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Yoga and Medicine: What Med Students Should Know About this Ancient Health Practice


Why should future physicians know about yoga?

Yoga is an ancient health science based on the experimental and experiential. The physical postures and meditative practices of yoga developed through thousands of years of intent study of the body’s responses to particular postures and meditations. Many patients have already caught on to yoga as a form of mental and physical self-care and preventive health. If we adequately understand yoga, we can seize an opportunity to encourage the healthy thoughts and behaviors that our patients gain through yoga and to build upon them.

What should future physicians know about yoga? 

First, yoga is more than just an exercise class at the gym. It began primarily as a spiritual practice that used physical movements to prepare the mind for meditation. Yoga means “union” or “yoking” in Sanskrit, which originally referred to the practice of seeking union between the self and the divine. Yoga was first mentioned in the Rig Veda, one of the four oldest sacred texts of Hinduism. The Rig Veda was written between 1800 and 1850 B.C. in the Indus Valley in modern-day India. Around 200 A.D., a man named Patanjali codified the practice and teachings of yoga in collection of aphorisms called the Yoga Sutras. The Yoga Sutras outline eight limbs of yoga. They include “asana” physical postures, and “pranayama” breathing techniques, as well as what we might think of as moral codes and observances such as non-harming, purity, contentment and self-study.

Second, modern yoga is not bound to any certain religion. 

Although Yoga and Hinduism share a common culture, language and roots in the Rig Veda, yoga does not come from Hinduism. In fact, yoga predates Hinduism. According to evidence from cave drawings, people were likely practicing early forms of yoga 5,000 years ago. However, as yoga developed along Eastern religions, its philosophies were adopted by Hinduism, Jainism and Buddhism. Today, yoga is practiced by people of all religious beliefs. Although yoga is not a religion, its philosophy echoes many themes of the world’s major religions. Like prayer or other spiritual practices, yoga can be used to worship or seek the divine in a way compatible with one’s personal religious beliefs. Yoga is also used by non-religious people who seek a better understanding of themselves. Other yogis simply seek yoga’s physical and mental health benefits. Today yoga has come to mean a practice of uniting mind, body and spirit as well as union with the divine.

A myriad of unique yoga styles exist today that differ in pace, physical intensity and philosophical emphasis. 

Since Patanjali, yogis of various religious or spiritual paths have added different texts and practices to of the canon of yoga doctrine, giving rise to a complex lineage. The five original branches of yoga are called Hatha, Raja, Jhana, Karma and Bahkti. Raja means “royal.” This is essentially yoga as it was defined by Patanjali’s Yoga Sutras. The goal is union with the divine and discovery of the true self. Jhana seeks the divine through contemplation and study of sacred texts. Karma yoga centers on the goals of selflessness and intentionality. Bhakti is a practice of loving devotion to the divine. While much of the yoga practiced in the U.S. incorporates aspects of Jhana, Karma and Bhakti, Hatha yoga is currently the system most widely practiced here. Hatha was popularized by Sri Tirumalai Krishnamacharya in Southern India in the 1930s. Hatha means “forceful,” which likely refers to forcing the body into the physical postures and breathing patterns of yoga in order to meditate. Hatha is also translated as “sun-moon,” referring to balance between effort and surrender both mentally and physically within each pose.

Yoga has continued to be a dynamic entity since its introduction into the U.S.

Yoga came to the United States in 1893 via lectures given to the Parliament of the World’s Religions at the World’s Columbian Exposition in Chicago. However, it was not until the 1960s that yoga became widely known to Americans. By that time, Hatha yoga was giving rise to its own offshoots. Several of these new forms were developed by Sri Tirumalai Krishnamacharya’s students, including Ashtanga-Vinyasa and Iyengar. Ashtanga Vinyasa yoga moves quickly through six very challenging sets of poses that include lots of inversions or holding the feet above the head, backbends, “heart-opening” or chest-stretching poses, and twisting. Iyengar focuses on safe alignment, holding longer poses and using props for alignment when needed. Anasura, which focuses on precision in poses, was a further offshoot of Iyengar.

