Smilie redid my lactate threshold test to determine my optimal training range. The test is based on finding the heart rate limit at which the body can no longer absorb the lactate output produced to garner a given level of wattage. A rough metric is that the body can process up to 2.x the normal level of lactate observed at a resting level. Anything beyond that builds up as lactic acid -- which makes the legs feel like rubber -- and makes it impossible to recover day-in and day-out over a long period of time like my stage race. An upper lactate threshold relates to the anaerobic threshold (appx 4.x normal lactate levels) at which the body can maintain performance just below blowing up -- but this level can be held for only an hour -- and is more meaningful for events like time trials and one-day road races.
The good news is that my lower threshold level has been pushed out in terms of wattage and heart rate levels -- meaning I can go faster for longer periods of time at a higher maintainable heart rate. But the bad news is that my top end is not particularly robust -- when I exceed it, I blow pretty much big time. I've let that lapse while training for the longer events like the TransAlp and CapeEpic....but will need to recover that if I'm to be competitive (rather than just a finisher) at the podium level for my age group.
Smilie will adjust my training regime accordingly.