Health, as defined by the World Health Organization (WHO), is "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity." This definition has been subject to controversy, as it may have limited value for implementation. Health may be defined as the ability to adapt and manage physical, mental and social challenges throughout life.
Selected general articles
is the maintenance or improvement of health
via the prevention
, and treatment
, and other physical and mental impairments
in human beings. Health care is delivered by health professionals
(providers or practitioners) in allied health fields
and physician associates are a part of these health professionals. Dentistry
, occupational therapy
, physical therapy
and other health professions
are all part of health care. It includes work done in providing primary care
, secondary care
, and tertiary care
, as well as in public health
Access to health care may vary across countries, communities, and individuals, largely influenced by social and economic conditions as well as the health policies
in place. Countries and jurisdictions have different policies and plans in relation to the personal and population-based health care goals within their societies. Health care systems
are organizations established to meet the health needs of targeted populations. Their exact configuration varies between national and subnational entities. In some countries and jurisdictions, health care planning is distributed among market participants, whereas in others, planning occurs more centrally among governments or other coordinating bodies. In all cases, according to the World Health Organization
(WHO), a well-functioning health care system requires a robust financing mechanism; a well-trained and adequately paid workforce
; reliable information on which to base decisions and policies
; and well maintained health facilities
and logistics to deliver quality medicines and technologies.
Health care can contribute to a significant part of a country's economy
. In 2011, the health care industry
consumed an average of 9.3 percent of the GDP
) per capita across the 34 members of OECD
countries. The US (17.7%, or US$ PPP 8,508), the Netherlands
(11.9%, 5,099), France
(11.6%, 4,118), Germany
(11.3%, 4,495), Canada
(11.2%, 5669), and Switzerland
(11%, 5,634) were the top spenders, however life expectancy in total population at birth
was highest in Switzerland (82.8 years), Japan
(82.4), France (82.2) and Australia
(82.0), while OECD's average exceeds 80 years for the first time ever in 2011: 80.1 years, a gain of 10 years since 1970. The US (78.7 years) ranges only on place 26 among the 34 OECD member countries, but has the highest costs by far. All OECD countries have achieved universal (or almost universal) health coverage, except the US and Mexico
. (see also international comparisons
.) Read more...
is the study and analysis of the distribution (who, when, and where) and determinants
of health and disease conditions in defined populations
It is the cornerstone of public health
, and shapes policy decisions and evidence-based practice
by identifying risk factors
for disease and targets for preventive healthcare
. Epidemiologists help with study design, collection, and statistical analysis
of data, amend interpretation and dissemination of results (including peer review
and occasional systematic review
). Epidemiology has helped develop methodology
used in clinical research
, public health
studies, and, to a lesser extent, basic research
in the biological sciences.
Major areas of epidemiological study include disease causation, transmission
investigation, disease surveillance
, environmental epidemiology
, forensic epidemiology
, occupational epidemiology
, and comparisons of treatment effects such as in clinical trials
. Epidemiologists rely on other scientific disciplines like biology
to better understand disease processes, statistics
to make efficient use of the data and draw appropriate conclusions, social sciences
to better understand proximate and distal causes, and engineering
for exposure assessment
. Read more...
(alternately preventive medicine, preventative healthcare/medicine,
) consists of measures taken for disease prevention, as opposed to disease treatment. Just as health
comprises a variety of physical and mental states, so do disease and disability, which are affected by environmental factors
, genetic predisposition
, disease agents, and lifestyle choices. Health, disease, and disability are dynamic processes which begin before individuals realize they are affected. Disease prevention relies on anticipatory actions that can be categorized as primal, primary, secondary, and tertiary prevention.
Each year, millions of people die of preventable deaths. A 2004 study showed that about half of all deaths in the United States in 2000 were due to preventable behaviors and exposures. Leading causes included cardiovascular disease
, chronic respiratory disease
, unintentional injuries, diabetes
, and certain infectious diseases. This same study estimates that 400,000 people die each year in the United States due to poor diet and a sedentary lifestyle
. According to estimates made by the World Health Organization
(WHO), about 55 million people died worldwide in 2011, two thirds of this group from non-communicable diseases, including cancer
, and chronic cardiovascular
and lung diseases
. This is an increase from the year 2000, during which 60% of deaths were attributed to these diseases. Preventive healthcare is especially important given the worldwide rise in prevalence of chronic diseases and deaths from these diseases.
