Health, as defined by the World Health Organization, is a condition of full physical, emotional and social well being and not just the absence of illness and infirmity. Different definitions have been applied for various purposes over the years. A healthy body is generally viewed to mean having strong muscles and bones, being in good mental and emotional health, and having a balanced diet. Health and nutrition are included in this definition. While these are important elements of a healthy lifestyle, there are also other aspects that are equally important, and can contribute to a healthy lifestyle.

A definition that covers prevention, early detection and treatment is known as the public health approach. According to this definition, a public health policy is designed to promote the prevention of diseases, improve the availability of health services, and keep the population healthy through a program of public health interventions, programs, policies, and institutions. This definition excludes circumstances such as accidents, occupational hazards, and certain infectious diseases.

The social definition maintains that “health” refers to a person’s ability to live his or her life comfortably. It also emphasizes the fact that life course diseases like cancer, AIDS, and diabetes are diseases of the life course. These diseases usually develop in people during their old age. Therefore, a life course disease is also not an illness and must not be classed as an illness.

On the other hand, absence defined health is the lack of any serious disease, illness, or injury that does not occur until a later age. According to this definition, illnesses and deaths caused by diseases cannot be classed as absent because the victim may still be able to lead his or her life. However, there is a difference between absence and life course absence.

According to the third definition, absence is when a person dies before attaining a certain age. Some of the diseases of the third definition are all-cause mortality, which means that death caused by a disease occurs without a reason or an event that causes the death. A cause associated with a disease cannot be excluded as a cause of death for some individuals if it is known that the disease was acquired through some negligence or accident. On the other hand, death that is caused by an illness can be excluded. This is so because illness is generally not a cause of death.

Most definitions maintain that good health is subjective. This means that what is good for one person is not necessarily good for another. Thus, health is a relational concept rather than a scientific one. As a result, health is affected by culture, social patterns, and experiences. Some diseases of the third definition are caused by external factors while others are internal. Hence, how to have a good health depends on the way society perceives health.