How interesting.
Thanks for those links.
I used to be a night owl, but then everything changed and as it mentioned in that first article,
the "onset and offset of sleep moves earlier by several hours".

I'm waking earlier and earlier. By the time summer arrives, I'll probably be waking at 2 or 3am by the feel of it.

I used to try to get out in the sunlight just after waking up, but then I stopped and this sleep cycle change happened. I might try making a better routine and see if I can move it all forward again. I just thought it was old age.

thanks again.

btw, Some people on the forums use light visors for this reason and there are posts about them if you ever want to search them.