The appropriate definition of aging is likely many different things to many different people.
But in my experience, this idea universal.
For as we age, we talk more and more about our ailments.
If I had to guess, this is a combination of fewer day-to-day (normal) activities, an increase in time spent at the doctor, and a desire to still have something to talk about.
For more on aging, read: Measure Of My Days, By: Florida Scott-Maxwell.
The only objective definition of aging is when a person starts to talk about aging.
-Nassim Taleb, The Bed Of Procrustes