I have it set to %LTHR with default zones. I have done a lactate threshold guided test and it gave me 168 bpm, so the zones are as follows:
Z1: 65-80% (109-134 bpm)
Z2: 80-89% (134-150 bpm)
Z3: 89-95% (150-160 bpm)
Z4: 95-100% (160-168 bpm)
Z5: >100% (>168 bpm)
Now, after a single run, those settings change to %HRR with different zones. I have a max HR at 194 bpm and resting HR at 51 bpm:
Z1: 50-64% (123-143 bpm)
Z2: 64-72% (143-154 bpm)
Z3: 72-84% (154-171 bpm)
Z4: 84-85% (171-173 bpm)
Z5: 85-100% (173-194 bpm)
I would normally assume the watch is figuring out better zones for me, but they're so wildly different, and frankly, anything above Z2 is ridiculous in the new zones, that this must be some kind of bug.
How can I stop that from happening? Is it because of the auto-detect max HR function?
EDIT: also, it creates sport heart rates for sports I don't even practice, I only run.