Oral hygiene

 Oral hygiene

Oral hygiene is the practice of keeping one's mouth clean and free of disease and other problems (e.g. bad breath) by regular brushing of the teeth (dental hygiene) and cleaning between the teeth. It is important that oral hygiene be carried out on a regular basis to enable prevention of dental disease and bad breath. The most common types of dental disease are tooth decay (cavities, dental caries) and gum diseases, including gingivitis, and periodontitis.

General guidelines for adults suggest brushing at least twice a day with a fluoridated toothpaste: brushing last thing at night and at least on one other occasion. Cleaning between the teeth is called interdental cleaning and is as important as tooth brushing.This is because a toothbrush cannot reach between the teeth and therefore only removes about 50% of plaque from the surface of the teeth. There are many tools to clean between the teeth, including floss, tape and interdental brushes; it is up to each individual to choose which tool they prefer to use.

Sometimes white or straight teeth are associated with oral hygiene. However, a hygienic mouth can have stained teeth or crooked teeth. To improve the appearance of their teeth, people may use tooth whitening treatments and orthodontics.

The importance of the role of the oral microbiome in dental health has been increasingly recognized. Data from human oral microbiology research shows that a commensal microflora can switch to an opportunistic pathogenic flora through complex changes in their environment. These changes are driven by the host rather than the bacteria. Archeological evidence of calcified dental plaque shows marked shifts in the oral microbiome towards a disease-associated microbiome with cariogenic bacteria becoming dominant during the Industrial Revolution. Modern oral microbiota are significantly less diverse than historic populations. Caries (Cavities), for example, have become a major endemic disease, affecting 60-90% of schoolchildren in industrialized countries. In contrast, dental caries and periodontal diseases were rare in pre-Neolithic and early hominins.

Mental health

 

Mental health

Mental health encompasses emotional, psychological, and social well-being. It influences cognition, perception, and behavior. It also determines how an individual handles stress, interpersonal relationships, and decision-making. Mental health includes subjective well-being, perceived self-efficacy, autonomy, competence, intergenerational dependence, and self-actualization of one's intellectual and emotional potential, among others.From the perspectives of positive psychology or holism, mental health may include an individual's ability to enjoy life and to create a balance between life activities and efforts to achieve psychological resilience. Cultural differences, subjective assessments, and competing professional theories all affect how one defines "mental health".Some early signs related to mental health problems are sleep irritation, lack of energy and thinking of harming yourself or others.

Mental disorders

Mental health, as defined by the Public Health Agency of Canada, is an individual’s capacity to feel, think, and act in ways to achieve a better quality of life while respecting the personal, social, and cultural boundaries.Impairment of any of these are risk factors for mental disorders, or mental illness which is a component of mental health. Mental disorders are defined as the health conditions that affect and alter cognitive functioning, emotional responses, and behavior associated with distress and/or impaired functioning.The ICD-11 is the global standard used to diagnose, treat, research, and report various mental disorders. In the United States, the DSM-5 is used as the classification system of mental disorders.

Mental health is associated with a number of lifestyle factors such as diet, exercise, stress, drug abuse, social connections and interactions. Therapists, psychiatrists, psychologists, social workers, nurse practitioners, or family physicians can help manage mental illness with treatments such as therapy, counseling or medication.

History

Early history

In the mid-19th century, William Sweetser was the first to coin the term mental hygiene, which can be seen as the precursor to contemporary approaches to work on promoting positive mental health. Isaac Ray, the fourth president of the American Psychiatric Association and one of its founders, further defined mental hygiene as "the art of preserving the mind against all incidents and influences calculated to deteriorate its qualities, impair its energies, or derange its movements".

In American history, mentally ill patients were thought to be religiously punished. This response persisted through the 1700s, along with inhumane confinement and stigmatization of such individuals. Dorothea Dix (1802–1887) was an important figure in the development of the "mental hygiene" movement. Dix was a school teacher who endeavored to help people with mental disorders and to expose the sub-standard conditions into which they were put. This became known as the "mental hygiene movement". Before this movement, it was not uncommon that people affected by mental illness would be considerably neglected, often left alone in deplorable conditions without sufficient clothing.From 1840 to 1880, she won over the support of the federal government to set up over 30 state psychiatric hospitals; however, they were understaffed, under-resourced, and were accused of violating human rights.

Emil Kraepelin in 1896 developed the taxonomy of mental disorders which has dominated the field for nearly 80 years. Later, the proposed disease model of abnormality was subjected to analysis and considered normality to be relative to the physical, geographical and cultural aspects of the defining group.

At the beginning of the 20th century, Clifford Beers founded "Mental Health America – National Committee for Mental Hygiene", after publication of his accounts as a patient in several lunatic asylums, A Mind That Found Itself, in 1908 and opened the first outpatient mental health clinic in the United States.

The mental hygiene movement, similar to the social hygiene movement, had at times been associated with advocating eugenics and sterilization of those considered too mentally deficient to be assisted into productive work and contented family life. In the post-WWII years, references to mental hygiene were gradually replaced by the term 'mental health' due to its positive aspect that evolves from the treatment of illness to preventive and promotive areas of healthcare.

Deinstitutionalization and transinstitutionalization

When state hospitals were accused of violating human rights, advocates pushed for deinstitutionalization: the replacement of federal mental hospitals for community mental health services. The closure of state-provisioned psychiatric hospitals was enforced by the Community Mental Health Centers Act in 1963 that laid out terms in which only patients who posed an imminent danger to others or themselves could be admitted into state facilities. This was seen as an improvement from previous conditions. However, there remains a debate on the conditions of these community resources.

It has been proven that this transition was beneficial for many patients: there was an increase in overall satisfaction, a better quality of life, more friendships between patients, and not too costly. This proved to be true only in the circumstance that treatment facilities that had enough funding for staff and equipment as well as proper management. However, this idea is a polarizing issue. Critics of deinstitutionalization argue that poor living conditions prevailed, patients were lonely, and they did not acquire proper medical care in these treatment homes. Additionally, patients that were moved from state psychiatric care to nursing and residential homes had deficits in crucial aspects of their treatment. Some cases result in the shift of care from health workers to patients’ families, where they do not have the proper funding or medical expertise to give proper care.On the other hand, patients that are treated in community mental health centers lack sufficient cancer testing, vaccinations, or otherwise regular medical check-ups.

Other critics of state deinstitutionalization argue that this was simply a transition to "transinstitutionalization", or the idea that prisons and state-provisioned hospitals are interdependent. In other words, patients become inmates. This draws on the Penrose Hypothesis of 1939, which theorized that there was an inverse relationship between prisons’ population size and the number of psychiatric hospital beds. This means that populations that require psychiatric mental care will transition between institutions, which in this case, includes state psychiatric hospitals and criminal justice systems. Thus, a decrease in available psychiatric hospital beds occurred at the same time as an increase in inmates. Although some are skeptical that this is due to other external factors, others will reason this conclusion to a lack of empathy for the mentally ill. There is no argument in the social stigmatization of those with mental illnesses, they have been widely marginalized and discriminated against in society. In this source, researchers analyze how most compensation prisoners (detainees who are unable or unwilling to pay a fine for petty crimes) are unemployed, homeless, and with an extraordinarily high degree of mental illnesses and substance use disorders. Compensation prisoners then lose prospective job opportunities, face social marginalization, and lack access to resocialization programs, which ultimately facilitate reoffending. The research sheds light on how the mentally ill—and in this case, the poor—are further punished for certain circumstances that are beyond their control, and that this is a vicious cycle that repeats itself. Thus, prisons embody another state-provisioned mental hospital.

Families of patients, advocates, and mental health professionals still call for the increase in more well-structured community facilities and treatment programs with a higher quality of long-term inpatient resources and care. With this more structured environment, the United States will continue with more access to mental health care and an increase in the overall treatment of the mentally ill.

However, there is still a lack of studies for mental health conditions (MHCs) to raise awareness, knowledge development, and attitude of seeking medical treatment for MHCs in Bangladesh. People in rural areas often seek treatment from the traditional healers and MHCs are sometimes considered a spiritual matter.

Walking

 

Walking

Computer simulation of a human walk cycle. In this model the head keeps the same level at all times, whereas the hip follows a sine curve.

Walking (also known as ambulation) is one of the main gaits of terrestrial locomotion among legged animals. Walking is typically slower than running and other gaits. Walking is defined by an 'inverted pendulum' gait in which the body vaults over the stiff limb or limbs with each step. This applies regardless of the usable number of limbs—even arthropods, with six, eight, or more limbs, walk.

The word walk is descended from the Old English wealcan "to roll". In humans and other bipeds, walking is generally distinguished from running in that only one foot at a time leaves contact with the ground and there is a period of double-support. In contrast, running begins when both feet are off the ground with each step. This distinction has the status of a formal requirement in competitive walking events. For quadrupedal species, there are numerous gaits which may be termed walking or running, and distinctions based upon the presence or absence of a suspended phase or the number of feet in contact any time do not yield mechanically correct classification. The most effective method to distinguish walking from running is to measure the height of a person's centre of mass using motion capture or a force plate at midstance. During walking, the centre of mass reaches a maximum height at midstance, while running, it is then at a minimum. This distinction, however, only holds true for locomotion over level or approximately level ground. For walking up grades above 10%, this distinction no longer holds for some individuals. Definitions based on the percentage of the stride during which a foot is in contact with the ground (averaged across all feet) of greater than 50% contact corresponds well with identification of 'inverted pendulum' mechanics and are indicative of walking for animals with any number of limbs, although this definition is incomplete. Running humans and animals may have contact periods greater than 50% of a gait cycle when rounding corners, running uphill or carrying loads.

