Quote Originally Posted by Ne-yo View Post
I understand the biological process of why we age but the topping out part is what I don't get.
The biological process is what causes topping out. If telomeres get shorter with every replication, there must be a point were telomeres are depleted and cells can not longer divide. In a way, your maximal lifespan is determined by the lengths of telomeres at the moment of your birth, it must have some upper bound.

Personally, I find the theory of telomere lenght as the main reason for ageing and dying of old age unsatisfactory, but it's the best theory we have at this point.