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. 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. 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. 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. 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."
Various yogic groups had become prominent in Punjab in the 15th and 16th century, when Sikhism was in its nascent stage. Compositions of Guru Nanak, the founder of Sikhism, describe many dialogues he had with Jogis, a Hindu community which practiced yoga. Guru Nanak rejected the austerities, rites and rituals connected with Hatha Yoga. He propounded the path of Sahaja yoga or Nama yoga (meditation on the name) instead. The Guru Granth Sahib states:
Systematic activities to prevent or cure health problems and promote good health in humans are undertaken by health care providers. Applications with regard to animal health are covered by the veterinary sciences. The term "healthy" is also widely used in the context of many types of non-living organizations and their impacts for the benefit of humans, such as in the sense of healthy communities, healthy cities or healthy environments. In addition to health care interventions and a person's surroundings, a number of other factors are known to influence the health status of individuals, including their background, lifestyle, and economic, social conditions and spirituality; these are referred to as "determinants of health." Studies have shown that high levels of stress can affect human health.
According to Zimmer, Yoga philosophy is reckoned to be part of the non-Vedic system, which also includes the Samkhya school of Hindu philosophy, Jainism and Buddhism: "[Jainism] does not derive from Brahman-Aryan sources, but reflects the cosmology and anthropology of a much older pre-Aryan upper class of northeastern India [Bihar] – being rooted in the same subsoil of archaic metaphysical speculation as Yoga, Sankhya, and Buddhism, the other non-Vedic Indian systems."[note 6]
The tantra yoga practices include asanas and breathing exercises. The Nyingma tradition practices Yantra yoga (Tib. "Trul khor"), a discipline that includes breath work (or pranayama), meditative contemplation and other exercises. In the Nyingma tradition, the path of meditation practice is divided into further stages, such as Kriya yoga, Upa yoga, Yoga yana, Mahā yoga, Anu yoga and Ati yoga. The Sarma traditions also include Kriya, Upa (called "Charya"), and Yoga, with the Anuttara yoga class substituting for Mahayoga and Atiyoga.
The origins of yoga are a matter of debate. There is no consensus on its chronology or specific origin other than that yoga developed in ancient India. Suggested origins are the Indus Valley Civilization (3300–1900 BCE) and pre-Vedic Eastern states of India, the Vedic period (1500–500 BCE), and the śramaṇa movement. According to Gavin Flood, continuities may exist between those various traditions:
In the early 11th century, the Persian scholar Al Biruni visited India, lived with Hindus for 16 years, and with their help translated several significant Sanskrit works into Arabic and Persian languages. One of these was Patanjali's Yogasutras. Al Biruni's translation preserved many of the core themes of Patañjali 's Yoga philosophy, but certain sutras and analytical commentaries were restated making it more consistent with Islamic monotheistic theology. Al Biruni's version of Yoga Sutras reached Persia and Arabian peninsula by about 1050 AD. Later, in the 16th century, the hath yoga text Amritakunda was translated into Arabic and then Persian. Yoga was, however, not accepted by mainstream Sunni and Shia Islam. Minority Islamic sects such as the mystic Sufi movement, particularly in South Asia, adopted Indian yoga practises, including postures and breath control. Muhammad Ghawth, a Shattari Sufi and one of the translators of yoga text in 16th century, drew controversy for his interest in yoga and was persecuted for his Sufi beliefs.
^ Andrew J. Nicholson (2013). Unifying Hinduism: Philosophy and Identity in Indian Intellectual History. Columbia University Press. p. 26. ISBN 978-0-231-14987-7., Quote: "From a historical perspective, the Brahmasutras are best understood as a group of sutras composed by multiple authors over the course of hundreds of years, most likely composed in its current form between 400 and 450 BCE."
In the last week leading up to a contest, bodybuilders usually decrease their consumption of water, sodium, and carbohydrates, the former two to alter how water is retained by the body and the latter to reduce glycogen in the muscle. The day before the show, water is removed from the diet, and diuretics may be introduced, while carbohydrate loading is undertaken to increase the size of the muscles through replenishment of their glycogen. The goal is to maximize leanness and increase the visibility of veins, or "vascularity". The muscular definition and vascularity are further enhanced immediately before appearing on stage by darkening the skin through tanning products and applying oils to the skin to increase shine. Some competitors will eat sugar-rich foods to increase the visibility of their veins. A final step, called "pumping", consists in performing exercises with light weights or other kinds of low resistance (for instance two athletes can "pump" each other by holding a towel and pulling in turn), just before the contest, to fill the muscles with blood and further increase their size and density.
1 Reference for 5%: Blackburn G. (1995). Effect of degree of weight loss on health benefits. Obesity Research 3: 211S-216S. Reference for 10%: NIH, NHLBI Obesity Education Initiative. Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. Available online: http://www.nhlbi.nih.gov/guidelines/obesity/ob_gdlns.pdf Cdc-pdf[PDF-1.25MB]External
The earliest references to hatha yoga are in Buddhist works dating from the eighth century. 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. Hatha yoga synthesizes elements of Patanjali's Yoga Sutras with posture and breathing exercises. It marks the development of asanas (plural) into the full body 'postures' now in popular usage and, along with its many modern variations, is the style that many people associate with the word yoga today.
^ Mangano, Kelsey M.; Sahni, Shivani; Kiel, Douglas P.; Tucker, Katherine L.; Dufour, Alyssa B.; Hannan, Marian T. (February 8, 2017). "Dietary protein is associated with musculoskeletal health independently of dietary pattern: the Framingham Third Generation Study". The American Journal of Clinical Nutrition. 105 (3): 714–722. doi:10.3945/ajcn.116.136762. PMC 5320406. PMID 28179224 – via ajcn.nutrition.org.
The general strategy adopted by most present-day competitive bodybuilders is to make muscle gains for most of the year (known as the "off-season") and, approximately 12–14 weeks from competition, lose a maximum of body fat (referred to as "cutting") while preserving as much muscular mass as possible. The bulking phase entails remaining in a net positive energy balance (calorie surplus). The amount of a surplus in which a person remains is based on the person's goals, as a bigger surplus and longer bulking phase will create more fat tissue. The surplus of calories relative to one's energy balance will ensure that muscles remain in a state of anabolism.
Organized interventions to improve health based on the principles and procedures developed through the health sciences are provided by practitioners trained in medicine, nursing, nutrition, pharmacy, social work, psychology, occupational therapy, physical therapy and other health care professions. Clinical practitioners focus mainly on the health of individuals, while public health practitioners consider the overall health of communities and populations. Workplace wellness programs are increasingly adopted by companies for their value in improving the health and well-being of their employees, as are school health services in order to improve the health and well-being of children.
^ 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."
In 2008 between US$33 billion and $55 billion was spent annually in the US on weight-loss products and services, including medical procedures and pharmaceuticals, with weight-loss centers taking between 6 and 12 percent of total annual expenditure. Over $1.6 billion a year was spent on weight-loss supplements. About 70 percent of Americans' dieting attempts are of a self-help nature.