Ageing of our body actually starts after 40 years. Generally, our physical strength keeps on increasing from our birth until the age of 25-30 years, then it stays on the peak for about 10 years and then the strength gradually keeps on decreasing until the age that we die. This is ageing.
Ageing is a privilege and social achievement. It is also a challenge, which will influence all aspects of today’s society. It is a challenge that everyone has to face. It is a deterioration of physical capabilities and functions with a decreased viability and increased vulnerability and probability of death.
What causes ageing is exactly not known but there are certain theories to explain ageing process that begins at birth and progresses until death.
♦Ageing takes place as some irreplaceable materials, which a body has at birth, are gradually utilized.
♦Ageing is because of accumulation of what has been termed “the debris of life” which results in eventual clogging of the vital processes of the body.
♦Ageing is the combination of the above two theories.
Further, there are different processes that leads to ageing that are:
♦Limited cell life: Cells in older persons have less potential for population doubling than cells in younger population. The physiologic function begins to decline in many tissues shortly after reproductive part of the life cycle. This decline proceeds at different rates for different tissues.
♦Repair theory: This theory proposes that longevity is determined by the cell’s ability to repair damage that may occur to DNA of the nucleus in the cell. In old age, repair capability of a person decreases.
♦Decreased immunity: Normal defence (Immunity) functions of body begin to decline quite early in life. The changes are because of the changes in immune cells themselves.
♦Decreased hormonal functions: many hormonal functions control the process of ageing and eventual death. Decline in the hormonal function contributes to ageing.
♦Free radical damage: In humans, life span correlates with the average specific metabolic rate. This suggests the products of oxygen metabolism might be influences ageing. The ability to cope up with oxidant stress seems to determine longevity. Damage to DNA may be important in ageing