I recently ran a local 5k in 24:21 (pedestrian by ST standards I know, but coming back from 2 yrs off of running and wanted to get a baseline). I did a 1.5 mile w/u before the race and my question is how can I use my avg HR for the 5k to determine my LTHR?
I would expect it to be 5-10bpm higher that LTHR if you raced it correctly (ready to puke crossing the line). 5k is closer to VO2max than LTHR.
You might however use it to predict you threshold pace. Then on you next run, hold that pace for 1 mile and see what you HR is at that point.
I find HR in races to always run a little high due to excitement and don’t like to use them for training. I use paces from races and work backwards into training HR zones.