Site enhancement oil, often called "santol" or "synthol" (no relation to the Synthol mouthwash brand), refers to oils injected into muscles to increase the size or change the shape. Some bodybuilders, particularly at the professional level, inject their muscles with such mixtures to mimic the appearance of developed muscle where it may otherwise be disproportionate or lacking.[55] This is known as "fluffing".[56][57] Synthol is 85% oil, 7.5% lidocaine, and 7.5% alcohol.[56] It is not restricted, and many brands are available on the Internet.[58] The use of injected oil to enhance muscle appearance is common among bodybuilders,[59][60] despite the fact that synthol can cause pulmonary embolisms, nerve damage, infections, sclerosing lipogranuloma,[61] stroke,[56] and the formation of oil-filled granulomas, cysts or ulcers in the muscle.[60][62][63] Rare cases might require surgical intervention to avoid further damage to the muscle and/or to prevent loss of life.[64]
Personal health also depends partially on the social structure of a person's life. The maintenance of strong social relationships, volunteering, and other social activities have been linked to positive mental health and also increased longevity. One American study among seniors over age 70, found that frequent volunteering was associated with reduced risk of dying compared with older persons who did not volunteer, regardless of physical health status.[59] Another study from Singapore reported that volunteering retirees had significantly better cognitive performance scores, fewer depressive symptoms, and better mental well-being and life satisfaction than non-volunteering retirees.[60]
According to Crangle, some researchers have favoured a linear theory, which attempts "to interpret the origin and early development of Indian contemplative practices as a sequential growth from an Aryan genesis",[53][note 4] just like traditional Hinduism regards the Vedas to be the ultimate source of all spiritual knowledge.[55][note 5] Thomas McEvilley favors a composite model where pre-Aryan yoga prototype existed in the pre-Vedic period and its refinement began in the Vedic period.[58]
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]
Malaysia's top Islamic body in 2008 passed a fatwa, prohibiting Muslims from practicing yoga, saying it had elements of Hinduism and that its practice was blasphemy, therefore haraam.[298] Some Muslims in Malaysia who had been practicing yoga for years, criticized the decision as "insulting."[299] Sisters in Islam, a women's rights group in Malaysia, also expressed disappointment and said yoga was just a form of exercise.[300] This fatwa is legally enforceable.[301] However, Malaysia's prime minister clarified that yoga as physical exercise is permissible, but the chanting of religious mantras is prohibited.[302]
Overtraining occurs when a bodybuilder has trained to the point where his workload exceeds his recovery capacity. There are many reasons why overtraining occurs, including lack of adequate nutrition, lack of recovery time between workouts, insufficient sleep, and training at a high intensity for too long (a lack of splitting apart workouts). Training at a high intensity too frequently also stimulates the central nervous system (CNS) and can result in a hyperadrenergic state that interferes with sleep patterns.[52] To avoid overtraining, intense frequent training must be met with at least an equal amount of purposeful recovery. Timely provision of carbohydrates, proteins, and various micronutrients such as vitamins, minerals, phytochemicals, even nutritional supplements are acutely critical. A mental disorder, informally called “bigorexia” (by analogy with anorexia), may account for overtraining in some individuals. Sufferers feel as if they are never big enough or muscular enough, which forces them to overtrain in order to try and reach their goal physique.[53]

Description of an early form of yoga called nirodhayoga (yoga of cessation) is contained in the Mokshadharma section of the 12th chapter (Shanti Parva) of the Mahabharata (third century BCE).[109] Nirodhayoga emphasizes progressive withdrawal from the contents of empirical consciousness such as thoughts, sensations etc. until purusha (Self) is realized. Terms like vichara (subtle reflection), viveka (discrimination) and others which are similar to Patanjali's terminology are mentioned, but not described.[110] There is no uniform goal of yoga mentioned in the Mahabharata. Separation of self from matter, perceiving Brahman everywhere, entering into Brahman etc. are all described as goals of yoga. Samkhya and yoga are conflated together and some verses describe them as being identical.[111] Mokshadharma also describes an early practice of elemental meditation.[112] Mahabharata defines the purpose of yoga as the experience of uniting the individual ātman with the universal Brahman that pervades all things.[111]

The first known appearance of the word "yoga", with the same meaning as the modern term, is in the Katha Upanishad,[9][95] probably composed between the fifth and third century BCE,[96][97] where it is defined as the steady control of the senses, which along with cessation of mental activity, leading to a supreme state.[67][note 13] Katha Upanishad integrates the monism of early Upanishads with concepts of samkhya and yoga. It defines various levels of existence according to their proximity to the innermost being Ātman. Yoga is therefore seen as a process of interiorization or ascent of consciousness.[99][100] It is the earliest literary work that highlights the fundamentals of yoga. White states:
The earliest references to hatha yoga are in Buddhist works dating from the eighth century.[200] The earliest definition of hatha yoga is found in the 11th century Buddhist text Vimalaprabha, which defines it in relation to the center channel, bindu etc.[201] Hatha yoga synthesizes elements of Patanjali's Yoga Sutras with posture and breathing exercises.[202] It marks the development of asanas (plural) into the full body 'postures' now in popular usage[186] and, along with its many modern variations, is the style that many people associate with the word yoga today.[203]
Sleep is an essential component to maintaining health. In children, sleep is also vital for growth and development. Ongoing sleep deprivation has been linked to an increased risk for some chronic health problems. In addition, sleep deprivation has been shown to correlate with both increased susceptibility to illness and slower recovery times from illness.[48] In one study, people with chronic insufficient sleep, set as six hours of sleep a night or less, were found to be four times more likely to catch a cold compared to those who reported sleeping for seven hours or more a night.[49] Due to the role of sleep in regulating metabolism, insufficient sleep may also play a role in weight gain or, conversely, in impeding weight loss.[50] Additionally, in 2007, the International Agency for Research on Cancer, which is the cancer research agency for the World Health Organization, declared that "shiftwork that involves circadian disruption is probably carcinogenic to humans," speaking to the dangers of long-term nighttime work due to its intrusion on sleep.[51] In 2015, the National Sleep Foundation released updated recommendations for sleep duration requirements based on age and concluded that "Individuals who habitually sleep outside the normal range may be exhibiting signs or symptoms of serious health problems or, if done volitionally, may be compromising their health and well-being."[52]
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]