Over the years several hypothesis have tried to explain the process of ageing. Here are a few
Genetic hypothesis: Aging is genetic program activated in post reproductive life when an individual’s evolutionary mission is accomplished.
Oxidative Stress Hypothesis: Accumulation of oxidative damage to DNA, proteins, and lipid interferes with normal function and produces a decrease in stress responses.
Mitochondrial dysfunction Hypothesis: A common deletion in mitochondrial DNA with age compromises function and alters cell metabolic processes and adaptability to environmental change.
Hormonal Change Hypothesis: The decline and loss of circardian rhythm in secretion of some hormones produces a functional hormone deficiency state.
Telomere shortening Hypothesis: Aging is related to a decline in the ability of cells to replicate.
Defective host defence hypothesis: The failure of the immune system to respond to infectious agents and the overactivity of natural immunity careate vulnerability to environmental stresses.
Accumulation of senescent cells: Renewing tissues becomes dysfunctional through loss of ability to renew.
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