
Ageing is the progressive biological, psychological, physiological, environmental, social and behavioural changes. Some of these age changes are benign, such as greying of hair. At the same time, most of these changes in an organism lead to senescence, a decline in biological functions, and the organism’s ability to adapt to different metabolic stresses. In short, ageing is a gradual, continuous process of natural change that begins in early adulthood.