Theories of Aging: Why and How we age

There are many theories on aging. For example the evolutionary theory of aging supposes that genes are inherited that limit the lifespan amongst other things. Further, the theory suggests that some genes that may be beneficial in youth may have negative consequences later in life. This theory suggests that aging is a byproduct of Darwin’s evolutional theory of natural selection. Unlike biology based theories that view aging as a consequence of chemical processes like oxidative stress and hormone losses.

One theory of aging called the theory of programmed death offers the idea that soma cells are predetermined to only split so many times. This idea postulated by Hayflick (1980) and others suggests that once that number has been reached the cell dies. It goes on to explain that in the early stages of cell division (infancy and childhood) the cell divides rapidly and as the individual ages cell division slows down and eventually quits altogether.

Biological based theories of aging include the idea that free radicals cause the body to deteriorate and as a result signs of aging appear. Free radicals can cause accumulated damage to cells and organs that leads to inflammation and further destruction.

Another theory suggests that it is accumulated waste matter that forces aging on people. Included in this body of biological rather than evolutionary theories of aging is the metabolism theory of aging.

There is another theory of aging that metabolism is responsible for the aging process. Delayed or slower metabolism equates to longer life. The energy consumption hypothesis says that burning calories increases damage to cells and results in more rapid aging. In line with this thinking is a theory that suggests severely restricting calorie intake can prolong life and slow down the progression of age related symptoms. Studies with lab animals supports this idea however, few if any longitudal studies have been done with humans and the lab animals received exacting diets high in nutrients. This strategy may be difficult to replicate with humans.

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