10 mile tempo run.

This morning I got an early start on my 10 mile tempo run, out the door at a little after 5am.  Yesterday I read a couple of articles from Runner'sWorld.com about the importance of tempo runs and how to do them properly.  I don't think I fully understood, even from what I read in the book Run Less, Run Faster, why tempo runs are an important part of training and how to do them properly for the most benefit.  Tempo runs teach the body how to use oxygen for metabolism more efficiently by increasing the lactate threshold, and over distances, if you do longer tempo runs.

What I understood was that I should be using the first mile of the run as a warm up, to be run at a comfortable pace, then the middle miles of the run should be run at a faster pace, about 15-20 seconds slower than 10K pace (comfortably hard), then the last mile back to a comfortable pace for a cool down.  For me that means, I guess, my goal pace for the "fast" part of the tempo run should be around 11 min./mile.  On today's run I averaged a pace of 11:03 min./mile, so I was right on target.  Here's an excerpt from an article I read in Runner's World:
"Studies indicate that the best predictor of distance-running performance is your lactate threshold, which is the speed you are able to run before lactic acid begins to accumulate in the blood. By regularly including tempo runs in your training schedule, you will increase the speed that you can run before lactic acid begins to slow you down. To use a car analogy, tempo runs will allow your engine to rev faster without red-lining. Before tempo training, you may have red-lined at an 8-minute-per-mile pace. After a few months of tempo runs, you won't red-line until you reach a 7:30-per-mile pace."


I'm still not sure I'm doing the tempo run exactly right, but I hope I am and I hope it helps me.  I really want to improve on my marathon time, without feeling like I'm killing myself - living, breathing, eating, dreaming - running!