Ageing

Is the process of becoming older. It represents the accumulation of changes in a person over time. In humans, ageing refers to a multidimensional process of physical,psychological, and social change. Reaction time, for example, may slow with age, while knowledge of world events and wisdom may expand. Ageing is an important part of all human societies reflecting the biological changes that occur, but also reflecting cultural and societal conventions. Ageing is among the largest known risk factors for most human diseases.

At present, the biological basis of ageing is unknown. The rate of ageing varies substantially across different species, and this, to a large extent, is genetically based.