The other major styles of Hatha yoga are Bikram, Kundalini, Kripalu, Viniyoga and Integral yoga.

Bikram yoga, which came about in the 1970s, consists of a series of 26 poses and two breathing exercises, traditionally done in a room heated to 105 degrees for 90 minutes. This style is currently very popular nationwide both at private yoga studios and health clubs. Kundalini yoga uses rapid movements, visualizations, chants and vigorous breathing. One of the central ideas of this practice is that by aligning the central line of energy that runs down the spine, one awakens a vast store of energy called kundalini that leads to spiritual awakening. Kripalu, Integral and Viniyoga are all forms of “gentle yoga” that focus on yoga as an individualized form of self-care. Yoga is a dynamic practice that has developed over centuries and continues to change even today.

What does one do in a yoga class?

A yoga class today in the U.S. typically includes holding certain postures that alternately stretch certain muscle groups while strengthening others. These asanas are categorized into backward-bending, forward-bending, inversion, lying, seated, standing, twisting and relaxation poses. Many poses are named after animals or images from nature. As yogis move in and out of these various poses, awareness of the breath is emphasized through controlled breathing techniques that either relax or energize the body. The breathing techniques are collectively called “pranayama.”  Ujjayi or “victorious breath” is the primary technique used in Hatha yoga. It involves deep inhalations and exhalations through the nose with the mouth closed and the epiglottis held in the back of the throat. The sound of “haaa,” or the Darth Vader sound, is created with each breath, providing a relaxing sound with a wave-like quality. Most yoga classes also include meditation either while flowing through positions or as a distinct start or end to class.

What are yoga’s benefits?

It is helpful to consider yoga both within the framework yogis themselves use and through the modern scientific perspective. Traditionally, yoga poses are meant to stimulate and regulate the body’s various glands by compression. For example, shoulder stand and fish pose are said to compress the thyroid gland and therefore supposedly regulate weight problems. Different poses are recommended for different emotional ailments and physical needs. For example, twisting poses are said to aid in digestion.

Interestingly, some of the principles ancient yogis discovered by experience can be explained by modern medical science. For example, twisting poses aid in digestion by increasing return of blood flow following compression of the bowels. Twists also move the cerebrospinal fluid, nourishing the central nervous system. Inversions — putting one’s legs above the head in head stand, hand stand or shoulder stand — are likely experienced as “cleansing” because they help return lymphatic and venous flow from the extremities back to the circulation, allowing toxins to be filtered by the liver and spleen. Inversions can also lower the blood pressure, slow the heart rate and decrease the respiratory rate because they affect the carotid sinus baroreceptors.

In “Yoga as Medicine,” Dr. Timothy McCall, a board-certified internist and editor of the Yoga Journal, lists 40 research-supported ways that yoga heals. Research indicates that yoga’s benefits include increased flexibility, improved range of motion, strengthening of muscles and improvement in balance. These effects help prevent joint injuries and falls and enhance endurance and coordination. Yoga’s breathing techniques combined with cardiovascular exercise actually improve lung function; studies show increased vital capacity and peak flow in individuals that regularly practice yoga. Yoga also improves posture, which makes more space for lung expansion. These two effects combined explain why yoga has been shown to decrease the need for medications in mild to moderate asthma. Furthermore, yoga teaches breathing through the nose instead of the mouth, which helps filter pollen and pollutants that set off asthma attacks. Avoiding mouth breathing may also improve snoring and sleep apnea.

Yoga is a powerful health tool because it treats the mind and the body together.

Like many forms of exercise, yoga strengthens bones, promotes weight loss, improves cardiovascular conditioning and increases oxygenation of the tissues. However, yoga also strengthens bones and wards off osteoporosis via neurohormonal pathways in the brain. Its relaxation effects are shown to reduce levels of the stress hormone cortisol, which normally decreases bone formation and increases bone resorption. In addition to burning calories, yoga also allows practitioners to address mental and emotional factors related to weight gain, such as bringing consciousness back to the body’s physical cues and thereby curbing emotional eating.