Speed is another factor that distinguishes walking from running. Although walking speeds can vary greatly depending on many factors such as height, weight, age, terrain, surface, load, culture, effort, and fitness, the average human walking speed at crosswalks is about 5.0 kilometres per hour (km/h), or about 1.4 meters per second (m/s), or about 3.1 miles per hour (mph). Specific studies have found pedestrian walking speeds at crosswalks ranging from 4.51 to 4.75 km/h (2.80 to 2.95 mph) for older individuals and from 5.32 to 5.43 km/h (3.31 to 3.37 mph) for younger individuals;a brisk walking speed can be around 6.5 km/h (4.0 mph). In Japan, the standard measure for walking speed is 80 m/min (4.8 km/h). Champion racewalkers can average more than 14 km/h (8.7 mph) over a distance of 20 km (12 mi).

Health benefits

Main article: Physical exercise

Regular, brisk exercise of any kind can improve confidence, stamina, energy, weight control and life expectancy and reduces stress. It can also decrease the risk of coronary heart disease, strokes, diabetes, high blood pressure, bowel cancer and osteoporosis. Scientific studies have also shown that walking, besides its physical benefits, is also beneficial for the mind, improving memory skills, learning ability, concentration, mood, creativity, and abstract reasoning. Sustained walking sessions for a minimum period of thirty to sixty minutes a day, five days a week, with the correct walking posture, reduce health risks and have various overall health benefits, such as reducing the chances of cancer, type 2 diabetes, heart disease, anxiety disorder and depression. Life expectancy is also increased even for individuals suffering from obesity or high blood pressure. Walking also improves bone health, especially strengthening the hip bone, and lowering the harmful low-density lipoprotein (LDL) cholesterol, and raising the useful high-density lipoprotein (HDL) cholesterol. Studies have found that walking may also help prevent dementia and Alzheimer's.

The Centers for Disease Control and Prevention's fact sheet on the "Relationship of Walking to Mortality Among U.S. Adults with Diabetes" states that those with diabetes who walked for 2 or more hours a week lowered their mortality rate from all causes by 39 percent. Women who took 4,500 steps to 7,500 steps a day seemed to have fewer premature deaths compared to those who only took 2,700 steps a day. "Walking lengthened the life of people with diabetes regardless of age, sex, race, body mass index, length of time since diagnosis and presence of complications or functional limitations." It has been suggested that there is a relationship between the speed of walking and health, and that the best results are obtained with a speed of more than 2.5 mph (4 km/h).

Governments now recognize the benefits of walking for mental and physical health and are actively encouraging it. This growing emphasis on walking has arisen because people walk less nowadays than previously. In the UK, a Department of Transport report[14] found that between 1995/97 and 2005 the average number of walk trips per person fell by 16%, from 292 to 245 per year. Many professionals in local authorities and the National Health Service are employed to halt this decline by ensuring that the built environment allows people to walk and that there are walking opportunities available to them. Professionals working to encourage walking come mainly from six sectors: health, transport, environment, schools, sport and recreation, and urban design.

One program to encourage walking is "The Walking the Way to Health Initiative", organized by the British walkers association The Ramblers, which is the largest volunteer led walking scheme in the United Kingdom. Volunteers are trained to lead free Health Walks from community venues such as libraries and doctors' surgeries. The scheme has trained over 35,000 volunteers and has over 500 schemes operating across the UK, with thousands of people walking every week. A new organization called "Walk England" launched a web site in June 2008 to provide these professionals with evidence, advice, and examples of success stories of how to encourage communities to walk more. The site has a social networking aspect to allow professionals and the public to ask questions, post news and events, and communicate with others in their area about walking, as well as a "walk now" option to find out what walks are available in each region. Similar organizations exist in other countries and recently a "Walking Summit" was held in the United States. This "assembled thought-leaders and influencers from business, urban planning and real estate, [along with] physicians and public health officials", and others, to discuss how to make American cities and communities places where "people can and want to walk". Walking is more prevalent in European cities that have dense residential areas mixed with commercial areas and good public transportation.

Origins

File:Gait-of-healthy-Hamster.ogv

It is theorized that "walking" among tetrapods originated underwater with air-breathing fish that could "walk" underwater, giving rise (potentially with vertebrates like Tiktaalik) to the plethora of land-dwelling life that walk on four or two limbs. While terrestrial tetrapods are theorised to have a single origin, arthropods and their relatives are thought to have independently evolved walking several times, specifically in insects, myriapods, chelicerates, tardigrades, onychophorans, and crustaceans. Little skates, members of the demersal fish community, can propel themselves by pushing off the ocean floor with their pelvic fins, using neural mechanisms which evolved as early as 420 million years ago, before vertebrates set foot on land.

Hominin

Data in the fossil record indicate that among hominin ancestors, bipedal walking was one of the first defining characteristics to emerge, predating other defining characteristics of Hominidae  Judging from footprints discovered on a former shore in Kenya, it is thought possible that ancestors of modern humans were walking in ways very similar to the present activity as many as 3 million years ago.

Today, the walking gait of humans is unique and differs significantly from bipedal or quadrupedal walking gaits of other primates, like chimpanzees. It is believed to have been selectively advantageous in hominin ancestors in the Miocene due to metabolic energy efficiency. Human walking has been found to be slightly more energy efficient than travel for a quadrupedal mammal of a similar size, like chimpanzees. The energy efficiency of human locomotion can be accounted for by the reduced use of muscle in walking, due to an upright posture which places ground reaction forces at the hip and knee. When walking bipedally, chimpanzees take a crouched stance with bent knees and hips, forcing the quadricep muscles to perform extra work and consequently costs more energy. Comparing chimpanzee quadrupedal travel to that of true quadrupedal animals has indicated that chimpanzees expend one-hundred and fifty percent of the energy required for travel compared to true quadrupeds.

In 2007, a study further explored the origin of human bipedalism, using chimpanzee and human energetic costs of locomotion. They found that the energy spent in moving the human body is less than what would be expected for an animal of similar size and approximately seventy-five percent less costly than that of chimpanzees. Chimpanzee quadrupedal and bipedal energy costs are found to be relatively equal, with chimpanzee bipedalism costing roughly ten percent more than quadrupedal. The same 2007 study found that among chimpanzee individuals, the energy costs for bipedal and quadrupedal walking varied significantly, and those that flexed their knees and hips to a greater degree and took a more upright posture, closer to that of humans, were able to save more energy than chimpanzees that did not take this stance. Further, compared to other apes, humans have longer legs and short dorsally oriented ischia (hipbone), which result in longer hamstring extensor moments, improving walking energy economy. It was thought that hominins like Ardipithecus ramidus, which had a variety of both terrestrial and arboreal adaptions would not be as efficient walkers, however, with a small body mass A. ramidus had developed an energy efficient means of bipedal walking while still maintaining arboreal adaptations.  Humans have long femoral necks, meaning that while walking, hip muscles do not require as much energy to flex while moving. These slight kinematic and anatomic differences demonstrate how bipedal walking may have developed as the dominant means of locomotion among early hominins because of the energy saved. 

Variants

Nordic walkers

Scrambling is a method of ascending a hill or mountain that involves using both hands, because of the steepness of the terrain. Of necessity, it will be a slow and careful form of walking and with possibly of occasional brief, easy rock climbing. Some scrambling takes place on narrow exposed ridges where more attention to balance will be required than in normal walking.

Snow shoeing – A snowshoe is a footwear for walking over the snow. Snowshoes work by distributing the weight of the person over a larger area so that the person's foot does not sink completely into the snow, a quality called "flotation". It is often said by snowshoers that if you can walk, you can snowshoe. This is true in optimal conditions, but snowshoeing properly requires some slight adjustments to walking. The method of walking is to lift the shoes slightly and slide the inner edges over each other, thus avoiding the unnatural and fatiguing "straddle-gait" that would otherwise be necessary. A snowshoer must be willing to roll his or her feet slightly as well. An exaggerated stride works best when starting out, particularly with larger or traditional shoes.

Cross-country skiing – originally conceived like snow shoes as a means of travel in deep snow. Trails hiked in the summer are often skied in the winter and the Norwegian Trekking Association maintains over 400 huts stretching across thousands of kilometres of trails which hikers can use in the summer and skiers in the winter.

Beach walking is a sport that is based on a walk on the sand of the beach. Beach walking can be developed on compact sand or non-compact sand. There are beach walking competitions on non-compact sand, and there are world records of beach walking on non-compact sand in Multiday distances. Beach walking has a specific technique of walk.

