Actually, aging is a natural process wherein each cells that making us a so called human being undergoes apoptosis (cell death) and that continuously being replaced by new cells. However, during a span of days, months and years wherein an individual has been very susceptible to a lot of harmful agents from the environments, the aging process of the cells becomes faster.
Moreover, with the very technologically up generations we have now, three Aussie-American researchers namely, Elizabeth Blackburn, Carol Greider and Jack Szostak had successfully uncover what makes the cell age faster. Their discovery made them won the 2009 Nobel Prize Winner for Medicine.
More of the story will be posted soon.