Thanks for the response @michaeltyoung
There’s some great info there.
I was trying to test straight after my run thinking that it would be a good check to ensure I was in Z2 before I make the time to do the proper treadmill test (need access to a treadmill). But if the results are likely to be that sensitive to a slight delay, maybe thats not going to be a useful practice.
I’m looking forward to finding a treadmill and partner to help do the proper test protocol. My current AeT is based on the TrainingPeaks HRV method and was done a while ago (my TP expired and I wasn’t feeling the value of renewing).