Nordic walking is a physical activity and a sport, which is performed with specially designed walking poles similar to ski poles. Compared to regular walking, Nordic walking (also called pole walking) involves applying force to the poles with each stride. Nordic walkers use more of their entire body (with greater intensity) and receive fitness building stimulation not present in normal walking for the chest, lats, triceps, biceps, shoulder, abdominals, spinal and other core muscles that may result in significant increases in heart rate at a given pace. Nordic walking has been estimated as producing up to a 46% increase in energy consumption, compared to walking without poles.

Pedestrianism is a sport that developed during the late eighteenth and nineteenth centuries, and was a popular spectator sport in the British Isles. By the end of the 18th century, and especially with the growth of the popular press, feats of foot travel over great distances (similar to a modern ultramarathon) gained attention, and were labeled "pedestrianism". Interest in the sport, and the wagering which accompanied it, spread to the United States, Canada, and Australia in the 19th century. By the end of the 19th century, Pedestrianism was largely displaced by the rise in modern spectator sports and by controversy involving rules, which limited its appeal as a source of wagering and led to its inclusion in the amateur athletics movement. Pedestrianism was first codified in the last half of the 19th century, evolving into what would become racewalking, By the mid 19th century, competitors were often expected to extend their legs straight at least once in their stride, and obey what was called the "fair heel and toe" rule. This rule, the source of modern racewalking, was a vague commandment that the toe of one foot could not leave the ground before the heel of the next foot touched down. This said, rules were customary and changed with the competition. Racers were usually allowed to jog in order to fend off cramps, and it was distance, not code, which determined gait for longer races. Newspaper reports suggest that "trotting" was common in events.

Speed walking is the general term for fast walking. Within the Speed Walking category are a variety of fast walking techniques: Power Walking, Fit Walking, etc.

Power walking is the act of walking with a speed at the upper end of the natural range for walking gait, typically 7 to 9 km/h (4.5 to 5.5 mph). To qualify as power walking as opposed to jogging or running, at least one foot must be in contact with the ground at all times.

Racewalking is a long-distance athletic event. Although it is a foot race, it is different from running in that one foot must appear to be in contact with the ground at all times. Stride length is reduced, so to achieve competitive speeds, racewalkers must attain cadence rates comparable to those achieved by Olympic 800-meter runners, and they must do so for hours at a time since the Olympic events are the 20 km (12.4 mi) race walk (men and women) and 50 km (31 mi) race walk (men only), and 50-mile (80.5 km) events are also held. See also pedestrianism above.

Afghan walking: The Afghan Walk is a rhythmic breathing technique synchronized with walking. It was born in the 1980s on the basis of the observations made by the Frenchman Édouard G. Stiegler, during his contacts with Afghan caravaners, capable of making walks of more than 60 km per day for dozens of days.

Yoga

 

Yoga

Yoga is first mentioned in the Rigveda, and is referred to in a number of the Upanishads. The first known appearance of the word "yoga" with the same meaning as the modern term is in the Katha Upanishad, which was probably composed between the fifth and third centuries BCE. Yoga continued to develop as a systematic study and practice during the fifth and sixth centuries BCE in ancient India's ascetic and Śramaṇa movements. The most comprehensive text on Yoga, the Yoga Sutras of Patanjali, date to the early centuries of the Common Era; Yoga philosophy became known as one of the six orthodox philosophical schools (Darśanas) of Hinduism in the second half of the first millennium CE. Hatha yoga texts began to emerge between the ninth and 11th centuries, originating in tantra.

The term "yoga" in the Western world often denotes a modern form of Hatha yoga and a posture-based physical fitness, stress-relief and relaxation technique, consisting largely of the asanas; this differs from traditional yoga, which focuses on meditation and release from worldly attachments. It was introduced by gurus from India after the success of Swami Vivekananda's adaptation of yoga without asanas in the late 19th and early 20th centuries. Vivekananda introduced the Yoga Sutras to the West, and they became prominent after the 20th-century success of hatha yoga.

Etymology

Outdoor statue

The Sanskrit noun योग yoga is derived from the root yuj (युज्) "to attach, join, harness, yoke". Yoga is a cognate of the English word "yoke".[28] According to Mikel Burley, the first use of the root of the word "yoga" is in hymn 5.81.1 of the Rigveda, a dedication to the rising Sun-god, where it has been interpreted as "yoke" or "control."

Pāṇini (4th c. BCE) wrote that the term yoga can be derived from either of two roots: yujir yoga (to yoke) or yuj samādhau ("to concentrate").[32] In the context of the Yoga Sutras, the root yuj samādhau (to concentrate) is considered the correct etymology by traditional commentators.

In accordance with Pāṇini, Vyasa (who wrote the first commentary on the Yoga Sutras) says that yoga means samadhi (concentration).[35] In the Yoga Sutras (2.1), kriyāyoga is yoga's "practical" aspect: the "union with the supreme" in the performance of everyday duties. A person who practices yoga, or follows the yoga philosophy with a high level of commitment, is called a yogi; a female yogi may also be known as a yogini.

Definition in classical texts

The term yoga has been defined in a number of ways in Indian philosophical and religious traditions.

Definition of Yoga

Vaisesika sutra c. 4th century BCE "Pleasure and suffering arise as a result of the drawing together of the sense organs, the mind and objects. When that does not happen because the mind is in the self, there is no pleasure or suffering for one who is embodied. That is yoga" 

Katha Upanishad last centuries BCE "When the five senses, along with the mind, remain still and the intellect is not active, that is known as the highest state. They consider yoga to be firm restraint of the senses. Then one becomes un-distracted for yoga is the arising and the passing away" 

Bhagavad Gita c. 2nd century BCE "Be equal minded in both success and failure. Such equanimity is called Yoga" 

"Yoga is skill in action"  "Know that which is called yoga to be separation from contact with suffering" 

Yoga Sutras of Patanjali c. first centuries CE 1.2. yogas chitta vritti nirodhah - "Yoga is the calming down the fluctuations/patterns of mind"

1.3. Then the Seer is established in his own essential and fundamental nature.

1.4. In other states there is assimilation (of the Seer) with the modifications (of the mind).

Yogācārabhūmi-Śāstra (Sravakabhumi), a Mahayana Buddhist Yogacara work 4th century CE "Yoga is fourfold: faith, aspiration, perseverance and means" 

Kaundinya's Pancarthabhasya on the Pasupatasutra 4th century CE "In this system, yoga is the union of the self and the Lord" 

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 Self's] contact with the causes of these [three], due to the common usage of the cause for the effect." .

Linga Purana 7th-10th century CE "By the word 'yoga' is meant nirvana, the condition of Shiva." 

Brahmasutra-bhasya of Adi Shankara c. 8th century CE "It is said in the treatises on yoga: 'Yoga is the means of perceiving reality' (atha tattvadarsanabhyupāyo yogah)" 

Mālinīvijayottara Tantra, one of the primary authorities in non-dual Kashmir Shaivism 6th-10th century CE "Yoga is said to be the oneness of one entity with another." 

Mrgendratantravrtti, of the Shaiva Siddhanta scholar Narayanakantha 6th-10th century CE "To have self-mastery is to be a Yogin. The term Yogin means "one who is necessarily "conjoined with" the manifestation of his nature...the Siva-state (sivatvam)" (MrTaVr yp 2a)

Śaradatilaka of Lakshmanadesikendra, a Shakta Tantra work 11th century CE "Yogic experts state that yoga is the oneness of the individual Self (jiva) with the atman. Others understand it to be the ascertainment of Siva and the Self as non-different. The scholars of the Agamas say that it is a Knowledge which is of the nature of Siva's Power. Other scholars say it is the knowledge of the primordial Self." (SaTil 25.1–3b)[41]

Yogabija, a Hatha yoga work 14th century CE "The union of apana and prana, one's own rajas and semen, the sun and moon, the individual Self and the supreme Self, and in the same way the union of all dualities, is called yoga. " 

Goals

The ultimate goals of yoga are stilling the mind and gaining insight, resting in detached awareness, and liberation (Moksha) from saṃsāra and duḥkha: a process (or discipline) leading to unity (Aikyam) with the divine (Brahman) or with one's Self (Ātman). This goal varies by philosophical or theological system. In the classical Astanga yoga system, the ultimate goal of yoga is to achieve samadhi and remain in that state as pure awareness.

According to Knut A. Jacobsen, yoga has five principal meanings:

A disciplined method for attaining a goal

Techniques of controlling the body and mind

A name of a school or system of philosophy (darśana)

With prefixes such as "hatha-, mantra-, and laya-, traditions specialising in particular yoga techniques

The goal of Yoga practice

David Gordon White writes that yoga's core principles were more or less in place in the 5th century CE, and variations of the principles developed over time:

A meditative means of discovering dysfunctional perception and cognition, as well as overcoming it to release any suffering, find inner peace, and salvation. Illustration of this principle is found in Hindu texts such as the Bhagavad Gita and Yogasutras, in a number of Buddhist Mahāyāna works, as well as Jain texts.

The raising and expansion of consciousness from oneself to being coextensive with everyone and everything. These are discussed in sources such as in Hinduism Vedic literature and its epic Mahābhārata, the Jain Praśamaratiprakarana, and Buddhist Nikaya texts.

