I think that for me to work on my Lactic acid threshhold I could conceivably get to or over my MHR. So much cycling training is done at 70% MHR. This is a range for most people where they build up their efficiency of aerobic exercise. that's why it is important to do the build a base workouts when you start. It helps the mitochondria become more efficient at their job.

I know in running, Lactic Threshold is a different animal or so I"m told by some runner friends.

Kim