As I have grown ancient older, I've found some differences in my life.
Oh there are the obvious things like doctor visits and eyeglasses and various other devices to prolong my span of years.
But I was thinking of my sleep cycle.
When I was younger I stayed awake until late at night, either carousing with friends or reading a book that kept me in thrall.
And I could sleep half the day if my schedule allowed it.
(It usually didn't, which accounts for the lines in my face.)
But now in my dotage Golden Years, I find the arms of Morpheus taking hold earlier and earlier.
Some times there is a wakeful period in the middle of the night and sometimes I sleep through the dark hours.
But frequently I find myself waking and rising for the day at around 6 a.m.
When this first started I found it unusual.