The Science of Yoga

some of the married men more than doubling. On average, the levels rose 57 percent. The results, the scientists wrote in 1974, suggested that yoga could prompt a “revitalization of the endocrine glands.” As for the mechanism, they speculated that yoga had improved the microcirculation of the blood through the men’s organs. In males, testosterone is made primarily in the testes but also to a lesser extent in the adrenal glands. It seems that poses such as the Bow, which exerts pressure on the genital region, might well serve as a stimulus to improved circulation.

    Bow, Dhanurasana
    In 1978, Udupa published a summary of the hormone findings in his book Stress and Its Management by Yoga. He noted the clinical evidence of the testosterone rise and attributed it to “considerable improvement in the endocrine function of the testes.”
    His hunch had proved correct. But Udupa made little of it. His finding was a particle of basic science in a blizzard of global research.
    Living peacefully on theGanges a couple of hundred miles downstream from Benares and Udupa were advanced yogis who displayed a strong interest in science, their guru having named their ashram the Bihar School, after its location in Bihar state. It turns out they were interested in learning as well as teaching. A swami writing in Yoga Magazine , published by the school, called attention to Udupa’s testosterone finding. His brief reference was buried in an overview of Udupa’s yoga research. Still, the author, steeped in British English, noted how the hormone discovery suggested that yoga postures could improve “vitality and sexual vigour.”
    His appraisal was clear-eyed but rare. For the most part, science as well as popular and yogic literature ignored the finding. The Bihar yogis noted the testosterone rise in 1979, shortly after the publication of Udupa’s book. It seems plausible that the finding caught their attention not only because of their proximity to the research but because their own experiences had convinced them of its physiological truth.
    If science ignored the finding, investigators nonetheless threw themselves into acquiring a better understanding of testosterone. In Udupa’s day, the potent hormone was seen mainly as the force behind the male sex drive. Scientists knew that its levels fell with age, and that rises could lead to revitalization.
    But over the years, modern biology found many other ways in which the little molecule can influence behavior and sexuality—doing so in both males and females. Not the least significant, studies showed that it acts to improve mood and a person’s sense of well-being. It seems likely that the hormone forms a significant part of yoga’s cocktail of feel-good chemicals.
    Importantly, testosterone was shown to bolster attention, memory, and the ability to visualize spatial tasks and relationships. It sharpened the mind.
    Surprisingly, testosterone also turned out to play an important role in female arousal. While adult males tend to produce ten times more testosterone than females, scientists found that women are quite sensitive to low concentrations of the hormone. They make it in their ovaries and adrenals, and its production peaks around the time of ovulation—a phase of the reproductive cycle associated with increased sexual activity. A number of studies have linked testosterone rises in women to enhanced desire, erotic activity, intimatedaring, and sexual gratification. The pharmaceutical industry is closely studying the hormone in hopes of finding a blockbuster drug like Viagra that it can sell to women.
    Udupa’s research got little attention not only because it was done in faraway India. Science for many centuries has been international in character, and back in the 1970s obscure articles could get quick attention if they revealed something bold and new. A factor that added to the disregard was the emergence of other studies that seemed to contradict Udupa’s testosterone findings. Thus, scientists aware of the work increasingly saw his conclusions as hollow. In short, the topic became muddled—a common problem in backwater fields of science that fail to get the kind of intense scrutiny that can rapidly clear up complicated topics.
    It was the low-testosterone findings that initially led me to conclude falsely that yoga had little to do with human sexuality.
    The inconspicuous challenge to Udupa’s findings grew out of an ambitious body of yoga research that sought to