At the time of the creation of the World Health Organization (WHO), in 1948, health was defined as “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 theInternational Classification of Diseases (ICD) also define health.
Overall health is achieved through a combination of physical, mental, and social well-being, which, together is commonly referred to as the Health Triangle.
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.
The Alameda County Study examines the relationship between lifestyle and health. It has found that people can improve their health via exercise, enough sleep, maintaining a healthyweight, limiting alcohol use, and avoiding smoking.
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.
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. Generally, the context in which an individual lives is of great importance on his life quality and health status. The social and economic environment are key factors in determining the health status of individuals given the fact that higher education levels are linked with a higher standard of life as well as a higher income. Generally, people who finish higher education are more likely to get a better job and therefore are less prone to stress by comparing to individuals with low education levels.
The physical environment is perhaps the most important factor that should be considered when classifying the health status of an individual. This includes factors such as clean waterand air, safe houses, communities and roads all contribute to good health.
Genetics are also part of the system based on which the health of the population can be established. Genetics are closely related to the habits and behaviors individuals develop during their life, particularly in terms of lifestyle choices. For instance, people who come from families whose members had a more active lifestyle and followed healthier diets, non-smoking and non-drinking are more likely to follow the same pattern in their life. The example set by the family as well as the relationship with friends and family can have a great impact on one’s general health. Nonetheless, genetics may play a role in the manner in which people cope with stress.
Moreover, the World Health Organization lists a wide range of other factors that can influence the well being of a person. According to WHO, the gender, social support networks and health services in terms of both quality and access to them are to be considered as health determinants. Access to health care is one of the large issues of the nowadays society, maybe even greater than the quality of the service. Individuals in developing countries are more prone to suffer from different health conditions because their access to the health care system is restricted mostly from financial reasons.
Although many individuals are often criticized for not taking good care of their health based on the presumption that the mirror‘s of one’s personality is one’s health., it is now accepted that there are many factors that have a significant impact on one’s health and which cannot be controlled.