor rather than some extraneous influence. With the Duke study, for instance, the experimental controls let the scientists make sure that the process of simply gathering the subjects to the site of the investigation played no role in the results. What if some walked there? What if some bicycled? What if some ran? Would that affect the fitness measurements? The changes observed in a control group could alert scientists to the existence of an unintended influence and help them eliminate it from their findings. The big challenge for a scientist designing a study with human subjects is to make the experiences of the experimental and control groups as similar as possible—with the exception of the issue under examination. Without such precautions, researchers have no way of knowing whether the changes observed in an experiment would have happened anyway. The practical difficulty of such precautions is their added expense. The recruitment of more subjects—and their subdivision into different kinds of activities—can result in the need for more money, more personnel, more data analysis, and more administrative burdens. But the scientific benefits are usually seen as worth the costs.
    In the Duke study, the hundred or so subjects, including the control group, did their designated activities for a total of four months. To get around the measurement dilemma, the team made no readings during the months of assigned activities and instead opted for detailed assessments before and after the training.
    The results, published in 1989, were unambiguous. The aerobics group improved its VO 2 max significantly, raising peak oxygen consumption by 12 percent. But the yogis showed no increase whatsoever and in fact registered a bit of a decline, though it was judged to be statistically insignificant.

    A surprise also emerged.The scientists were intrigued to discover that the yogis, despite their poor showing in terms of aerobic conditioning, nonetheless felt better about themselves. The subjects reported enhanced sleep, energy, health, endurance, and flexibility. They described how they experienced a wide range of social benefits, including better sex lives, social lives, and family relationships. Psychologically, the scientists said, the yogis reported a number of improvements. They had better moods, self-confidence, and life satisfaction. With few exceptions, they said they looked better.
    The Duke findings hinted at a fascinating split. It was one thing to do good for the hidden intricacies of human physiology and quite another for an individual to feel good about themselves. It was the difference between improved fitness and outlook. The subjects who did yoga felt they had received a wealth of benefits even though the Duke scientists found no indication whatsoever of aerobic gains. Their discussion of the research findings hinted at their fascination. The improvements in attitude, the scientists said, “are worth noting.”
    The Duke team—unknowingly—had stumbled on one of yoga’s secrets. The next chapter will explore the science of how the discipline lifts the human spirit.
    Yoga fared slightly better in subsequent studies of aerobic conditioning. One reason was a subtle change in the discipline that put growing emphasis on energetic poses and styles. The new forms downplayed stationary postures for ones that required a much greater level of movement and physical activity, creatinga more athletic experience and increasing the aerobic challenge.

    Sun Salutation, Surya Namaskar
    To a surprising degree, the new vigor centered on a single activity— Surya Namaskar, Sanskrit for “salutation to the sun.” Today it is one of yoga’s most popular poses. The student, rather than remaining motionless in a fixed posture, moves through a fluid series of up to a dozen interconnected poses that go from standing to bending to lying prone to standing back up and to stretching backward. If done rapidly—and repeatedly—the sequence can leave the heart pounding and the lungs gasping for air. It therefore has elements of a cardiovascular workout.
    The Sun Salutation and its relatives are, by nature, quite malleable. They can be sped up or slowed down to suit individual preferences. In their adaptability, they