Pre-philosophical speculations of yoga begin to emerge in the texts of c. 500 – c. 200 BCE. Between 200 BCE and 500 CE, philosophical schools of Hinduism, Buddhism, and Jainism were taking form and a coherent philosophical system of yoga began to emerge.[50] The Middle Ages saw the development of many satellite traditions of yoga. Yoga came to the attention of an educated western public in the mid 19th century along with other topics of Indian philosophy.
Since the late 1970s, the federal Healthy People Initiative has been a visible component of the United States’ approach to improving population health.[11][12] In each decade, a new version of Healthy People is issued,[13] featuring updated goals and identifying topic areas and quantifiable objectives for health improvement during the succeeding ten years, with assessment at that point of progress or lack thereof. Progress has been limited to many objectives, leading to concerns about the effectiveness of Healthy People in shaping outcomes in the context of a decentralized and uncoordinated US health system. Healthy People 2020 gives more prominence to health promotion and preventive approaches and adds a substantive focus on the importance of addressing social determinants of health. A new expanded digital interface facilitates use and dissemination rather than bulky printed books as produced in the past. The impact of these changes to Healthy People will be determined in the coming years.[14]
^ On the dates of the Pali canon, Gregory Schopen writes, "We know, and have known for some time, that the Pali canon as we have it — and it is generally conceded to be our oldest source — cannot be taken back further than the last quarter of the first century BCE, the date of the Alu-vihara redaction, the earliest redaction we can have some knowledge of, and that — for a critical history — it can serve, at the very most, only as a source for the Buddhism of this period. But we also know that even this is problematic... In fact, it is not until the time of the commentaries of Buddhaghosa, Dhammapala, and others — that is to say, the fifth to sixth centuries CE — that we can know anything definite about the actual contents of [the Pali] canon."[92]
Some popular beliefs attached to weight loss have been shown to either have less effect on weight loss than commonly believed or are actively unhealthy. According to Harvard Health, the idea of metabolism being the "key to weight" is "part truth and part myth" as while metabolism does affect weight loss, external forces such as diet and exercise have an equal effect.[43] They also commented that the idea of changing one's rate of metabolism is under debate.[43] Diet plans in fitness magazines are also often believed to be effective, but may actually be harmful by limiting the daily intake of important calories and nutrients which can be detrimental depending on the person and are even capable of driving individuals away from weight loss.[44]
Similarly, Brahma sutras – the foundational text of the Vedanta school of Hinduism, discusses yoga in its sutra 2.1.3, 2.1.223 and others.[121] Brahma sutras are estimated to have been complete in the surviving form sometime between 450 BCE to 200 CE,[122][123] and its sutras assert that yoga is a means to gain "subtlety of body" and other powers.[121] The Nyaya sutras – the foundational text of the Nyaya school, variously estimated to have been composed between the 6th-century BCE and 2nd-century CE,[124][125] discusses yoga in sutras 4.2.38–50. This ancient text of the Nyaya school includes a discussion of yogic ethics, dhyana (meditation), samadhi, and among other things remarks that debate and philosophy is a form of yoga.[126][127][128]
Yogaśataka a Jain work by Haribhadra Suri 6th century CE "With conviction, the lords of Yogins have in our doctrine defined yoga as the concurrence (sambandhah) of the three [correct knowledge (sajjñana), correct doctrine (saddarsana) and correct conduct (saccaritra)] beginning with correct knowledge, since [thereby arises] conjunction with liberation....In common usage this [term] yoga also [denotes the soul’s] contact with the causes of these [three], due to the common usage of the cause for the effect. (2, 4).[32]
The earliest extant systematic account of yoga and a bridge from the earlier Vedic uses of the term is found in the Hindu Katha Upanisad (Ku), a scripture dating from about the third century BCE[…] [I]t describes the hierarchy of mind-body constituents—the senses, mind, intellect, etc.—that comprise the foundational categories of Sāmkhya philosophy, whose metaphysical system grounds the yoga of the Yogasutras, Bhagavad Gita, and other texts and schools (Ku3.10–11; 6.7–8).[101]
^ The Pāli and Sanskrit word bhāvanā literally means "development" as in "mental development." For the association of this term with "meditation," see Epstein (1995), p. 105; and, Fischer-Schreiber et al. (1991), p. 20. As an example from a well-known discourse of the Pali Canon, in "The Greater Exhortation to Rahula" (Maha-Rahulovada Sutta, MN 62), Ven. Sariputta tells Ven. Rahula (in Pali, based on VRI, n.d.): ānāpānassatiṃ, rāhula, bhāvanaṃ bhāvehi. Thanissaro (2006) translates this as: "Rahula, develop the meditation [bhāvana] of mindfulness of in-&-out breathing." (Square-bracketed Pali word included based on Thanissaro, 2006, end note.)
The Yoga Yajnavalkya is a classical treatise on yoga attributed to the Vedic sage Yajnavalkya. It takes the form of a dialogue between Yajnavalkya and Gargi, a renowned philosopher.[162] The text contains 12 chapters and its origin has been traced to the period between the second century BCE and fourth century CE.[163] Many yoga texts like the Hatha Yoga Pradipika, the Yoga Kundalini and the Yoga Tattva Upanishads have borrowed verses from or make frequent references to the Yoga Yajnavalkya.[164] The Yoga Yajnavalkya discusses eight yoga Asanas – Swastika, Gomukha, Padma, Vira, Simha, Bhadra, Mukta and Mayura,[165] numerous breathing exercises for body cleansing,[166] and meditation.[167]

Mental illness is described as 'the spectrum of cognitive, emotional, and behavioral conditions that interfere with social and emotional well-being and the lives and productivity of people. Having a mental illness can seriously impair, temporarily or permanently, the mental functioning of a person. Other terms include: 'mental health problem', 'illness', 'disorder', 'dysfunction'.[37]
Core: Yes. There are yoga poses to target just about every core muscle. Want to tighten those love handles? Then prop yourself up on one arm and do a side plank. To really burn out the middle of your abs, you can do boat pose, in which you balance on your "sit bones" (the bony prominences at the base of your pelvic bones) and hold your legs up in the air.
These meditations were seen as being supported by the other elements of the eightfold path, such as the practice of ethics, right exertion, sense restraint and right view.[244] Two mental qualities are said to be indispensable for yogic practice in Buddhism, samatha (calm, stability) and vipassanā (insight, clear seeing).[245] Samatha is the quality of a stable, relaxed and calm mind. It is also associated with samadhi (mental unification, focus) and dhyana (a state of meditative absorption). Vipassanā meanwhile, is a kind of insight or penetrative understanding into the true nature of phenomena. It is also defined as "seeing things as they truly are" (yathābhūtaṃ darśanam). The true nature of things is defined and explained in different ways, but an important and unique feature of classical Buddhism is its understanding of all phenomena (dhammas) as being empty of a self (atman) or inherent essence, a doctrine termed Anatta ("not-self") and Śūnyatā (emptiness).[246][247] This is in sharp contrast with most other Indian traditions, whose goals are founded either on the idea of an individual soul (atman, jiva, purusha) or a universal monistic consciousness ( Brahman). Vipassanā also requires an understanding of suffering or dukkha (and thus the four noble truths), impermanence (anicca) and interdependent origination.