Health is the general condition of a person in all aspects. It is also a level of functional and/or metabolic efficiency of an organism, often implicitly human.
At the time of the creation of the World Health Organization (WHO), in 1948, health was defined as being "a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity".
Only a handful of publications have focused specifically on the definition of health and its evolution in the first 6 decades. Some of them highlight its lack of operational value and the problem created by use of the word "complete." Others declare the definition, which has not been modified since 1948, "simply a bad one." 
In 1986, the WHO, in the Ottawa Charter for Health Promotion, said that health is "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." Classification systems such as the WHO Family of International Classifications (WHO-FIC), which is composed of the International Classification of Functioning, Disability, and Health (ICF) and the International Classification of Diseases (ICD) also define health.
Overall health is achieved through a combination of physical, mental, emotional, and social well-being, which, together is commonly referred to as the Health Triangle.
Determinants of health
Template:Main The LaLonde report suggests that there are four general determinants of health including human biology, environment, lifestyle, and healthcare services. Thus, 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.
Studies show that in developed countries, the lack of neighborhood recreational space that includes the natural environment leads to lower levels of neighborhood satisfaction and higher levels of obesity; therefore, lower overall well being. Therefore, the positive psychological benefits of natural space in urban neighborhoods should be taken into account in public policy and land use.
Template:Main Achieving and maintaining health is an ongoing process. Effective strategies for staying healthy and improving one's health include the following elements:
Observations of Daily Living 
Personal health depends partially on one's active, passive, and assisted observations about their health in their everyday life. The information gleaned from such observations may be used to inform personal decisions and actions (e.g., "I feel tired in the morning so I am going to try sleeping on a different pillow"), as well as clinical decisions and treatment plans (e.g., a patient who notices his or her shoes are tighter than usual may be having exacerbation of left-sided heart failure, and may require diuretic medication to reduce fluid overload) for patients who share their observations with their health care providers.Template:Citation needed
Template:Main Personal health depends partially on the social structure of one's life. The maintenance of strong social relationships is linked to good health conditions, longevity, productivity, and a positive attitude. This is due to the fact that positive social interaction as viewed by the participant increases many chemical levels in the brain which are linked to personality and intelligence traits.
Volunteering also can lead to a healthy life. To be a volunteer, while gaining plenty of social benefits, people also take their mind off their own troubles.Template:Citation needed Volunteering could even add years of life. According to a university study,Template:Citation needed compared with people who did not volunteer, senior citizens who volunteered showed a 67% reduced risk of dying during a seven-year period.
Hygiene is the practice of keeping the body clean to prevent infection and illness, and the avoidance of contact with infectious agents. Hygiene practices include bathing, brushing and flossing teeth, washing hands especially before eating, washing food before it is eaten, cleaning food preparation utensils and surfaces before and after preparing meals, and many others. This may help prevent infection and illness. By cleaning the body, dead skin cells are washed away with the germs, reducing their chance of entering the body.
Prolonged psychological stress may negatively impact health, and has been cited as a factor in cognitive impairment with aging, depressive illness, and expression of disease.. Stress management is the application of methods to either reduce stress or increase tolerance to stress. Relaxation techniques are physical methods used to relieve stress. Psychological methods include cognitive therapy, meditation, and positive thinking which work by reducing response to stress. Improving relevant skills and abilities builds confidence, which also reduces the stress reaction to situations where those skills are applicable.
Reducing uncertainty, by increasing knowledge and experience related to stress-causing situations, has the same effect. Learning to cope with problems better, such as improving problem solving and time management skills, may also reduce stressful reaction to problems. Repeatedly facing an object of one's fears may also desensitize the fight-or-flight response with respect to that stimulus—e.g., facing bullies may reduce fear of bullies.
Health care  is the prevention, treatment, and management of illness and the preservation of mental and physical well being through the services offered by the medical, nursing, and allied health professions.
Workplace wellness programs
Workplace wellness programs are recognized by an increasingly large number of companies for their value in improving the health and well-being of their employees, and for increasing morale, loyalty, and productivity.Template:Citation needed Workplace wellness programs can include things like onsite fitness centers, health presentations, wellness newsletters, access to health coaching, tobacco cessation programs and training related to nutrition, weight and stress management. Other programs may include health risk assessments, health screenings and body mass index monitoring.
Wellness programs may also be found in such places neighborhood community centers and schools. These typically require participants to have a greater degree of commitment to themselves, as they are voluntary.
Public health is "the science and art of preventing disease, prolonging life and promoting health through the organised efforts and informed choices of society, organizations, public and private, communities and individuals." (Winslow, 1920) Template:Citation needed It is concerned with threats to the overall health of a community based on population health analysis. The population in question can be as small as a handful of people or as large as all the inhabitants of several continents (for instance, in the case of a pandemic). Public health has many sub-fields, but is typically divided into the categories of epidemiology, biostatistics and health services. Environmental, social and behavioral health, and occupational health, are also important fields in public health.
The focus of public health intervention is to prevent rather than treat a disease through surveillance of cases and the promotion of healthy behaviors. In addition to these activities, in many cases treating a disease can be vital to preventing it in others, such as during an outbreak of an infectious disease. Vaccination schedules and distribution of condoms are examples of public health measures.
Role of science in health
Health science is the branch of science focused on health, and it includes many subdisciplines. There are two approaches to health science: the study and research of the human 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.
Health research builds primarily on the basic sciences of biology, chemistry, and physics as well as a variety of multidisciplinary fields (for example medical sociology). Some of the other primarily research-oriented fields that make exceptionally significant contributions to health science are biochemistry, epidemiology, and genetics.
Applied health sciences also endeavor to better understand health, but in addition they try to directly improve it. Some of these are: biomedical engineering, biotechnology, nursing, nutrition, pharmacology, pharmacy, public health (see above), social work, psychology, physical therapy, and medicine. The provision of services to maintain or improve people's health is referred to as health care (see above).
- ↑ WHO.int, Preamble to the Constitution of the World Health Organization as adopted by the International Health Conference, New York, 19–22 June 1946; signed on 22 July 1947 by the representatives of 61 States (Official Records of the World Health Organization, no. 2, p. 100); and entered into force on 7 April 1948.
- ↑ WHO.int Constitution of the World Health Organization- Basic Documents, Forty-fifth edition, Supplement, October 2006.
- ↑ Lalonde, Marc. "A New Perspective on the Health of Canadians." Ottawa: Minister of Supply and Services; 1974.
- ↑ The UN World Water Development Report | Facts and Figures | Meeting basic needs
- ↑ "Recreational Values of the Natural Environment in Relation to Neighborhood Satisfaction, Physical Activity, Obesity and Wellbeing."
- ↑ Health in Everyday Living Robert Wood Johnson Foundation primer
- ↑ Template:Cite journal
- ↑ Template:Cite web
- World Health Organization
- Health On the Net Foundation
- OECD Health Statistics
- 'Defying Death' On-line video on disease (Provided by the Vega Science Trust).
- Health and Medical Information from UCB Libraries GovPubs
- Health-EU Portal the official public health portal of the European Union