A technique for entering into other bodies, generating multiple bodies, and the attainment of other supernatural accomplishments. These are, states White, described in Tantric literature of Hinduism and Buddhism, as well as the Buddhist Sāmaññaphalasutta. James Mallinson, however, disagrees and suggests that such fringe practices are far removed from the mainstream Yoga's goal as meditation-driven means to liberation in Indian religions.

According to White, the last principle relates to legendary goals of yoga practice; it differs from yoga's practical goals in South Asian thought and practice since the beginning of the Common Era in Hindu, Buddhist, and Jain philosophical schools.

History

There is no consensus on yoga's chronology or origins other than its development in ancient India. There are two broad theories explaining the origins of yoga. The linear model holds that yoga has Vedic origins (as reflected in Vedic texts), and influenced Buddhism. This model is mainly supported by Hindu scholars. According to the synthesis model, yoga is a synthesis of indigenous, non-Vedic practices with Vedic elements. This model is favoured in Western scholarship.

Speculations about yoga began to emerge in the early Upanishads of the first half of the first millennium BCE, with expositions also appearing in Jain and Buddhist texts c. 500 – c. 200 BCE. Between 200 BCE and 500 CE, traditions of Hindu, Buddhist, and Jain philosophy were taking shape; teachings were collected as sutras, and a philosophical system of Patanjaliyogasastra began to emerge.

Gym

 Gym

Globe icon.

A gymnasium, also known as a gym, is a covered location for athletics. The word is derived from the ancient Greek term "gymnasium". They are commonly found in athletic and fitness centres, and as activity and learning spaces in educational institutions. "Gym" is also slang for "fitness centre", which is often an area for indoor recreation. A "gym" may include or describe adjacent open air areas as well. In Western countries, "gyms" (or pl: gymnasia") often describe places with indoor or outdoor courts for basketball, hockey, tennis, boxing or wrestling, and with equipment and machines used for physical development training, or to do exercises. In many European countries, Gymnasium (and variations of the word) also can describe a secondary school that prepares students for higher education at a university, with or without the presence of athletic courts, fields, or equipment.

Overview

Gymnasia apparatus like barbells, jumping board, running path, tennis-balls, cricket field, and fencing area are used as exercises. In safe weather, outdoor locations are the most conducive to health. Gyms were popular in ancient Greece. Their curricula included self-defense, gymnastica medica, or physical therapy to help the sick and injured, and for physical fitness and sports, from boxing to dancing to skipping rope.

Gymnasia also had teachers of wisdom and philosophy. Community gymnastic events were done as part of the celebrations during various village festivals. In ancient Greece there was a phrase of contempt, "He can neither swim nor write." After a while, however, Olympic athletes began training in buildings specifically designed for them.[4] Community sports never became as popular among ancient Romans as it had among the ancient Greeks. Gyms were used more as a preparation for military service or spectator sports. During the Roman Empire, the gymnastic art was forgotten. In the Dark Ages there were sword fighting tournaments and of chivalry; and after gunpowder was invented sword fighting began to be replaced by the sport of fencing, as well as schools of dagger fighting and wrestling and boxing.

In the 18th century, Salzmann, German clergyman, opened a gym in Thuringia teaching bodily exercises, including running and swimming. Clias and Volker established gyms in London, and in 1825, Doctor Charles Beck, a German immigrant, established the first gymnasium in the United States. It was found that gym pupils lose interest in doing the same exercises, partly because of age. Variety in exercises included skating, dancing, and swimming. Some gym activities can be done by 6 to 8-year-olds while age 16 has been considered mature enough for boxing and horseback riding.

In Ancient Greece, the gymnasion (γυμνάσιον) was a locality for both physical and intellectual education of young men. The latter meaning of intellectual education persisted in Greek, German and other languages to denote a certain type of school providing secondary education, the gymnasium, whereas in English the meaning of physical education pertained in the word 'gym'. The Greek word gymnasium, which means "school for naked exercise," was used to designate a locality for the education of young men, including physical education (gymnastics, for example, exercise) which was customarily performed naked, as well as bathing, and studies. For the Greeks, physical education was considered as important as cognitive learning. Most Greek gymnasia had libraries that for use after relaxing in the baths.

Nowadays, it represents a common area where people, from all ranges of experience, exercise and work out their muscles. You can also usually find people doing cardio exercises or pilates.

History

The first recorded gymnasiums date back to over 3000 years ago in ancient Persia, where they were known as zurkhaneh, areas that encouraged physical fitness. The larger Roman Baths often had attached fitness facilities, the baths themselves sometimes being decorated with mosaics of local champions of sport. Gyms in Germany were an outgrowth of the Turnplatz, an outdoor space for gymnastics founded by German educator Friedrich Jahn in 1811 and later promoted by the Turners, a nineteenth-century political and gymnastic movement. The first American to open a public gym in the United States using Jahn's model was John Neal of Portland, Maine in 1827. The first indoor gymnasium in Germany was probably the one built in Hesse in 1852 by Adolph Spiess.

Through worldwide colonization, Great Britain expanded its national interest in sports and games to many countries. In the 1800s, programs were added to schools and college curricula that emphasized health, strength, and bodily measure. Sports drawn from European and British cultures thrived as college students and upper-class clubs financed competition. As a result, towns began building playgrounds that furthered interest in sports and physical activity. Early efforts to establish gyms in the United States in the 1820s were documented and promoted by John Neal in the American Journal of Education and The Yankee, helping to establish the American branch of the movement. Later in the century, the Turner movement was founded and continued to thrive into the early twentieth century. The first Turners group was formed in London in 1848. The Turners built gymnasia in several cities like Cincinnati and St. Louis which had large German American populations. These gyms were utilized by adults and youth. For example, a young Lou Gehrig would frequent the Turner gym in New York City with his father.

The Boston Young Men's Christian Union claims to be "America's First Gym". The YMCA first organized in Boston in 1851 and a smaller branch opened in Rangasville in 1852. Ten years later there were some two hundred YMCAs across the country, most of which provided gymnasia for exercise, games, and social interaction.

The 1920s was a decade of prosperity that witnessed the building of large numbers of public high schools with a gymnasium, an idea founded by Nicolas Isaranga.

Today, gymnasia are commonplace in the United States. They are in virtually all U.S. colleges and high schools, as well as almost all middle schools and elementary schools. These facilities are used for physical education, intramural sports, and school gatherings. The number of gyms in the U.S. has more than doubled since the late 1980s.

Heart rate

 

Heart rate

Heart rate (or pulse rate) is the speed of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excrete carbon dioxide, but is also modulated by numerous factors, including, but not limited to, genetics, physical fitness, stress or psychological status, diet, drugs, hormonal status, environment, and disease/illness as well as the interaction between and among these factors. It  is usually equal or close to the pulse measured at any peripheral point.

The American Heart Association states the normal resting adult human heart rate is 60–100 bpm. Tachycardia is a high heart rate, defined as above 100 bpm at rest. Bradycardia is a low heart rate, defined as below 60 bpm at rest. When a human sleeps, a heartbeat with rates around 40–50 bpm is common and is considered normal. When the heart is not beating in a regular pattern, this is referred to as an arrhythmia. Abnormalities of heart rate sometimes indicate disease.

Physiology

Anatomy of the Human Heart, made by Ties van Brussel

Heart sounds of a 16 year old girl immediately after running, with a heart rate of 186 BPM. The S1 heart sound is intensified due to the increased cardiac output.

Problems playing this file? See media help.

While heart rhythm is regulated entirely by the sinoatrial node under normal conditions, heart rate is regulated by sympathetic and parasympathetic input to the sinoatrial node. The accelerans nerve provides sympathetic input to the heart by releasing norepinephrine onto the cells of the sinoatrial node (SA node), and the vagus nerve provides parasympathetic input to the heart by releasing acetylcholine onto sinoatrial node cells. Therefore, stimulation of the accelerans nerve increases heart rate, while stimulation of the vagus nerve decreases it.

As water and blood are incompressible fluids, one of the physiological ways to deliver more blood to an organ is to increase heart rate. Normal resting heart rates range from 60 to 100 bpm. Bradycardia is defined as a resting heart rate below 60 bpm. However, heart rates from 50 to 60 bpm are common among healthy people and do not necessarily require special attention. Tachycardia is defined as a resting heart rate above 100 bpm, though persistent rest rates between 80 and 100 bpm, mainly if they are present during sleep, may be signs of hyperthyroidism or anemia .

Central nervous system stimulants such as substituted amphetamines increase heart rate.

Central nervous system depressants or sedatives decrease the heart rate (apart from some particularly strange ones with equally strange effects, such as ketamine which can cause – amongst many other things – stimulant-like effects such as tachycardia).

There are many ways in which the heart rate speeds up or slows down. Most involve stimulant-like endorphins and hormones being released in the brain, some of which are those that are 'forced'/'enticed' out by the ingestion and processing of drugs such as cocaine or atropine.

This section discusses target heart rates for healthy persons, which would be inappropriately high for most persons with coronary artery disease.

