Yoga has been practiced in India for thousands of years; however, the modern practice of postures that we know as yoga is less than 100 years old. Yoga once consisted of breathing exercises (pranayamas) and meditation, spiritually grounded in Hindu and Buddhist philosophy such as non-violence and loving kindness. Postures were developed in the 20th century. Some yoga teachers believe that the physical exercise was created to help Western practitioners sit in meditation because achieving stillness for Westerners may be predicated on a certain degree of physical exhaustion. In India, practitioners follow a number of teachers whose differences are often philosophical, while in the West, schools of yoga often have different approaches to the physical practice: different series of postures (Bikram), the use of props and attention to alignment (Iynegar), the temperature of the studio (hot yoga), a dependence on an aerobic and strenuous series of linked postures (Ashtanga), and a seemingly endless series of variations representing fusions of Eastern and Western exercises, such as acroyoga and yoga with weights. However, the core practice generally consists of breathing exercises, physical postures (asanas) and seated meditation.
Yoga teachers and practitioners always touted the physical and mental health benefits of yoga practice. For many years these claims were accepted as true by believers and doubted as unlikely by non-believers, as if yoga were a religion that required faith for benefit to accrue. Only in the last two decades have researchers applied Western scientific empirical approaches to yoga in an attempt to investigate some of the health benefits. Some of the first work was performed in India and published in their medical journals. In 1999, the National Institute of Health, which funds a large body of academic medical research in the United States, established the National Center for Complementary and Alternative Medicine to support research on yoga and other medical practices, such as acupuncture, herbal medicine, mindfulness, meditation and massage therapy. The Western medical literature now contains several hundred studies examining the effectiveness of yoga as a treatment. The results have been very impressive and uphold the beliefs of yogis.
Yoga has been shown to be an effective treatment for many physical and mental disorders. There are randomized controlled trials (the benchmark of Western empirical scientific proof) demonstrating that yoga improves symptoms in patients with depression, post-traumatic stress disorder, anxiety, chronic pain syndromes, insomnia, schizophrenia and ADHD. Yoga improves breathing in patients with asthma and chronic obstructive pulmonary disease. It decreases episodes of abnormal heart rhythms such as paroxysmal atrial fibrillation. As an exercise, sun salutations, a basic series of linked, rhythmic yoga postures, has been shown to improve endurance, body muscle composition and strength.
Yoga also has been effective in addressing metabolic syndrome, which leads to adult onset diabetes, increased blood lipids or fats, high blood pressure and increased risk of heart attack and stroke. Sedentary adults enrolled in a yoga program were more likely to participate and to continue with yoga after the program was over than adults enrolled in a regular exercise program. Elders enrolled in yoga showed improved strength, balance and muscle tone with an improvement in mood and mental functioning. Yoga decreases stress in adults caring for elders with dementia and decreases performance anxiety and stress in adolescent musicians. Yoga has been shown to decrease symptoms in patients with lower back pain and to decrease pain and improve functioning in patients with carpal tunnel syndrome, a painful disorder of the wrists often associated with repetitive motion stress. Yoga has been effective in quitting smoking programs and in treating drug addiction. Yoga has been shown to decrease depression and improve mood in prenatal women and in patients with cancer. It decreases stress and depression in college students. Yoga has been used successfully to help children with asthma, anxiety and depression, obesity, and cancer.
Recently, advancing brain imaging technology allowed researchers to investigate the bigger question, “How does yoga really work?” Magnetic spectroscopy of the brain has revealed that yoga practice leads to increased vagus nerve tone and increased gamma-aminobutyric acid levels in the thalamus area of the brain. The vagus nerve, the so-called wandering tenth cranial nerve, supplies fibers to the brain and many organs in the body including the heart, lungs, intestines and pancreas. It may very well be that the increases in circulating prana, or yogic energy, touted by yogis is not an increase in mystical energy, but rather a measurable neurochemical event.
It seems like yoga is a universal cure-all, good for every medical problem. No matter what the patient has, just prescribe yoga and expect a miraculous recovery. Unfortunately, this is not true. It is important to step back to regain perspective on all this science. Yoga can decrease symptoms like pain, stress, tension and anxiety. It will increase fitness, endurance, strength and aerobic and anaerobic capacity. It will not cure or even prevent most diseases. It is a preventative strategy or an adjunct therapy that should be used to help maintain good health or to support mental and physical well-being in addition to specific treatments for particular diseases. For example, cardiac catheterization will relieve a blockage of the arteries supplying the heart. Yoga after this procedure may improve exercise ability, endurance and strength, and may help the patient with stress, depression and anxiety that often accompanies heart disease. Yoga, like all good medicine, is most effective when prescribed by a skilled teacher who is trusted by the patient, and if it is performed with proper technique, adherence to the prescription, follow-up, and appropriate expectations for benefit.