What do you mean when you say 'a healthy elderly"? Does it mean an elderly without any illness? But is it fair to say that an elderly who has hypertension unhealthy? According WHO, health is "a state of complete physical, mental and social well being and not merely the absence of diseases and infirmity". This definition was updated fifty years later with the addition of two words, "Health is a dynamic state of complete physical, mental, spiritual and social well-being and not merely the absence of disease or infirmity".
With the addition of the word spiritual, it indicates the influence of values, beliefs, norms and practices. This led to debates on what is health and summarizing the different definitions, we can say that health is a multifaceted phenomenon (Aggleton, 1990). It is a multi-faceted entity.
Another way of looking at it is to look at it as positive or negative approach. Positive meaning health being viewed as a capacity or an asset to be possessed. Negative approach means taking the approach of absence of specific illnesses, diseases or disorders.
Hence, health in my PhD was viewed as, "The capacity and asset to be possessed, which would enable one to function and involve in one's environment in a manner acceptable to himself and or herself and to the community he or she is part, without living in fear of illness and the presence or absence of diseases is only part of life".