I have a AET of 130ish and my HR drifts 5-6 bpm over an hour and I did a five hour run today and by the end of the run my HR is clocking 155ish but It feels easy, i can nose breathe pretty much, i feel tired but the HR doesn’t feel like it would if i just did a tempo run at 155-160 bpm for 30 minout of the gate.
is that normal, how do we adjust for HR rift over a really long workout? do i need to back off the effort to keep the HR down or is that drift alright over all, just trying to wrap my head around this, any help from an ultrarun perspective would be appreciated.