Influences from the central nervous system

Cardiovascular centres

The heart rate is rhythmically generated by the sinoatrial node. It is also influenced by central factors through sympathetic and parasympathetic nerves. Nervous influence over the heart rate is centralized within the two paired cardiovascular centres of the medulla oblongata. The cardioaccelerator regions stimulate activity via sympathetic stimulation of the cardioaccelerator nerves, and the cardioinhibitory centers decrease heart activity via parasympathetic stimulation as one component of the vagus nerve. During rest, both centers provide slight stimulation to the heart, contributing to autonomic tone. This is a similar concept to tone in skeletal muscles. Normally, vagal stimulation predominates as, left unregulated, the SA node would initiate a sinus rhythm of approximately 100 bpm.

Both sympathetic and parasympathetic stimuli flow through the paired cardiac plexus near the base of the heart. The cardioaccelerator center also sends additional fibers, forming the cardiac nerves via sympathetic ganglia (the cervical ganglia plus superior thoracic ganglia T1–T4) to both the SA and AV nodes, plus additional fibers to the atria and ventricles. The ventricles are more richly innervated by sympathetic fibers than parasympathetic fibers. Sympathetic stimulation causes the release of the neurotransmitter norepinephrine (also known as noradrenaline) at the neuromuscular junction of the cardiac nerves. This shortens the repolarization period, thus speeding the rate of depolarization and contraction, which results in an increased heartrate. It opens chemical or ligand-gated sodium and calcium ion channels, allowing an influx of positively charged ions.

Norepinephrine binds to the beta–1 receptor. High blood pressure medications are used to block these receptors and so reduce the heart rate.

Parasympathetic stimulation originates from the cardioinhibitory region of the brain with impulses traveling via the vagus nerve (cranial nerve X). The vagus nerve sends branches to both the SA and AV nodes, and to portions of both the atria and ventricles. Parasympathetic stimulation releases the neurotransmitter acetylcholine (ACh) at the neuromuscular junction. ACh slows HR by opening chemical- or ligand-gated potassium ion channels to slow the rate of spontaneous depolarization, which extends repolarization and increases the time before the next spontaneous depolarization occurs. Without any nervous stimulation, the SA node would establish a sinus rhythm of approximately 100 bpm. Since resting rates are considerably less than this, it becomes evident that parasympathetic stimulation normally slows HR. This is similar to an individual driving a car with one foot on the brake pedal. To speed up, one need merely remove one's foot from the brake and let the engine increase speed. In the case of the heart, decreasing parasympathetic stimulation decreases the release of ACh, which allows HR to increase up to approximately 100 bpm. Any increases beyond this rate would require sympathetic stimulation.

Input to the cardiovascular centres

The cardiovascular centres receive input from a series of visceral receptors with impulses traveling through visceral sensory fibers within the vagus and sympathetic nerves via the cardiac plexus. Among these receptors are various proprioreceptors, baroreceptors, and chemoreceptors, plus stimuli from the limbic system which normally enable the precise regulation of heart function, via cardiac reflexes. Increased physical activity results in increased rates of firing by various proprioreceptors located in muscles, joint capsules, and tendons. The cardiovascular centres monitor these increased rates of firing, suppressing parasympathetic stimulation or increasing sympathetic stimulation as needed in order to increase blood flow.

Similarly, baroreceptors are stretch receptors located in the aortic sinus, carotid bodies, the venae cavae, and other locations, including pulmonary vessels and the right side of the heart itself. Rates of firing from the baroreceptors represent blood pressure, level of physical activity, and the relative distribution of blood. The cardiac centers monitor baroreceptor firing to maintain cardiac homeostasis, a mechanism called the baroreceptor reflex. With increased pressure and stretch, the rate of baroreceptor firing increases, and the cardiac centers decrease sympathetic stimulation and increase parasympathetic stimulation. As pressure and stretch decrease, the rate of baroreceptor firing decreases, and the cardiac centers increase sympathetic stimulation and decrease parasympathetic stimulation.

There is a similar reflex, called the atrial reflex or Bainbridge reflex, associated with varying rates of blood flow to the atria. Increased venous return stretches the walls of the atria where specialized baroreceptors are located. However, as the atrial baroreceptors increase their rate of firing and as they stretch due to the increased blood pressure, the cardiac center responds by increasing sympathetic stimulation and inhibiting parasympathetic stimulation to increase HR. The opposite is also true.

Increased metabolic byproducts associated with increased activity, such as carbon dioxide, hydrogen ions, and lactic acid, plus falling oxygen levels, are detected by a suite of chemoreceptors innervated by the glossopharyngeal and vagus nerves. These chemoreceptors provide feedback to the cardiovascular centers about the need for increased or decreased blood flow, based on the relative levels of these substances.

The limbic system can also significantly impact HR related to emotional state. During periods of stress, it is not unusual to identify higher than normal HRs, often accompanied by a surge in the stress hormone cortisol. Individuals experiencing extreme anxiety may manifest panic attacks with symptoms that resemble those of heart attacks. These events are typically transient and treatable. Meditation techniques have been developed to ease anxiety and have been shown to lower HR effectively. Doing simple deep and slow breathing exercises with one's eyes closed can also significantly reduce this anxiety and HR.

Factors influencing heart rate

Table 1: Major factors increasing heart rate and force of contraction

Factor Effect

Cardioaccelerator nerves Release of norepinephrine

Proprioreceptors Increased rates of firing during exercise

Chemoreceptors Decreased levels of O2; increased levels of H+, CO2, and lactic acid

Baroreceptors Decreased rates of firing, indicating falling blood volume/pressure

Limbic system Anticipation of physical exercise or strong emotions

Catecholamines Increased epinephrine and norepinephrine

Thyroid hormones Increased T3 and T4

Calcium Increased Ca2+

Potassium Decreased K+

Sodium Decreased Na+

Body temperature Increased body temperature

Nicotine and caffeine Stimulants, increasing heart rate

Table 2: Factors decreasing heart rate and force of contraction

Factor Effect

Cardioinhibitor nerves (vagus) Release of acetylcholine

Proprioreceptors Decreased rates of firing following exercise

Chemoreceptors Increased levels of O2; decreased levels of H+ and CO2

Baroreceptors Increased rates of firing, indicating higher blood volume/pressure

Limbic system Anticipation of relaxation

Catecholamines Decreased epinephrine and norepinephrine

Thyroid hormones Decreased T3 and T4

Calcium Decreased Ca2+

Potassium Increased K+

Sodium Increased Na+

Body temperature Decrease in body temperature

Using a combination of autorhythmicity and innervation, the cardiovascular center is able to provide relatively precise control over the heart rate, but other factors can impact on this. These include hormones, notably epinephrine, norepinephrine, and thyroid hormones; levels of various ions including calcium, potassium, and sodium; body temperature; hypoxia; and pH balance.

Epinephrine and norepinephrine

The catecholamines, epinephrine and norepinephrine, secreted by the adrenal medulla form one component of the extended fight-or-flight mechanism. The other component is sympathetic stimulation. Epinephrine and norepinephrine have similar effects: binding to the beta-1 adrenergic receptors, and opening sodium and calcium ion chemical- or ligand-gated channels. The rate of depolarization is increased by this additional influx of positively charged ions, so the threshold is reached more quickly and the period of repolarization is shortened. However, massive releases of these hormones coupled with sympathetic stimulation may actually lead to arrhythmias. There is no parasympathetic stimulation to the adrenal medulla.

Thyroid hormones

In general, increased levels of the thyroid hormones (thyroxine(T4) and triiodothyronine (T3)), increase the heart rate; excessive levels can trigger tachycardia. The impact of thyroid hormones is typically of a much longer duration than that of the catecholamines. The physiologically active form of triiodothyronine, has been shown to directly enter cardiomyocytes and alter activity at the level of the genome. It also impacts the beta adrenergic response similar to epinephrine and norepinephrine.

Calcium

Calcium ion levels have a great impact on heart rate and contractility: increased calcium levels cause an increase in both. High levels of calcium ions result in hypercalcemia and excessive levels can induce cardiac arrest. Drugs known as calcium channel blockers slow HR by binding to these channels and blocking or slowing the inward movement of calcium ions.

Caffeine and nicotine

Caffeine and nicotine are both stimulants of the nervous system and of the cardiac centres causing an increased heart rate. Caffeine works by increasing the rates of depolarization at the SA node, whereas nicotine stimulates the activity of the sympathetic neurons that deliver impulses to the heart. Both stimulants are legal and unregulated, and nicotine is very addictive.

Effects of stress

Both surprise and stress induce physiological response: elevate heart rate substantially. In a study conducted on 8 female and male student actors ages 18 to 25, their reaction to an unforeseen occurrence (the cause of stress) during a performance was observed in terms of heart rate. In the data collected, there was a noticeable trend between the location of actors (onstage and offstage) and their elevation in heart rate in response to stress; the actors present offstage reacted to the stressor immediately, demonstrated by their immediate elevation in heart rate the minute the unexpected event occurred, but the actors present onstage at the time of the stressor reacted in the following 5 minute period (demonstrated by their increasingly elevated heart rate). This trend regarding stress and heart rate is supported by previous studies; negative emotion/stimulus has a prolonged effect on heart rate in individuals who are directly impacted. In regard to the characters present onstage, a reduced startle response has been associated with a passive defense, and the diminished initial heart rate response has been predicted to have a greater tendency to dissociation. Current evidence suggests that heart rate variability can be used as an accurate measure of psychological stress and may be used for an objective measurement of psychological stress.

