"An untrained individual in an overnight fasted state who has a sample of blood collected in the morning from an arm vein before any exercise has a lactate level ranging from about 4-15 mg/dl. We find that our trained elite distance runners typically have a lactate level near the low end of this range (around 3-5 mg/dl) if they are not overtrained. (However, one residual effect of either a very hard single training session or a period of overtraining is a morning postabsorptive lactate level that is either very high normal or clinically elevated.)" -taken from Better Training for Distance Runners by David E. Martin, Ph D, and Peter N. Coe.
My comment: Wouldn't it be nice to have this little test at your disposal, telling you exactly when you are ready for your next hard workout? Is there anything that you can do to reduce blood lactate and speed recovery? Ice baths, compression socks, elevating feet for a short time, cool-down, massage, proper nutrition, and rest immediately following a workout all come to mind.