Conversely, yoga affects the mind through the physical movement of the body.

For instance, a challenging yoga practice that requires all one’s effort and attention can give relief to a brooding or anxious mind. Attention to physical sensations in the body can help a depressed person feel more alive while the physical effects of yoga simultaneously restore energy to the body. For the average person with a normal amount of worry, yoga can lessen stress by unearthing the overreactions of the mind through non-judgmental self-study. Challenging poses teach yogis to find balance between accepting discomfort and making adjustments — a positive message that applies both to the mind and the body. In some places, yoga is now being used successfully by mental health professionals in conjunction with psychotherapy. This is a particularly useful tool for victims of early childhood or preverbal traumas, because it allows patients to feel and express things physically that are difficult to express verbally. For these reasons, the University of Minnesota Center for Spirituality and Healing’s online medical student module on yoga suggested that yoga is “arguably the most comprehensive method of stress reduction ever developed.”

A whole host of medical reasoning supports the preventative mental health benefits of yoga for the average person.

First, yoga works by retuning the nervous system so that it is better able to respond to stress by shifting between activation of the parasympathetic and sympathetic nervous systems as needed. Yoga effectively induces the relaxation response via the hypothalamic-adrenal-pituitary axis. It lowers levels of the stress hormones cortisol and monoamine oxidase and increases serotonin, endorphin and encephalin levels which collectively improve mood. Yoga has also been shown to increase the frequency of brainwaves associated with relaxation and with unconscious memory, dreams and emotions. Not only can yoga induce parasypmathetic-mediated relaxation but it also includes techniques like back bends and certain pranayama breathing exercises that stimulate the sympathetic nervous system, perhaps toning its response.

Overall, yoga causes the body to produce fewer catecholamines by lowering limbic stimulation. There are many benefits to mitigating the stress response. First, this leads to increased immunity. Like other meditative practices, yoga has been shown to increase immune function in people with weakened immune responses and decreased overactivity of the immune system in people with autoimmune dysfunction. Brain imaging has also shown that meditation techniques like yoga actually decrease pain signals between the thalamus and the cerebral cortex. This is good news for patients with chronic back pain, rheumatoid arthritis and osteoarthritis, to name a few.

In conclusion:

Despite a growing body of research on yoga’s physical and mental health benefits, there are aspects of yoga — such as the emotional result of holding a particular pose — that may never be proven through the Western scientific research model. In the yogic philosophy, the valued way of “knowing” is through experience. People who practice yoga are not necessarily concerned with why yoga works for them; they simply feel good afterwards and continue to come back to the mat. Thus, the best way for medical students to learn about yoga’s benefits is to actually experience it for ourselves. Yoga is a fun, playful and wonderfully physical practice of mindfulness that strongly counteracts the stress of our demanding career path.

CONTRAINDICATIONS TO YOGA: There are a few contraindications to specific yoga poses your patients should know. People with unmedicated hypertension, congestive heart failure, increased intracranial pressure, carotid artery stenosis, hiatal hernia, history of stroke, neck problems, glaucoma and detached retinas are advised not to do inversions because they raise pressure in the head and upper body. Traditionally, women who are menstruating are also taught not to do inversions because this disrupts the natural flow of menses out of body, and one theory explaining the development of endometriosis holds that retrograde blood flow through the Fallopian tubes might be the inciting factor. In general, one should refrain from a vigorous yoga practice when one feels sick, achy or has very low energy.

Jennie Barnes Jennie Barnes (1 Posts)

Contributing Writer Emeritus

Mayo Medical School

Jennie is a Class of 2015 Mayo Med student interested (so far) in OBGYN and family medicine. She grew up in Minneapolis, Minnesota and attended college at the University of North Carolina in Chapel Hill (go Tarheels!) where she studied women's health, medical anthropology and Spanish. When not in class or clinic, Jennie likes to practice yoga, run, bike, and generally just be outside, experiment with new recipes, throw dinner parties, and spend time with her husband-to-be. Fun facts: Jennie was also a competitive figure skater and a birth doula before med school.