As always, seek professional advice before using any of the methods listed.
Yoga is an umbrella term that includes religion, philosophy, and physical practices.
Whether yoga qualifies as an Alternative Medicine or not is debatable, although there are many that would believe it to be effective in the general raising of the practitioner's overall wellbeing.
Yoga - (joʊɡə/; Sanskrit: योग) is a physical, mental, and spiritual practice/discipline that originated out of India.
A bit of History
There is a broad variety of schools, practices and goals in Hinduism, Buddhism (including Vajrayana and Tibetan Buddhism and Jainism). The best-known would be Hatha yoga and Raja yoga.
There is speculation over the origins of Yoga, and some believe it to date back to pre-Vedic Indian traditions, but most likely developed around the sixth and fifth centuries BC, in ancient India's ascetic circles, which are also credited with the early sramana movements.
Some of the chronology of the earliest texts that describe the practices of yoga is not clear, sone credit it to the Hindu Upanishads, and others to the Buddhist Pāli Canon. The Yoga Sutras of Patanjali date from the first half of the 1st millennium CE, but it's prominence only really kicked off during the 20th century. Hatha yoga texts came to light around 11th century CE, and in its origins was related to Tantrism.
Yoga gurus from India later introduced yoga to western civilisation, after the success of Swami Vivekananda around the late 19th/early 20th century.
On to the '80s, and yoga became popular as a system of physical exercise all over the Western world. Yoga in Indian traditions, however, is more than just a physical exercise, it is linked to 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 the Hindu Samkhya philosophy.
A number of studies have tried to figure out 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.
In Vedic Sanskrit, the more commonly used, literal meaning of the word yoga is "to add", "to join", "to unite", or "to attach", from the root yuj, already had a much more figurative sense, where the yoking or harnessing of oxen or horses takes on broader meanings such as "employment, use, application, performance" (compare the figurative uses of "to harness" as in "to put something to some use"). All further developments of the sense of this word are post-Vedic. More prosaic moods such as "exertion", "endeavour", "zeal", and "diligence" are also found in Epic Sanskrit.
There are very many compound words containing yog in Sanskrit. Yoga can take on meanings such as "connection", "contact", "union", "method", "application", "addition" and "performance". In simpler words, Yoga also means "combined". For example, guṇá-yoga means "contact with a cord"; chakrá-yoga has a medical sense of "applying a splint or similar instrument by means of pulleys (in case of dislocation of the thigh)"; chandrá-yoga has the astronomical sense of "conjunction of the moon with a constellation"; puṃ-yoga is a grammatical term expressing "connection or relation with a man", etc. Thus, bhakti-yoga means "devoted attachment" in the monotheistic Bhakti movement. The term kriyā-yoga has a grammatical sense, meaning "connection with a verb". But the same compound is also given a technical meaning in the Yoga Sutras (2.1), designating the "practical" aspects of the philosophy, i.e. the "union with the Supreme" due to performance of duties in everyday life.
According to Pāṇini, a 6th-century BC Sanskrit grammarian, the term yoga can be derived from either of two roots, yujir yoga (to yoke) or yuj samādhau (to concentrate). In the context of the Yoga Sutras of Patanjali, the root yuj samādhau (to concentrate) is considered by traditional commentators as the correct etymology. In accordance with Pāṇini, Vyasa who wrote the first commentary on the Yoga Sutras, states that yoga means samādhi (concentration).
According to Dasgupta, the term yoga can be derived from either of two roots, yujir yoga (to yoke) or yuj samādhau (to concentrate). Someone who practices yoga or follows the yoga philosophy with a high level of commitment is called a yogi (may be applied to a male or a female) or yogini (traditionally denoting a female).
International Day of Yoga
On December the 11th, 2014, The United Nations General Assembly approved by consensus, establishing June the 21st as 'International Day of Yoga'. The declaration of this day came after the call for the adoption of 21 June as International Day of Yoga by Indian Prime Minister Narendra Modi during his address to UN General Assembly on September the 27th, 2014. In suggesting June 21, which is the Summer Solstice, as the International Day of Yoga, Narendra Modi had said that the date is the longest day of the year in the Northern Hemisphere and has special significance in many parts of the world.
The first international day of Yoga was observed world over on June the 21st, 2015. About 35000 people, including the Indian Prime Minister, as well as a large number of dignitaries, performed 21 Yoga asanas (yoga postures) for 35 minutes at Rajpath in New Delhi. The day devoted to Yoga was also observed by millions worldwide. The event at Rajpath, also established two Guinness records, 1) largest Yoga Class with 35985 people, 2) the record for the most nationalities participating in it, eighty four.