Factors decreasing heart rate

The heart rate can be slowed by altered sodium and potassium levels, hypoxia, acidosis, alkalosis, and hypothermia. The relationship between electrolytes and HR is complex, but maintaining electrolyte balance is critical to the normal wave of depolarization. Of the two ions, potassium has the greater clinical significance. Initially, both hyponatremia (low sodium levels) and hypernatremia (high sodium levels) may lead to tachycardia. Severely high hypernatremia may lead to fibrillation, which may cause CO to cease. Severe hyponatremia leads to both bradycardia and other arrhythmias. Hypokalemia (low potassium levels) also leads to arrhythmias, whereas hyperkalemia (high potassium levels) causes the heart to become weak and flaccid, and ultimately to fail.

Heart muscle relies exclusively on aerobic metabolism for energy. Severe myocardial infarction (commonly called a heart attack) can lead to a decreasing heart rate, since metabolic reactions fueling heart contraction are restricted.

Acidosis is a condition in which excess hydrogen ions are present, and the patient's blood expresses a low pH value. Alkalosis is a condition in which there are too few hydrogen ions, and the patient's blood has an elevated pH. Normal blood pH falls in the range of 7.35–7.45, so a number lower than this range represents acidosis and a higher number represents alkalosis. Enzymes, being the regulators or catalysts of virtually all biochemical reactions – are sensitive to pH and will change shape slightly with values outside their normal range. These variations in pH and accompanying slight physical changes to the active site on the enzyme decrease the rate of formation of the enzyme-substrate complex, subsequently decreasing the rate of many enzymatic reactions, which can have complex effects on HR. Severe changes in pH will lead to denaturation of the enzyme.

The last variable is body temperature. Elevated body temperature is called hyperthermia, and suppressed body temperature is called hypothermia. Slight hyperthermia results in increasing HR and strength of contraction. Hypothermia slows the rate and strength of heart contractions. This distinct slowing of the heart is one component of the larger diving reflex that diverts blood to essential organs while submerged. If sufficiently chilled, the heart will stop beating, a technique that may be employed during open heart surgery. In this case, the patient's blood is normally diverted to an artificial heart-lung machine to maintain the body's blood supply and gas exchange until the surgery is complete, and sinus rhythm can be restored. Excessive hyperthermia and hypothermia will both result in death, as enzymes drive the body systems to cease normal function, beginning with the central nervous system.

Weight loss

 

Weight loss

Weight loss, in the context of medicine, health, or physical fitness, refers to a reduction of the total body mass, by a mean loss of fluid, body fat (adipose tissue), or lean mass (namely bone mineral deposits, muscle, tendon, and other connective tissue). Weight loss can either occur unintentionally because of malnourishment or an underlying disease, or from a conscious effort to improve an actual or perceived overweight or obese state. "Unexplained" weight loss that is not caused by reduction in calorific intake or exercise is called cachexia and may be a symptom of a serious medical condition. Intentional weight loss is commonly referred to as slimming.

Intentional

Intentional weight loss is the loss of total body mass as a result of efforts to improve fitness and health, or to change appearance through slimming. Weight loss is the main treatment for obesity, and there is substantial evidence this can prevent progression from prediabetes to type 2 diabetes with a 7-10% weight loss and manage cardiometabolic health for diabetic people with a 5-15% weight loss.

Weight loss in individuals who are overweight or obese can reduce health risks, increase fitness, and may delay the onset of diabetes. It could reduce pain and increase movement in people with osteoarthritis of the knee. Weight loss can lead to a reduction in hypertension (high blood pressure), however whether this reduces hypertension-related harm is unclear. failed verification Weight loss is achieved by adopting a lifestyle in which fewer calories are consumed than are expended. Depression, stress or boredom may contribute to weight increase, and in these cases, individuals are advised to seek medical help. A 2010 study found that dieters who got a full night's sleep lost more than twice as much fat as sleep-deprived dieters. Though hypothesized that supplementation of vitamin D may help, studies do not support this. The majority of dieters regain weight over the long term. According to the UK National Health Service and the Dietary Guidelines for Americans, those who achieve and manage a healthy weight do so most successfully by being careful to consume just enough calories to meet their needs, and being physically active.

For weight loss to be permanent, changes in diet and lifestyle must be permanent as well. There is evidence that counseling or exercise alone do not result in weight loss, whereas dieting alone results in meaningful long-term weight loss, and a combination of dieting and exercise provides the best results. Meal replacements, orlistat and very-low-calorie diet interventions also produce meaningful weight loss.

Techniques

See also: Management of obesity

The least intrusive weight loss methods, and those most often recommended, are adjustments to eating patterns and increased physical activity, generally in the form of exercise. The World Health Organization recommends that people combine a reduction of processed foods high in saturated fats, sugar and salt[19] and caloric content of the diet with an increase in physical activity. Self-monitoring of diet, exercise, and weight are beneficial strategies for weight loss, particularly early in weight loss programs.[23] Research indicates that those who log their foods about three times per day and about 20 times per month are more likely to achieve clinically significant weight loss.

The cardboard packaging of two medications used to treat obesity. Orlistat is shown above under the brand name Xenical in a white package with Roche branding. Sibutramine is below under the brand name Meridia. Orlistat is also available as Alli in the United Kingdom. The A of the Abbott Laboratories logo is on the bottom half of the package.

Orlistat (Xenical) the most commonly used medication to treat obesity and sibutramine (Meridia) a withdrawn medication due to cardiovascular side effects

An increase in fiber intake is recommended for regulating bowel movements. Other methods of weight loss include use of drugs and supplements that decrease appetite, block fat absorption, or reduce stomach volume. Bariatric surgery may be indicated in cases of severe obesity. Two common bariatric surgical procedures are gastric bypass and gastric banding. Both can be effective at limiting the intake of food energy by reducing the size of the stomach, but as with any surgical procedure both come with their own risks[26] that should be considered in consultation with a physician. Dietary supplements, though widely used, are not considered a healthy option for weight loss. Many are available, but very few are effective in the long term.

Virtual gastric band uses hypnosis to make the brain think the stomach is smaller than it really is and hence lower the amount of food ingested. This brings as a consequence weight reduction. This method is complemented with psychological treatment for anxiety management and with hypnopedia. Research has been conducted into the use of hypnosis as a weight management alternative. In 1996, a study found that cognitive-behavioral therapy was more effective for weight reduction if reinforced with hypnosis. Acceptance and commitment therapy, a mindfulness approach to weight loss, has been demonstrated as useful. Herbal medications have also been suggested; however, there is no strong evidence that herbal medicines are effective.

Weight loss industry

There is a substantial market for products which claim to make weight loss easier, quicker, cheaper, more reliable, or less painful. These include books, DVDs, CDs, cremes, lotions, pills, rings and earrings, body wraps, body belts and other materials, fitness centers, clinics, personal coaches, weight loss groups, and food products and supplements.

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 per year was spent on weight-loss supplements. About 70 percent of Americans' dieting attempts are of a self-help nature.

In Western Europe, sales of weight-loss products, excluding prescription medications, topped €1,25 billion (£900 million/$1.4 billion) in 2009.

The scientific soundness of commercial diets by commercial weight management organizations varies widely, being previously non-evidence-based, so there is only limited evidence supporting their use, because of high attrition rates. Commercial diets result in modest weight loss in the long term, with similar results regardless of the brand, and similarly to non-commercial diets and standard care. Comprehensive diet programs, providing counseling and targets for calorie intake, are more efficient than dieting without guidance ("self-help"), although the evidence is very limited. The National Institute for Health and Care Excellence devised a set of essential criteria to be met by commercial weight management organizations to be approved.

Unintentional

Characteristics

Unintentional weight loss may result from loss of body fats, loss of body fluids, muscle atrophy, or a combination of these.[47][48] It is generally regarded as a medical problem when at least 10% of a person's body weight has been lost in six months[47][49] or 5% in the last month. Another criterion used for assessing weight that is too low is the body mass index (BMI). However, even lesser amounts of weight loss can be a cause for serious concern in a frail elderly person.

Unintentional weight loss can occur because of an inadequately nutritious diet relative to a person's energy needs (generally called malnutrition). Disease processes, changes in metabolism, hormonal changes, medications or other treatments, disease- or treatment-related dietary changes, or reduced appetite associated with a disease or treatment can also cause unintentional weight loss. Poor nutrient utilization can lead to weight loss, and can be caused by fistulae in the gastrointestinal tract, diarrhea, drug-nutrient interaction, enzyme depletion and muscle atrophy.

Continuing weight loss may deteriorate into wasting, a vaguely defined condition called cachexia. Cachexia differs from starvation in part because it involves a systemic inflammatory response. It is associated with poorer outcomes. In the advanced stages of progressive disease, metabolism can change so that they lose weight even when they are getting what is normally regarded as adequate nutrition and the body cannot compensate. This leads to a condition called anorexia cachexia syndrome (ACS) and additional nutrition or supplementation is unlikely to help. Symptoms of weight loss from ACS include severe weight loss from muscle rather than body fat, loss of appetite and feeling full after eating small amounts, nausea, anemia, weakness and fatigue.