There are many methods for prevention of disease. It is recommended that adults and children aim to visit their doctor for regular check-ups, even if they feel healthy, to perform disease screening
, identify risk factors for disease, discuss tips for a healthy and balanced lifestyle, stay up to date with immunizations and boosters, and maintain a good relationship with a healthcare provider. Some common disease screenings include checking for hypertension
(high blood pressure), hyperglycemia
(high blood sugar, a risk factor for diabetes mellitus
(high blood cholesterol), screening for colon cancer
and other common types of sexually transmitted disease
such as chlamydia
, and gonorrhea
(to screen for breast cancer
), colorectal cancer
screening, a Pap test
(to check for cervical cancer
), and screening for osteoporosis
. Genetic testing can also be performed to screen for mutations that cause genetic disorders
or predisposition to certain diseases such as breast or ovarian cancer
. However, these measures are not affordable for every individual and the cost effectiveness of preventive healthcare is still a topic of debate. Read more...
, also spelled haematology
, is the branch of medicine
concerned with the study of the cause, prognosis, treatment, and prevention of diseases related to blood
. It involves treating diseases that affect the production of blood and its components, such as blood cells
, blood proteins
, bone marrow
, blood vessels
, and the mechanism of coagulation
. Such diseases might include hemophilia
, blood clots, other bleeding disorders and blood cancers
such as leukemia
, multiple myeloma
, and lymphoma
. The laboratory work that goes into the study of blood is frequently performed by a medical technologist
or medical laboratory scientist
. Many hematologists work as hematologist-oncologists, also providing medical treatment for all types of cancer. The term is from the Greek αἷμα
meaning "blood," and -λoγία
meaning study. Read more...
, also known as Dental and Oral Medicine
, is a branch of medicine
that consists of the study, diagnosis
, prevention, and treatment of diseases
, disorders, and conditions of the oral cavity
, commonly in the dentition
but also the oral mucosa
, and of adjacent and related structures and tissues, particularly in the maxillofacial (jaw and facial) area. Although primarily associated with teeth
among the general public, the field of dentistry or dental medicine is not limited to teeth but includes other aspects of the craniofacial
complex including the temporomandibular joint
and other supporting, muscular, lymphatic, nervous, vascular, and anatomical structures.
Dentistry is often also understood to subsume the now largely defunct medical specialty
(the study of the mouth and its disorders and diseases) for which reason the two terms are used interchangeably in certain regions.
Dental treatments are carried out by a dental team, which often consists of a dentist
and dental auxiliaries
, dental hygienists
, dental technicians
, as well as dental therapists
). Most dentists either work in private practices (primary care
), dental hospitals or (secondary care
) institutions (prisons, armed forces bases, etc.). Read more...
In the context of nutrition, a mineral
is a chemical element
required as an essential nutrient
to perform functions necessary for life. However, the four major structural elements in the human body by weight (oxygen, hydrogen, carbon, and nitrogen), are usually not included in lists of major nutrient minerals (nitrogen is considered a "mineral" for plants, as it often is included in fertilizers). These four elements compose about 96% of the weight of the human body, and major minerals (macrominerals) and minor minerals (also called trace elements) compose the remainder.
Minerals, as elements, cannot be synthesized biochemically by living organisms. Plants get minerals from soil
. Most of the minerals in a human diet come from eating plants and animals or from drinking water. As a group, minerals
are one of the four groups of essential nutrients, the others of which are vitamins
, essential fatty acids
, and essential amino acids
. The five major minerals in the human body
, and magnesium
. All of the remaining elements in a human body are called "trace elements". The trace elements that have a specific biochemical function in the human body are sulfur
Most chemical elements
that are ingested
by organisms are in the form of simple compounds. Plants absorb dissolved elements in soils, which are subsequently ingested by the herbivores
that eat them, and the elements move up the food chain
. Larger organisms may also consume soil (geophagia
) or use mineral resources, such as salt licks
, to obtain limited minerals unavailable through other dietary sources. Read more...
occurs when a person exceeds their body's ability to recover from strenuous exercise
. Overtraining can be described as a point where a person may have a decrease in performance and plateauing as a result of failure to consistently perform at a certain level or training load; a load which exceeds their recovery capacity. People who are overtrained cease making progress, and can even begin to lose strength
. Overtraining is also known as chronic fatigue, burnout and overstress in athletes. It is suggested that there are different variations of overtraining, firstly monotonous program over training suggest that repetition of the same movement such as certain weight lifting and baseball batting can cause performance plateau due to an adaption of the central nervous system which results from a lack of stimulation. A second example of overtraining is described as chronic overwork type training where the subject may be training with too high intensity or high volume and not allowing sufficient recovery time for the body. Up to 10% of elite endurance athletes and 10% of American college swimmers are affected by overtraining syndrome (unexplained underperformance for approximately 2 weeks even after having adequate resting time). Read more...
is the idea of extending the human lifespan
, either modestly – through improvements in medicine – or dramatically by increasing the maximum lifespan
beyond its generally settled limit of 125 years
. The ability to achieve such dramatic changes, however, does not currently exist.
