Hi. I apologize if this is not the correct forum to post this. I have a Fenix 5 (after a 735xt and a F620). I'm 47, and mi MaxHR is set to 185. G Connect and my Garmin watches detected a LTH of 164 BPM, sometimes 167 (when I feel better). Since I have the Fenix 5 I've logged into Training Peaks, Premiun because I still am in the promotional period. I went out today to do threshold work (2x20 minutes, 4 minutes rest between them) and the training peaks have detected a Lactate Threshold of 176. How reliable is this? Why can it be so different from Garmin?
Thanks