I did the 20-minute test at the start of my plan to determine LTHR and LT Pace. About six weeks in now I did a 5k time trial last night as a sort of check-in. I went 35 seconds faster than I expected, which was great. I plan on using this time trial result to adjust my pace zones. Which brings me to my question, these pace zones seem likely to nudge me out of my heart rate zones. Conveniently, the 5k lasted just a couple minutes over 20. Could I use it like a 20-minute test? Is there any value in treating the 5k like a 20-minute test and using it to re-evaluate my heart rate zones as well?
I ask because this would bump my LTHR up 8 – 10 bpm and while I’m not 100% sure as today’s a rest day so I haven’t gone out and done a Foundation run. It feels more likely LTHR and LT pace will be aligned if I use the latest time trial to adjust them both.