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."
In contrast to strongman or powerlifting competitions, where physical strength is paramount, or to Olympic weightlifting, where the main point is equally split between strength and technique, bodybuilding competitions typically emphasize condition, size, and symmetry. Different organizations emphasize particular aspects of competition, and sometimes have different categories in which to compete.
According to Georg Feuerstein, Laya yoga (yoga of dissolution or merging) "makes meditative absorption (laya) its focus. The laya-yogin seeks to transcend all memory traces and sensory experiences by dissolving the microcosm, the mind, in the transcendental Self-Consciousness." There are various forms and techniques of Laya yoga, including listening to the "inner sound" (nada), practicing various mudras like Khechari mudra and Shambhavi mudra as well as techniques meant to awaken a spiritual energy in the body (kundalini).
Niyama (The five "observances"): Śauca (purity, clearness of mind, speech and body), Santosha (contentment, acceptance of others and of one's circumstances), Tapas (persistent meditation, perseverance, austerity), Svādhyāya (study of self, self-reflection, study of Vedas), and Ishvara-Pranidhana (contemplation of God/Supreme Being/True Self).
^ Werner writes, "The word Yoga appears here for the first time in its fully technical meaning, namely as a systematic training, and it already received a more or less clear formulation in some other middle Upanishads....Further process of the systematization of Yoga as a path to the ultimate mystic goal is obvious in subsequent Yoga Upanishads and the culmination of this endeavour is represented by Patanjali's codification of this path into a system of the eightfold Yoga."
The hymns in Book 2 of the Shvetashvatara Upanishad, another late first millennium BCE text, states a procedure in which the body is held in upright posture, the breath is restrained and mind is meditatively focussed, preferably inside a cave or a place that is simple, plain, of silence or gently flowing water, with no noises nor harsh winds.
The Gita consists of 18 chapters and 700 shlokas (verses), with each chapter named as a different yoga, thus delineating eighteen different yogas. Some scholars divide the Gita into three sections, with the first six chapters with 280 shlokas dealing with Karma yoga, the middle six containing 209 shlokas with Bhakti yoga, and the last six chapters with 211 shlokas as Jnana yoga; however, this is rough because elements of karma, bhakti and jnana are found in all chapters.
Generally, the context in which an individual lives is of great importance for both his health status and quality of their life It is increasingly recognized that health is maintained and improved not only through the advancement and application of health science, but also through the efforts and intelligent lifestyle choices of the individual and society. According to the World Health Organization, the main determinants of health include the social and economic environment, the physical environment and the person's individual characteristics and behaviors.