Yoga as exercise or alternative medicine

Yoga is an Indian physical, mental, and spiritual practice or discipline. There is a broad variety of schools, practices and goals in Hinduism, Buddhism (including Vajrayana and Tibetan Buddhism) and Jainism. The best-known are Hatha yoga and Raja yoga.

The origins of Yoga have been speculated to date back to pre-Vedic Indian traditions, but most likely developed around the sixth and fifth centuries BCE, in ancient India's ascetic circles, which are also credited with the early sramana 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 from first half of 1st millennium CE is one of a key surviving major texts on Yoga. Hatha yoga texts emerged around 11th century CE, and in its origins was related toTantrism.

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 Samkhyaphilosophy.

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.

The ultimate goal of Yoga is moksha (liberation) though the exact definition of what form this takes depends on the philosophical or theological system with which it is conjugated.

According to Jacobsen, "Yoga has five principal meanings:

1. Yoga as a disciplined method for attaining a goal;
2. Yoga as techniques of controlling the body and the mind;
3. Yoga as a name of one of the schools or systems of philosophy (darśana);
4. Yoga in connection with other words, such as "hatha-, mantra-, and laya-," referring to traditions specialising in particular techniques of yoga;
5. Yoga as the goal of Yoga practice."

According to David Gordon White, from the 5th century CE onward, the core principles of "yoga" were more or less in place, and variations of these principles developed in various forms over time:

1. Yoga as an analysis of perception and cognition; illustration of this principle is found in Hindu texts such as the Bhagavad Gita and Yogasutras, as well as a number of Buddhist Mahāyāna works;
2. Yoga as the rising and expansion of consciousness; these are discussed in sources such as Hinduism Epic Mahābhārata, Jainism Praśamaratiprakarana;
3. Yoga as a path to omniscience; examples are found in Hinduism Nyaya and Vaisesika school texts as well as Buddhism Mādhyamaka texts, but in different ways;
4. Yoga as a technique for entering into other bodies, generating multiple bodies, and the attainment of other supernatural accomplishments; these are described in Tantricliterature of Hinduism and Buddhism, as well as the Buddhist Sāmaññaphalasutta;

White clarifies that the last principle relates to legendary goals of "yogi practice", different from practical goals of "yoga practice," as they are viewed in South Asian thought and practice since the beginning of the Common Era, in the various Hindu, Buddhist, and Jain philosophical schools.

Yoga as exercise or alternative medicine is a modern phenomenon which has been influenced by the ancient Indian practice of hatha yoga. It involves holding stretches as a kind of low-impact physical exercise, and is often used for therapeutic purposes. Yoga in this sense often occurs in a class and may involve meditation, imagery, breath work and music.

Both the meditative and the exercise components of hatha yoga have been researched for both specific and non-specific health benefits. Hatha yoga has been studied as an intervention for many conditions, including back pain, stress, and depression. In general, it can help improve quality of life, but does not treat disease.

A survey released in December 2008 by the US National Center for Complementary and Alternative Medicine found that hatha yoga was the sixth most commonly used alternative therapy in the United States during 2007, with 6.1 percent of the population participating.

While much of the medical community views the results of Hatha Yoga research to be significant, others argue that there were many flaws that undermine results. Much of the research on Hatha Yoga has been in 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. As of 2011, evidence suggests that Hatha Yoga may be at least as effective at improving health outcomes as other forms of mild physical exercise when added to standard care. What is found most concerning regarding the legitimacy of Hatha Yoga as a method of healing is the current lack of specificity and standardization regarding the practice of Hatha Yoga. One recent study examined the difficulties of implementing Hatha Yoga-based therapies and methods of healing without any detailed, standardized and vetted descriptions of the asanas promoted as being beneficial for healing. This research calls for the creation of supported intervention practices that could be distributed and applied for use in clinical practice for patients.

Hatha Yoga and Specific Mental Health Conditions

• Anxiety and depression. A 2010 literature review of the research on the use of Hatha Yoga for treating depression said that preliminary research suggests that Hatha Yoga may be effective in the management of depression. Both the exercise and the mindfulness meditation components may be helpful. However the review cautioned that "Although results from these trials are encouraging, they should be viewed as very preliminary because the trials, as a group, suffered from substantial methodological limitations."
• Attention deficit hyperactivity disorder. No benefit.
• Dementia. There is some evidence that exercise programs may help people with dementia perform their daily activities.

Hatha Yoga and Specific Physical Health Conditions

• Back pain. There is evidence that Hatha Yoga may be effective in the management of chronic, but not acute, low back pain.The results of another study on the efficacy of Hatha Yoga therapy for chronic low back pain showed that at around 24 weeks the Hatha Yoga group had statistically significant reductions in functional disability, pain intensity, and depression compared to a standard 6-months medical treatment. It was also concluded from this study that there was a significant trend in the Hatha Yoga group decreasing their use of pain medication compared that of the control group.
• Blood pressure. Although some evidence exists to suggest Hatha Yoga might help people with high blood pressure, overall this evidence is too weak for any recommendation to be made, and little is known of the safety implications of such an approach.
• Cancer. Practice of Hatha Yoga may improve quality-of-life measures in cancer patients. It is unclear what aspect(s) may be beneficial or what populations should be targeted. Hatha Yoga practice as part of cancer treatment has also shown improvement in biomarkers such as TNF-alpha, Interleukin 6 and IL-1beta. Stronger effects onbiomarkers as well as quality-of-life measures is associated with more frequent Hatha Yoga practice.Hatha Yoga has no effect on the underlying disease.
• Epilepsy. No benefit.
• Menopause-related symptoms. No benefit.
• Pediatric conditions. A 2009 systematic review concludes that there is insufficient evidence to support the use of Hatha Yoga for any indication in the pediatric population. No adverse events were reported, and most trials were positive but of low methodological quality.
• Rheumatic disease. Only weak evidence exists to support the use of Hatha Yoga as a complementary therapy for helping people with rheumatic diseases, and little is known of the safety of such use.
• Sports Related Physical Health. Increasingly Hatha Yoga is used to train sports-persons and athletes, to maximize performance, improve conditioning, and minimize injury. Hatha Yoga is used extensively within British soccer to minimize injury, with Manchester United star Ryan Giggs one of the most high-profile players to publicly incorporate it in his training regime.