Difficulty Staying Asleep

I wonder if it is a function of rapidly approaching forty? I tend to sink into sleep earlier and earlier each evening, particularly if I'm parked on the couch in front of the television. But then after only six hours of sleep or so, my mind starts humming at 5:30 or 6:00 a.m., and it actually becomes physically uncomfortable to stay in bed. If I don't get up and get moving with my day, my mind will spin ever widening circles of pointless mania until I finally give in to it and get up so I can distract myself with minutiae. So I came to the desk and began updating and formatting this blog. What's even worse is that today is Saturday. How absurd. I should be sleeping until 10 a.m. or even later. I remember how in college I could sleep until 1:30 p.m. without even stirring from bedtime the night before. It's a bit depressing. I've already been up for an hour and there's not even a trace of sunrise yet.