I met Steve in the mid 80's (ran with his coach) and he is just the nicest guy. And funny too.
I remember watching him place in the Pittsburgh Marathon one year (didn't win but good prize money) and the first thing he said was something like "Get to keep the Bmer for another year!". Great guy.
Big props to him for all he's done.
I'm 52 and I haven't missed a week of exercise since I was 14. I'm fit. Not running fit but pretty fit given that I weigh 210lbs and row more than I run. I ran 3.5mi in 6:05 pace after a few months of intervals and 3-4 days a week running w some cross training thrown in. So my point is that you can run 6-7min pace for reasonably long periods for a long time. BUT RUNNING FAST IS VERY HARD AS A 50YR OLD. When I did the intervals I'd swear I was running 65sec quarter pace and I was running 73-74. I can't see myself run so you go on effort and since speed/reaction etc...go way before strength and endurance your body is tricked into thinking you are running much faster. Believe me guys...5min pace at 50 is very fast. So try to enjoy your speed workouts while you can still do them at a respectable pace!!