The Science of Yoga

percent. Their backward stretches (as in the Sun Salutation) improved even more, rising on average nearly 200 percent.
    Unfortunately, the gains in aerobic conditioning—the primary interest of Amsterdam the cardiologist—were quite small. Even so, the Davis scientists judged them to be statistically significant. They reported that VO 2 max rose on average 7 percent. Moreover, they judged that the positive finding stood out from all previous studies, marking a milestone in the scientific evaluation of yoga.
    “The present study,” the authors declared, “is the first to show improvements in cardiorespiratory endurance by direct measurements.” The scientists concluded that the overall results of their study indicated that Hatha yoga “would meet the objectives of current recommendations to improve physical fitness and health.”
    That was a big claim for what was indisputably a small investigation—for what its authors conceded was a “pilot study” that amounted to a preliminary look in search of noteworthy trends. The scientists offered no comment on how the small observed gain in aerobic conditioning measured up to the official recommendations of such groups as the American College of Sports Medicine, although their use of the conditional tense, “would meet,” bespoke caution.
    Nor did the authors put the aerobic figure into a wider context. They made no comparison of the 7 percent rise to what a sedentary individual might gain from endurance training, where scientists had found that peak oxygenation could increase up to 50 percent.
    “In summary,” the Davis scientists said, “the results of this investigation indicate that eight weeks of Hatha yoga practice can significantly improve multiple health-related aspects of physical fitness.”
    It was, arguably, a small step for the recognition of yoga as an aerobic activity—a step grounded in the discipline’s growing incorporation of such vigorous poses as the Frog and the Sun Salutation. Or perhaps it was simply a fluke. The lack of experimental controls increased the chance of false readings.
    Whatever the study’s scientific merit, the leaders of the yoga community, long on the defensive when it came to cardiovascular issues, seized on the modestfinding as a breakthrough. It was hard proof, they asserted, that yoga is all an individual needs to stay fit. The contention was a bold restatement of Gune’s early claims. Only now—in theory, at least—it had the steel of modern science.
    A portrait of the aerobics research formed the heart of a 2002 article in Yoga Journal. The glossy magazine prides itself on giving readers “the most current scientific information available.” It spread its lengthy cover story on yoga fitness over nine pages and illustrated it with lots of color photographs of yogis in scientific labs undergoing close scrutiny. A main location for the documentary photos was the University of California at Davis. In its article, Yoga Journal reported that it had carefully surveyed the world of science and discovered solid evidence that “optimal fitness” requires no running or swimming to strengthen the heart and no weight lifting to build the muscles.
    “Yoga is all you need,” it declared, “for a fit mind and body.”
    The article said nothing about the downbeat findings of Cooper and the Duke scientists. It did, however, highlight the Davis study, calling the 7 percent rise “a very respectable increase” and hailing the aerobic finding as a breakthrough. Even so, the article, like the Davis authors, provided little context for the figure—making no comparison, for instance, to what endurance training can do for peak oxygenation.
    Reaching further, Yoga Journal filled its article with profiles, testimonials, and anecdotal studies of people who hailed the yoga-alone perspective.
    It quoted Dina Amsterdam. “I haven’t done anything but yoga and some hiking for ten years,” she said. “Yoga completely brought me back to physical and emotional health.”
    The Davis and Yoga Journal articles quickly became the go-to authorities around the globe for demonstrating that yoga alone was vigorous enough to meet the aerobic recommendations. The door had opened a crack, and a blast of aggressive marketing shot through.
    One of the flashiest promoters was YogaFit, a commercial style that originated in Los Angeles. Its founding goal was to make yoga an integral part of the fitness industry. The style combined push-ups,