Health is said to be the absence of disease. Many others seems to have other definition for the term "health".
In 1948,WHO took a more holistic view of health. They stated that health is a state of complete physical, mental and social well being and not merely the absence of disease or infirmity.
The definition highlights the fact that individuals has functioning physical, psychological and social aspects and it conveys the idea of a person. So in other words, dynamism must be maintained in adapting to the changes in the environment. Apart from the physical factors(disease, vectors), other behavioral factors affect the health of an individual.
Psychology, the mind-body interaction affects health both positively and negatively. Emotional response to stress can change bodily function. Example : worry can make someone to be a chain smoker. Prolonged emotional distress may weaken one's defense and make him susceptible to organic disease or precipitate it;emotional distress may affect the immune system through the central nervous system and endocrine alterations leading to infection, cancer and auto immune diseases.
The way one feels about self, perceives the physical self needs, needs, roles and abilities influence how people view and handle situations and these(attitudes) can affect health practices,response to stress and illness and the times when treatment is sought. Self perception is also associated with a person's definition of health