Yoga (//;Sanskrit, योग Listen) is a group of physical, mental, and spiritual practices or disciplines which originated in ancient India. There is a broad variety of Yoga schools, practices, and goals in Hinduism, Buddhism, and Jainism. Among the most well-known types of yoga are Hatha yoga and Rāja yoga.
The origins of yoga have been speculated to date back to pre-Vedic Indian traditions, it is mentioned in the Rigveda, but most likely developed around the sixth and fifth centuries BCE, in ancient India's ascetic and śramaṇa movements. The chronology of earliest texts describing yoga-practices is unclear, varyingly credited to Hindu Upanishads and Buddhist Pāli Canon,probably of third century BCE or later. The Yoga Sutras of Patanjali date from the first half of the 1st millennium CE,but only gained prominence in the West in the 20th century. Hatha yoga texts emerged around the 11th century with origins in tantra.
Yoga gurus from India later introduced yoga to the west, following the success of Swami Vivekananda in the late 19th and early 20th century.In the 1980s, yoga became popular as a system of physical exercise across the Western world.Yoga in Indian traditions, however, is more than physical exercise, it has a meditative and spiritual core. One of the six major orthodox schools of Hinduism is also called Yoga, which has its own epistemology and metaphysics, and is closely related to Hindu Samkhya philosophy.
Many studies have tried to determine the effectiveness of yoga as a complementary intervention for cancer, schizophrenia, asthma, and heart disease. The results of these studies have been mixed and inconclusive, with cancer studies suggesting none to unclear effectiveness, and others suggesting yoga may reduce risk factors and aid in a patient's psychological healing process.
Potential benefits for adults
While much of the medical community regards the results of yoga research as significant, others point to many flaws which undermine results. Much of the research on yoga has taken the form of preliminary studies or clinical trials of low methodological quality, including small sample sizes, inadequate blinding, lack of randomization, and high risk of bias. Long-term yoga users in the United States have reported musculoskeletal and mental health improvements, as well as reduced symptoms of asthma in asthmatics. There is evidence to suggest that regular yoga practice increases brain GABA levels, and yoga has been shown to improve mood and anxiety more than some other metabolically-matched exercises, such as walking.
The three main focuses of Hatha yoga (exercise, breathing, and meditation) make it beneficial to those suffering from heart disease. Overall, studies of the effects of yoga on heart disease suggest that yoga may reduce high blood-pressure, improve symptoms of heart failure, enhance cardiac rehabilitation, and lower cardiovascular risk factors. For chronic low back pain, specialist Yoga for Healthy Lower Backs has been found 30% more beneficial than usual care alone in a UK clinical trial. Other smaller studies support this finding.
The Yoga for Healthy Lower Backs programme is the dominant treatment for society (both cheaper and more effective than usual care alone) due to 8.5 fewer days off work each year. A research group from Boston University School of Medicine also tested yoga's effects on lower-back pain. Over twelve weeks, one group of volunteers practiced yoga while the control group continued with standard treatment for back pain. The reported pain for yoga participants decreased by one third, while the standard treatment group had only a five percent drop. Yoga participants also had a drop of 80% in the use of pain medication.
There has been an emergence of studies investigating yoga as a complementary intervention for cancer patients. Yoga is used for treatment of cancer patients to decrease depression, insomnia, pain, and fatigue and to increase anxiety control.Mindfulness Based Stress Reduction (MBSR) programs include yoga as a mind-body technique to reduce stress. A study found that after seven weeks the group treated with yoga reported significantly less mood disturbance and reduced stress compared to the control group. Another study found that MBSR had showed positive effects on sleep anxiety, quality of life, and spiritual growth in cancer patients.
Yoga has also been studied as a treatment for schizophrenia. Some encouraging, but inconclusive, evidence suggests that yoga as a complementary treatment may help alleviate symptoms of schizophrenia and improve health-related quality of life.
Implementation of the Kundalini Yoga Lifestyle has shown to help substance abuse addicts increase their quality of life according to psychological questionnaires like the Behavior and Symptom Identification Scale and the Quality of Recovery Index.
Yoga has been shown in a study to have some cognitive functioning (executive functioning, including inhibitory control) acute benefit.
A 2016 systematic review and meta-analysis found no evidence that yoga was effective for metabolic syndrome.
Over time, an extended yoga physiology developed, especially within the tantric tradition and hatha yoga. It pictures humans as composed of three bodies or five sheaths which cover the atman. The three bodies are described within the Mandukya Upanishad, which adds a fourth state, turiya, while the five sheaths (pancha-kosas) are described in the Taittiriya Upanishad. They are often integrated:
- Sthula sarira, the Gross body, comprising the Annamaya Kosha
- Suksma sarira, the Subtle body, composed of;
- the Pranamaya Kosha (Vital breath or Energy),
- Manomaya Kosha (Mind)
- the Vijnanamaya Kosha (Intellect)
- Karana sarira, the Causal body, comprising the Anandamaya Kosha (Bliss)
Within the subtle body energy flows through the nadis or channels, and is concentrated within the chakras.
It is claimed that yoga can be an excellent training for children and adolescents, both as a form of physical exercise and for breathing, focus, mindfulness, and stress relief: many school districts have considered incorporating yoga into their P.E. programs. The Encinitas, California school district gained a San Diego Superior Court Judge's approval to use yoga in P.E., holding against the parents who claimed the practice was intrinsically religious and hence should not be part of a state funded program.