Some researchers in this area, and "life extensionists", "immortalists" or "longevists" (those who wish to achieve longer lives themselves), believe that future breakthroughs in tissue rejuvenation
, stem cells
, regenerative medicine
repair, gene therapy
, pharmaceuticals, and organ
replacement (such as with artificial organs or xenotransplantations
) will eventually enable humans to have indefinite lifespans (agerasia) through complete rejuvenation to a healthy youthful condition. The ethical ramifications, if life extension becomes a possibility, are debated by bioethicists
The sale of purported anti-aging products such as supplements and hormone replacement is a lucrative global industry. For example, the industry that promotes the use of hormones as a treatment for consumers to slow or reverse the aging process in the US market generated about $50 billion of revenue a year in 2009. The use of such products has not been proven to be effective or safe. Read more...
A selection of plant-sourced food
consumed by humans. The human diet can vary widely.
is the sum of food consumed by a person or other organism
The word diet often implies the use of specific intake of nutrition
reasons (with the two often being related). Although humans are omnivores
, each culture and each person holds some food preferences or some food taboos. This may be due to personal tastes or ethical reasons. Individual dietary choices may be more or less healthy.
Complete nutrition requires ingestion and absorption of vitamins
, essential amino acids from protein and essential fatty acids from fat-containing food, also food energy
in the form of carbohydrate, protein, and fat. Dietary habits and choices play a significant role in the quality of life
. Read more...
: smart drugs
and cognitive enhancers
) are drugs
, and other substances that may improve cognitive function
, particularly executive functions
, memory, creativity, or motivation
, in healthy individuals. While many substances are purported to improve cognition, research is at a preliminary stage as of 2018, and the effects of the majority of these agents are not fully determined.
The use of cognition-enhancing drugs by healthy individuals in the absence of a medical indication
spans numerous controversial issues, including the ethics
and fairness of their use, concerns over adverse effects
, and the diversion
of prescription drugs
for nonmedical uses, among others. Nonetheless, the international sales of cognition-enhancing supplements exceeded US$
1 billion in 2015 when global demand for these compounds grew.
The word nootropic
was coined in 1972 by a Romanian psychologist and chemist, Corneliu E. Giurgea
, from the Greek
words νοῦς (nous
), or "mind", and τρέπειν (trepein
), meaning to bend or turn. Read more...
is a condition that results from eating a diet
in which one or more nutrients
are either not enough or are too much such that the diet causes health problems. It may involve calories
. Not enough nutrients is called undernutrition
while too much is called overnutrition
. Malnutrition is often used to specifically refer to undernutrition where an individual is not getting enough calories, protein, or micronutrients
. If undernutrition occurs during pregnancy
, or before two years of age, it may result in permanent problems with physical and mental development. Extreme undernourishment, known as starvation
, may have symptoms that include: a short height, thin body, very poor energy levels, and swollen legs and abdomen
. People also often get infections and are frequently cold
. The symptoms of micronutrient deficiencies
depend on the micronutrient that is lacking.
Undernourishment is most often due to not enough high-quality food being available to eat. This is often related to high food prices and poverty
. A lack of breastfeeding
may contribute, as may a number of infectious diseases
such as: gastroenteritis
, and measles
, which increase nutrient requirements. There are two main types of undernutrition: protein-energy malnutrition
and dietary deficiencies. Protein-energy malnutrition has two severe forms: marasmus
(a lack of protein and calories) and kwashiorkor
(a lack of just protein). Common micronutrient deficiencies include: a lack of iron
, and vitamin A
. During pregnancy
, due to the body's increased need, deficiencies may become more common. In some developing countries
, overnutrition in the form of obesity
is beginning to present within the same communities as undernutrition. Other causes of malnutrition include anorexia nervosa
and bariatric surgery
Efforts to improve nutrition
are some of the most effective forms of development aid
. Breastfeeding can reduce rates of malnutrition and death in children, and efforts to promote the practice increase the rates of breastfeeding. In young children, providing food (in addition to breastmilk) between six months and two years of age improves outcomes. There is also good evidence supporting the supplementation
of a number of micronutrients to women during pregnancy and among young children in the developing world. To get food to people who need it most, both delivering food and providing money so people can buy food within local markets are effective. Simply feeding students at school is insufficient. Management of severe malnutrition within the person's home with ready-to-use therapeutic foods
is possible much of the time. In those who have severe malnutrition complicated by other health problems, treatment in a hospital setting is recommended. This often involves managing low blood sugar
and body temperature
, addressing dehydration
, and gradual feeding. Routine antibiotics
are usually recommended due to the high risk of infection. Longer-term measures include: improving agricultural practices, reducing poverty, improving sanitation
, and the empowerment of women
. Read more...