Serious weight loss may reduce quality of life, impair treatment effectiveness or recovery, worsen disease processes and be a risk factor for high mortality rates. Malnutrition can affect every function of the human body, from the cells to the most complex body functions, including:

immune response;

wound healing;

muscle strength (including respiratory muscles);

renal capacity and depletion leading to water and electrolyte disturbances;

thermoregulation; and

menstruation.

Malnutrition can lead to vitamin and other deficiencies and to inactivity, which in turn may pre-dispose to other problems, such as pressure sores.Unintentional weight loss can be the characteristic leading to diagnosis of diseases such as cancer and type 1 diabetes.[56] In the UK, up to 5% of the general population is underweight, but more than 10% of those with lung or gastrointestinal diseases and who have recently had surgery. According to data in the UK using the Malnutrition Universal Screening Tool ('MUST'), which incorporates unintentional weight loss, more than 10% of the population over the age of 65 is at risk of malnutrition. A high proportion (10–60%) of hospital patients are also at risk, along with a similar proportion in care homes.

Causes

Disease-related

Disease-related malnutrition can be considered in four categories:

Problem Cause

Impaired intake Poor appetite can be a direct symptom of an illness, or an illness could make eating painful or induce nausea. Illness can also cause food aversion.

Inability to eat can result from: diminished consciousness or confusion, or physical problems affecting the arm or hands, swallowing or chewing. Eating restrictions may also be imposed as part of treatment or investigations. Lack of food can result from: poverty, difficulty in shopping or cooking, and poor quality meals.

Impaired digestion &/or absorption This can result from conditions that affect the digestive system.

Altered requirements Changes to metabolic demands can be caused by illness, surgery and organ dysfunction.

Excess nutrient losses Losses from the gastrointestinal can occur because of symptoms such as vomiting or diarrhea, as well as fistulae and stomas. There can also be losses from drains, including nasogastric tubes.

Other losses: Conditions such as burns can be associated with losses such as skin exudates.

Weight loss issues related to specific diseases include:

As chronic obstructive pulmonary disease (COPD) advances, about 35% of patients experience severe weight loss called pulmonary cachexia, including diminished muscle mass. Around 25% experience moderate to severe weight loss, and most others have some weight loss. Greater weight loss is associated with poorer prognosis. Theories about contributing factors include appetite loss related to reduced activity, additional energy required for breathing, and the difficulty of eating with dyspnea (labored breathing).

Cancer, a very common and sometimes fatal cause of unexplained (idiopathic) weight loss. About one-third of unintentional weight loss cases are secondary to malignancy. Cancers to suspect in patients with unexplained weight loss include gastrointestinal, prostate, hepatobiliary (hepatocellular carcinoma, pancreatic cancer), ovarian, hematologic or lung malignancies.

People with HIV often experience weight loss, and it is associated with poorer outcomes. Wasting syndrome is an AIDS-defining condition.

Gastrointestinal disorders are another common cause of unexplained weight loss – in fact they are the most common non-cancerous cause of idiopathic weight loss.[citation needed] Possible gastrointestinal etiologies of unexplained weight loss include: celiac disease, peptic ulcer disease, inflammatory bowel disease (crohn's disease and ulcerative colitis), pancreatitis, gastritis, diarrhea, chronic mesenteric ischemia and many other GI conditions.

Infection. Some infectious diseases can cause weight loss. Fungal illnesses, endocarditis, many parasitic diseases, AIDS, and some other subacute or occult infections may cause weight loss.

Renal disease. Patients who have uremia often have poor or absent appetite, vomiting and nausea. This can cause weight loss.

Cardiac disease. Cardiovascular disease, especially congestive heart failure, may cause unexplained weight loss.

Connective tissue disease

Oral, taste or dental problems (including infections) can reduce nutrient intake leading to weight loss.

Therapy-related

Medical treatment can directly or indirectly cause weight loss, impairing treatment effectiveness and recovery that can lead to further weight loss in a vicious cycle. Many patients will be in pain and have a loss of appetite after surgery. Part of the body's response to surgery is to direct energy to wound healing, which increases the body's overall energy requirements. Surgery affects nutritional status indirectly, particularly during the recovery period, as it can interfere with wound healing and other aspects of recovery. Surgery directly affects nutritional status if a procedure permanently alters the digestive system. Enteral nutrition (tube feeding) is often needed. However a policy of 'nil by mouth' for all gastrointestinal surgery has not been shown to benefit, with some weak evidence suggesting it might hinder recovery. Early post-operative nutrition is a part of Enhanced Recovery After Surgery protocols. These protocols also include carbohydrate loading in the 24 hours before surgery, but earlier nutritional interventions have not been shown to have a significant impact.

Social conditions

Social conditions such as poverty, social isolation and inability to get or prepare preferred foods can cause unintentional weight loss, and this may be particularly common in older people. Nutrient intake can also be affected by culture, family and belief systems. Ill-fitting dentures and other dental or oral health problems can also affect adequacy of nutrition.

Loss of hope, status or social contact and spiritual distress can cause depression, which may be associated with reduced nutrition, as can fatigue.

Myths

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 metabolic rate 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. They also commented that the idea of changing one's rate of metabolism is under debate. 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.

Health effects

Further information: Obesity § Effects on health

Obesity increases health risks, including diabetes, cancer, cardiovascular disease, high blood pressure, and non-alcoholic fatty liver disease, to name a few. Reduction of obesity lowers those risks. A 1-kg loss of body weight has been associated with an approximate 1-mm Hg drop in blood pressure. Intentional weight loss is associated with cognitive performance improvements in overweight and obese individuals.

Health

 

Health

Health, according to the World Health Organization, is "a state of complete physical, mental and social well-being and not merely the absence of disease and infirmity". A variety of definitions have been used for different purposes over time. Health can be promoted by encouraging healthful activities, such as regular physical exercise and adequate sleep, and by reducing or avoiding unhealthful activities or situations, such as smoking or excessive stress. Some factors affecting health are due to individual choices, such as whether to engage in a high-risk behavior, while others are due to structural causes, such as whether the society is arranged in a way that makes it easier or harder for people to get necessary healthcare services. Still other factors are beyond both individual and group choices, such as genetic disorders.

History

The meaning of health has evolved over time. In keeping with the biomedical perspective, early definitions of health focused on the theme of the body's ability to function; health was seen as a state of normal function that could be disrupted from time to time by disease. An example of such a definition of health is: "a state characterized by anatomic, physiologic, and psychological integrity; ability to perform personally valued family, work, and community roles; ability to deal with physical, biological, psychological, and social stress". Then, in 1948, in a radical departure from previous definitions, the World Health Organization (WHO) proposed a definition that aimed higher, linking health to well-being, in terms of "physical, mental, and social well-being, and not merely the absence of disease and infirmity". Although this definition was welcomed by some as being innovative, it was also criticized for being vague and excessively broad and was not construed as measurable. For a long time, it was set aside as an impractical ideal, with most discussions of health returning to the practicality of the biomedical model.

Just as there was a shift from viewing disease as a state to thinking of it as a process, the same shift happened in definitions of health. Again, the WHO played a leading role when it fostered the development of the health promotion movement in the 1980s. This brought in a new conception of health, not as a state, but in dynamic terms of resiliency, in other words, as "a resource for living". In 1984, WHO revised the definition of health defined it as "the extent to which an individual or group is able to realize aspirations and satisfy needs and to change or cope with the environment. Health is a resource for everyday life, not the objective of living; it is a positive concept, emphasizing social and personal resources, as well as physical capacities." Thus, health referred to the ability to maintain homeostasis and recover from adverse events. Mental, intellectual, emotional and social health referred to a person's ability to handle stress, to acquire skills, to maintain relationships, all of which form resources for resiliency and independent living. This opens up many possibilities for health to be taught, strengthened and learned.

Since the late 1970s, the federal Healthy People Program has been a visible component of the United States’ approach to improving population health.[7][8] In each decade, a new version of Healthy People is issued,[9] 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.

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. These are referred to as the "determinants of health", which include the individual's background, lifestyle, economic status, social conditions and spirituality; Studies have shown that high levels of stress can affect human health.

In the first decade of the 21st century, the conceptualization of health as an ability opened the door for self-assessments to become the main indicators to judge the performance of efforts aimed at improving human health. It also created the opportunity for every person to feel healthy, even in the presence of multiple chronic diseases or a terminal condition, and for the re-examination of determinants of health (away from the traditional approach that focuses on the reduction of the prevalence of diseases).

Determinants

See also: Social determinants of health and Risk factor

In general, the context in which an individual lives is of great importance for both his health status and quality of 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.

More specifically, key factors that have been found to influence whether people are healthy or unhealthy include the following:

Income and social status

Social support networks

Education and literacy

Employment/working conditions

Social environments

Physical environments

Personal health practices and coping skills

Healthy child development

Biology and genetics

Health care services

Gender

Culture

Donald Henderson as part of the CDC's smallpox eradication team in 1966.

An increasing number of studies and reports from different organizations and contexts examine the linkages between health and different factors, including lifestyles, environments, health care organization and health policy, one specific health policy brought into many countries in recent years was the introduction of the sugar tax. Beverage taxes came into light with increasing concerns about obesity, particularly among youth. Sugar-sweetened beverages have become a target of anti-obesity initiatives with increasing evidence of their link to obesity.– such as the 1974 Lalonde report from Canada;[16] the Alameda County Study in California; and the series of World Health Reports of the World Health Organization, which focuses on global health issues including access to health care and improving public health outcomes, especially in developing countries.

