Some bodybuilders use drugs such as anabolic steroids and precursor substances such as prohormones to increase muscle hypertrophy. Anabolic steroids cause hypertrophy of both types (I and II) of muscle fibers, likely caused by an increased synthesis of muscle proteins. They also provoke undesired side effects including hepatotoxicity, gynecomastia, acne, the early onset of male pattern baldness and a decline in the body's own testosterone production, which can cause testicular atrophy.[43][44][45] Other performance-enhancing substances used by competitive bodybuilders include human growth hormone (HGH).
The origins of yoga have been speculated to date back to pre-Vedic Indian traditions; it is mentioned in the Rigveda,[note 1] but most likely developed around the sixth and fifth centuries BCE, in ancient India's ascetic and śramaṇa movements.[8][note 2] The chronology of earliest texts describing yoga-practices is unclear, varyingly credited to Upanishads.[9] The Yoga Sutras of Patanjali date from the first half of the 1st millennium CE,[10][11] and gained prominence in the West in the 20th century.[12] Hatha yoga texts emerged sometimes between the 9th and 11th century with origins in tantra.[13][14]

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]

The Yoga Sutras are also influenced by the Sramana traditions of Buddhism and Jainism, and may represent a further Brahmanical attempt to adopt yoga from the Sramana traditions.[129] As noted by Larson, there are numerous parallels in the concepts in ancient Samkhya, Yoga and Abhidharma Buddhist schools of thought, particularly from 2nd century BCE to 1st century AD.[139] Patanjali's Yoga Sutras is a synthesis of these three traditions. From Samkhya, the Yoga Sutras adopt the "reflective discernment" (adhyavasaya) of prakrti and purusa (dualism), its metaphysical rationalism, as well its three epistemic methods of gaining reliable knowledge.[139] From Abhidharma Buddhism's idea of nirodhasamadhi, suggests Larson, Yoga Sutras adopt the pursuit of altered state of awareness, but unlike Buddhism's concept of no self nor soul, Yoga is physicalist and realist like Samkhya in believing that each individual has a self and soul.[139] The third concept Yoga Sutras synthesize into its philosophy is the ancient ascetic traditions of meditation and introspection, as well as the yoga ideas from middle Upanishads such as Katha, Shvetashvatara and Maitri.[139]


According to Pāṇini, the term yoga can be derived from either of two roots, yujir yoga (to yoke) or yuj samādhau ("to concentrate").[27] In the context of the Yoga Sutras of Patanjali, the root yuj samādhau (to concentrate) is considered by traditional commentators as the correct etymology.[28] In accordance with Pāṇini, Vyasa who wrote the first commentary on the Yoga Sutras,[29] states that yoga means samādhi (concentration).[30]
Prolonged psychological stress may negatively impact health, and has been cited as a factor in cognitive impairment with aging, depressive illness, and expression of disease.[61] Stress management is the application of methods to either reduce stress or increase tolerance to stress. Relaxation techniques are physical methods used to relieve stress. Psychological methods include cognitive therapy, meditation, and positive thinking, which work by reducing response to stress. Improving relevant skills, such as problem solving and time management skills, reduces uncertainty and builds confidence, which also reduces the reaction to stress-causing situations where those skills are applicable.
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]
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