There are two main theories to biological aging, They are known as Primary aging and Secondary Aging. Primary
Aging is also known as Intrinsic Aging and is the aging caused by biological processes which cause physical declines.
There are several theories to why primary aging occurs. There will be 2 discussed in this article. The first is Aging
at the DNA level in the cells. This is thought to a pre-programmed or genetics controls our destiny theory. When and how fast
we age is pre-controlled by our DNA, therefore longevity is a genetic trait. The fact of the matter is that cell duplication
seems to be genetically programmed, or actually genetically doomed. Every time a cell divides it makes a copy of it's DNA
for the new cell. Unfortunately no copy is ever perfect, and eventually the copy of the DNA is not viable. The current research
suggests that a human cell can divide about 50 times +/- 10 times. There have been some research into re-invigorating cell
DNA which has shown promise in extending the lifespan of human cells. The second theory of Primary Aging is that of Cumulative
Effects of Random Events. Cell damage is inevitable in this modern world this damage does happen and is very slow to repair
itself. One theory of why this cell damage takes so long to repair is the gradual slowing of human growth horomone which begins
to slow in the 20's. This growth horomone is what regulates metabolism, enhances cell communication, and repairs the cells,
etc. etc. Another way that cells are damaged is by a chemical process known as free radicals. These strong chemical reactions
damage DNA and create chaos in the cells. The overall cell damage that is not repaired over time weakens organ systems, organ
reserves (also known as the second wind) slows metabolism, and creates problems in homeostasis of the body, or its ability
to bounce back and rebalance itself. Primary aging is most probably caused by a mixture of these 2 theories and not specifically
one or the other.
Secondary Aging is also known as Extrinsic Aging. This is aging cause by environmental or disease processes
that speeds up the actual aging process. It becomes more influential over time due to weakened organ systems and cellular
functioning. Everyone has probably seen this in a relative or friend that gets sick and seems to age in front of you. Or that
lady from Beverly Hills that suntans everyday and gets that leathery skin look by the time she is 40.
For more information on primary and secondary aging click here
All information in this Article came from Notes from 10-15-04 Psych 303 Adult Development and Aging. Taught by Dr. Gary
Creasey PhD. Illinois State University.
This article contributed by Ben Clyde