Health, as defined by the World Health Organization, is a state of full physical, emotional and social well being and not just the absence of illness and infirmity. A number of definitions have also been used over the years for various purposes. In its most general sense, health is a state of the body in its ability to function normally with a minimum of external support. People in good health are physically fit, mentally alert, and emotionally stable; someone with poor health may be malnourished, stressed, depressed, and isolated. Some other terms that might be used to describe a state of good health are: equilibrium, health, total existence, well-being, happiness, fulfillment, and well-being.

In order to attain the desired state of health and well being, many social determinants contribute to achieving optimum health. These determinants are personal and public health. The personal determinants include behavior, personality, values, cultural practices, social networks, and physiology. The public determinants are society, environment, politics, medical practice, and policies. It is important to note that these determinants do not all come equal, and there is considerable interdependence among them.

There are a number of methods of improving health. For example, some researchers have developed theories of aging and health, aging and life course perspectives, and life course theory, which suggests that different patterns of life and health span are influenced by a number of social and environmental factors. Managing disease is part of healthy living. The challenge is how we can translate health knowledge into public policies that will make it easier for older adults to live fulfilling lives.