, also known as alcohol use disorder
), is a broad term for any drinking of alcohol
that results in mental
or physical health
problems. The disorder was previously divided into two types: alcohol abuse
and alcohol dependence
. In a medical context, alcoholism is said to exist when two or more of the following conditions are present: a person drinks large amounts over a long time period, has difficulty cutting down, acquiring and drinking alcohol takes up a great deal of time, alcohol is strongly desired, usage results in not fulfilling responsibilities, usage results in social problems, usage results in health problems, usage results in risky situations, withdrawal
occurs when stopping, and alcohol tolerance
has occurred with use. Risky situations include drinking and driving
or having unsafe sex
, among other things. Alcohol use can affect all parts of the body, but it particularly affects the brain, heart, liver, pancreas
and immune system
. This can result in mental illness
, Wernicke–Korsakoff syndrome
, irregular heartbeat
, liver cirrhosis
and increased cancer risk
, among other diseases. Drinking during pregnancy
can cause damage to the baby resulting in fetal alcohol spectrum disorders
. Women are generally more sensitive than men to the harmful physical and mental effects of alcohol.
Environmental factors and genetics are two components associated with alcoholism, with about half the risk attributed to each. Someone with a parent or sibling with alcoholism is three to four times more likely to become an alcoholic themselves. Environmental factors include social, cultural and behavioral influences. High stress levels
and anxiety, as well as alcohol's inexpensive cost and easy accessibility, increase the risk. People may continue to drink partly to prevent or improve symptoms of withdrawal. After a person stops drinking alcohol, they may experience a low level of withdrawal lasting for months. Medically, alcoholism is considered both a physical and mental illness. Questionnaires and certain blood tests
may both detect people with possible alcoholism. Further information is then collected to confirm the diagnosis.
Prevention of alcoholism may be attempted by regulating and limiting the sale of alcohol, taxing alcohol
to increase its cost, and providing inexpensive treatment. Treatment may take several steps. Due to medical problems that can occur during withdrawal, alcohol detoxification
should be carefully controlled. One common method involves the use of benzodiazepine
medications, such as diazepam
. These can be either given while admitted to a health care institution or occasionally while a person remains in the community with close supervision. Mental illness or other addictions
may complicate treatment. After detoxification, support such as group therapy
or support groups
are used to help keep a person from returning to drinking. One commonly used form of support is the group Alcoholics Anonymous
. The medications acamprosate
may also be used to help prevent further drinking. Read more...
Did you know...
- ... that in animal studies of the health and safety hazards of nanomaterials, carbon nanotubes had similar inhalation exposure effects to asbestos?
- ... that the 2011 Löfstedt Report proposed to exempt many British self-employed people from health and safety regulations?
- ... that when introducing actress Sharon Stone, Pulitzer Prize-winning journalist Monroe Karmin attributed her "wellness, fitness, and positive attitude" to her choice of undergarments?
- ... that Luke Fildes' painting The Doctor was used to promote state-run healthcare in Britain and to campaign against it in the United States?
- ... that Alice and Alastair MacLennan, both experts in reproductive health, were caught by surprise and had to deliver their own baby at home?
- ... that the initiation ceremonies for Japan's blind necromancers, known as itako, involve "sleeplessness, semi-starvation and intense cold"?
Do you have a question about Health that you can't find the answer to?
Consider asking it at the Wikipedia reference desk.
For editor resources and to collaborate with other editors on improving Wikipedia's Health-related articles, see WikiProject Health.
Proteins are chains of amino acids found in most nutritional foods.
A bottle of B-complex vitamin pills
Running has become a popular form of exercise.