The concept of the "health field," as distinct from medical care, emerged from the Lalonde report from Canada. The report identified three interdependent fields as key determinants of an individual's health. These are:

Lifestyle: the aggregation of personal decisions (i.e., over which the individual has control) that can be said to contribute to, or cause, illness or death;

Environmental: all matters related to health external to the human body and over which the individual has little or no control;

Biomedical: all aspects of health, physical and mental, developed within the human body as influenced by genetic make-up.

The maintenance and promotion of health is achieved through different combination of physical, mental, and social well-being—a combination sometimes referred to as the "health triangle." The WHO's 1986 Ottawa Charter for Health Promotion further stated that health is not just a state, but also "a resource for everyday life, not the objective of living. Health is a positive concept emphasizing social and personal resources, as well as physical capacities."

Focusing more on lifestyle issues and their relationships with functional health, data from the Alameda County Study suggested that people can improve their health via exercise, enough sleep, spending time in nature, maintaining a healthy body weight, limiting alcohol use, and avoiding smoking. Health and illness can co-exist, as even people with multiple chronic diseases or terminal illnesses can consider themselves healthy.

The environment is often cited as an important factor influencing the health status of individuals. This includes characteristics of the natural environment, the built environment and the social environment. Factors such as clean water and air, adequate housing, and safe communities and roads all have been found to contribute to good health, especially to the health of infants and children. Some studies have shown that a lack of neighborhood recreational spaces including natural environment leads to lower levels of personal satisfaction and higher levels of obesity, linked to lower overall health and well-being. It has been demonstrated that increased time spent in natural environments is associated with improved self-reported health, suggesting that the positive health benefits of natural space in urban neighborhoods should be taken into account in public policy and land use.

Genetics, or inherited traits from parents, also play a role in determining the health status of individuals and populations. This can encompass both the predisposition to certain diseases and health conditions, as well as the habits and behaviors individuals develop through the lifestyle of their families. For example, genetics may play a role in the manner in which people cope with stress, either mental, emotional or physical. For example, obesity is a significant problem in the United States that contributes to poor mental health and causes stress in the lives of many people.[28] One difficulty is the issue raised by the debate over the relative strengths of genetics and other factors; interactions between genetics and environment may be of particular importance.

Potential issues

A number of health issues are common around the globe. Disease is one of the most common. According to GlobalIssues.org, approximately 36 million people die each year from non-communicable (i.e., not contagious) diseases, including cardiovascular disease, cancer, diabetes and chronic lung disease.

Among communicable diseases, both viral and bacterial, AIDS/HIV, tuberculosis, and malaria are the most common, causing millions of deaths every year.

Another health issue that causes death or contributes to other health problems is malnutrition, especially among children. One of the groups malnutrition affects most is young children. Approximately 7.5 million children under the age of 5 die from malnutrition, usually brought on by not having the money to find or make food.

Bodily injuries are also a common health issue worldwide. These injuries, including bone fractures and burns, can reduce a person's quality of life or can cause fatalities including infections that resulted from the injury (or the severity injury in general).

Lifestyle choices are contributing factors to poor health in many cases. These include smoking cigarettes, and can also include a poor diet, whether it is overeating or an overly constrictive diet. Inactivity can also contribute to health issues and also a lack of sleep, excessive alcohol consumption, and neglect of oral hygiene. There are also genetic disorders that are inherited by the person and can vary in how much they affect the person (and when they surface).[30]

Although the majority of these health issues are preventable, a major contributor to global ill health is the fact that approximately 1 billion people lack access to health care systems.[29] Arguably, the most common and harmful health issue is that a great many people do not have access to quality remedies.

Mental health

Main article: Mental health

The World Health Organization describes mental health as "a state of well-being in which the individual realizes his or her own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community". Mental health is not just the absence of mental illness.

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'.

Approximately twenty percent of all adults in the US are considered diagnosable with a mental illness. Mental illnesses are the leading cause of disability in the US and Canada. Examples of these illnesses include schizophrenia, ADHD, major depressive disorder, bipolar disorder, anxiety disorder, post-traumatic stress disorder and autism.

 Many factors contribute to mental health problems, including:

Biological factors, such as genes or brain chemistry

Life experiences, such as trauma or abuse

Family history of mental health problems

Maintaining

Achieving and maintaining health is an ongoing process, shaped by both the evolution of health care knowledge and practices as well as personal strategies and organized interventions for staying healthy.

Diet

Main articles: Healthy diet and Human nutrition

Percentage of overweight or obese population in 2010, Data source: OECD's iLibrary.

Percentage of obese population in 2010, Data source: OECD's iLibrary.

An important way to maintain one's personal health is to have a healthy diet. A healthy diet includes a variety of plant-based and animal-based foods that provide nutrients to the body. Such nutrients provide the body with energy and keep it running. Nutrients help build and strengthen bones, muscles, and tendons and also regulate body processes (i.e., blood pressure). Water is essential for growth, reproduction and good health. Macronutrients are consumed in relatively large quantities and include proteins, carbohydrates, and fats and fatty acids. Micronutrients – vitamins and minerals – are consumed in relatively smaller quantities, but are essential to body processes. The food guide pyramid is a pyramid-shaped guide of healthy foods divided into sections. Each section shows the recommended intake for each food group (i.e., protein, fat, carbohydrates and sugars). Making healthy food choices can lower one's risk of heart disease and the risk of developing some types of cancer, and can help one maintain their weight within a healthy range.

The Mediterranean diet is commonly associated with health-promoting effects. This is sometimes attributed to the inclusion of bioactive compounds such as phenolic compounds, isoprenoids and alkaloids.

Exercise

Main article: Exercise

Physical exercise enhances or maintains physical fitness and overall health and wellness. It strengthens one's bones and muscles and improves the cardiovascular system. According to the National Institutes of Health, there are four types of exercise: endurance, strength, flexibility, and balance.The CDC states that physical exercise can reduce the risks of heart disease, cancer, type 2 diabetes, high blood pressure, obesity, depression, and anxiety. For the purpose of counteracting possible risks, it is often recommended to start physical exercise gradually as one goes. Participating in any exercising, whether it is housework, yardwork, walking or standing up when talking on the phone, is often thought to be better than none when it comes to health.

Sleep

Main articles: Sleep and Sleep deprivation

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."

Age and condition Sleep Needs

Newborns (0–3 months) 14 to 17 hours

Infants (4–11 months) 12 to 15 hours

Toddlers (1–2 years) 11 to 14 hours

Preschoolers (3–5 years) 10 to 13 hours

School-age children (6–13 years)      9 to 11 hours

Teenagers (14–17 years)   8 to 10 hours

Adults (18–64 years)   7 to 9 hours

Older Adults (65 years and over)   7 to 8 hours

Role of science

Main articles: Health science and Health care

File:Nieuws uit Indonesië, het werk van de Nederlandse dienst voor Volksgezondheid Weeknummer 46-21 - Open Beelden - 16742.ogv

The Dutch Public Health Service provides medical care for the natives of the Dutch East Indies, May 1946

Health science is the branch of science focused on health. There are two main approaches to health science: the study and research of the body and health-related issues to understand how humans (and animals) function, and the application of that knowledge to improve health and to prevent and cure diseases and other physical and mental impairments. The science builds on many sub-fields, including biology, biochemistry, physics, epidemiology, pharmacology, medical sociology. Applied health sciences endeavor to better understand and improve human health through applications in areas such as health education, biomedical engineering, biotechnology and public health.

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 being 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.

Role of medicine and medical science

Main article: Medicine

Contemporary medicine is in general conducted within health care systems. Legal, credentialing and financing frameworks are established by individual governments, augmented on occasion by international organizations, such as churches. The characteristics of any given health care system have significant impact on the way medical care is provided.

From ancient times, Christian emphasis on practical charity gave rise to the development of systematic nursing and hospitals and the Catholic Church today remains the largest non-government provider of medical services in the world. Advanced industrial countries (with the exception of the United States) and many developing countries provide medical services through a system of universal health care that aims to guarantee care for all through a single-payer health care system, or compulsory private or co-operative health insurance. This is intended to ensure that the entire population has access to medical care on the basis of need rather than ability to pay. Delivery may be via private medical practices or by state-owned hospitals and clinics, or by charities, most commonly by a combination of all three.

Most tribal societies provide no guarantee of healthcare for the population as a whole. In such societies, healthcare is available to those that can afford to pay for it or have self-insured it (either directly or as part of an employment contract) or who may be covered by care financed by the government or tribe directly.

collection of glass bottles of different sizes

Modern drug ampoules

Transparency of information is another factor defining a delivery system. Access to information on conditions, treatments, quality, and pricing greatly affects the choice by patients/consumers and, therefore, the incentives of medical professionals. While the US healthcare system has come under fire for lack of openness,[55] new legislation may encourage greater openness. There is a perceived tension between the need for transparency on the one hand and such issues as patient confidentiality and the possible exploitation of information for commercial gain on the other.