Roper's gymnasium, Philadelphia, circa 1831.
Colorful fruits and vegetables may be components of a healthy diet.
A lady washing her hands c. 1655
Percentage of overweight or obese population in 2010, Data source: OECD's iLibrary.
James Lind conducted in 1747 the first controlled clinical trial in modern times, and in 1753 published Treatise on Scurvy.
A woman jogging at a beach in the U.S. to maintain/improve her physical fitness
Jack Drummond’s single-paragraph article in 1920 which provided structure and nomenclature used today for vitamins
Postage stamp, New Zealand, 1933. Public health has been promoted – and depicted – in a wide variety of ways.
An astronaut, Daniel Tani, working out with a short bar to increase his upper body strength while in a microgravity environment
Percentage of obese population in 2010, Data source: OECD's iLibrary.
Followed for a millennium and a half, Galen (1st century) created the first coherent (although mistaken) theory of nutrition.
Summary of long-term adaptations to regular aerobic and anaerobic exercise. Aerobic exercise can cause several central cardiovascular adaptations, including an increase in stroke volume (SV) and maximal aerobic capacity (VO2 max), as well as a decrease in resting heart rate (RHR). Long-term adaptations to resistance training, the most common form of anaerobic exercise, include muscular hypertrophy, an increase in the physiological cross-sectional area (PCSA) of muscle(s), and an increase in neural drive, both of which lead to increased muscular strength. Neural adaptations begin more quickly and plateau prior to the hypertrophic response.
Swimmers perform squats prior to entering the pool in a U.S. military base, 2011.
Hippocrates lived about 400 BC, and Galen and the understanding of nutrition followed him for centuries.
Calcium combined with vitamin D (as calciferol) supplement tablets with fillers.
In the news
- See also: Biology (below)
Health – Health is a state of complete physical, mental and social well-being. this is a level of functional and (or) metabolic efficiency of a person in mind, body and spirit; being free from illness, injury or pain (as in “good health” or “healthy”). The World Health Organization (WHO) defined health in its broader sense in 1946 as "a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity."
- Death – cessation of life.
- Exercise – any bodily activity that enhances or maintains physical fitness and overall health and wellness. It is performed for various reasons including strengthening muscles and the cardiovascular system, honing athletic skills, weight loss or maintenance, and mental health including the prevention of depression. Frequent and regular physical exercise boosts the immune system, and helps prevent the "diseases of affluence" such as heart disease, cardiovascular disease, Type 2 diabetes mellitus and obesity.
- Nutrition – provision, to cells and organisms, of the materials necessary (in the form of food) to support life.
- Life extension – The study of slowing down or reversing the processes of aging to extend both the maximum and average lifespan.
- Health sciences – applied sciences that address the use of science, technology, engineering or mathematics in the delivery of healthcare to human beings.
- Medicine – science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness.
- Anesthesia – a way to control pain during a surgery or procedure by using medicine called anesthetics.
- Cardiology – branch of medicine dealing with disorders of the human heart. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease and electrophysiology.
- Clinical research – aspect of biomedical research that addresses the assessment of new pharmaceutical and biological drugs, medical devices and vaccines in humans.
- Diabetes – a group of metabolic diseases in which the person has high blood glucose (blood sugar) above 200mg/dl, either because insulin production is inadequate, or because the body's cells do not respond properly to insulin, or both.
- Dentistry – branch of medicine that is involved in the study, diagnosis, prevention, and treatment of diseases, disorders and conditions of the mouth, maxillofacial area and the adjacent and associated structures (teeth) and their impact on the human body.
- Emergency medicine – medical specialty involving care for undifferentiated, unscheduled patients with acute illnesses or injuries that require immediate medical attention. Emergency physicians undertake acute investigations and interventions to resuscitate and stabilize patients.
- Obstetrics – medical specialty dealing with the care of all women's reproductive tracts and their children during pregnancy (prenatal period), childbirth and the postnatal period.
- Trauma and Orthopedics – medical specialty dealing with bones, joints and operative management of trauma.
- Psychiatry – medical specialty devoted to the study and treatment of mental disorders. These mental disorders include various affective, behavioural, cognitive and perceptual abnormalities.
- Autism a mental condition, present from early childhood, characterized by great difficulty in communicating and forming relationships with other people and in using language and abstract concepts.
- Psychiatric survivors movement – is a diverse association of individuals who either currently access mental health services (known as consumers or service users), or who are survivors of interventions by psychiatry, or who are ex-patients of mental health.