I've always struggled to set my HR zones properly so I set my FR255 to auto-detect Max and resting HR and set my HR training zones based on %HRR which I think is based on the Karvonen formula. Today, I went for race pace 5k run and my Max HR hit 188, which is higher than my previous recorded max of 185. After my run, my watch automatically notified me it adjusted my Max HR DOWN to 182. So I'm bit confused. Is it trying to average my redline zone over period of time, while I was in Z5?
Just curious how this works. Also I ran the 5k just to see how it matches up to the "Race Predictor" feature. I was still off the predicted 5k race pace by 2mins slower - instead of 6:40min/mile pace, I was running 7:16. Again, I redlined and hit Max HR, but my initial pacing was a bit off and I did have some uphill and downhill. Factoring those in, I think I could have run 20-30s faster in ideal and flat conditions. I'm not super concerned, it's inaccurate, but AFTER my 5km run, the race predictor didn't change/adjust for my slower time. It's actually predicting a few seconds faster - based on my VO2max improving. My VO2max number stayed steady - but the training effort says improving, so maybe there are incremental changes it tracks.
Anyway trying to understand how these features work and if they will become more accurate over time, or if I should just ignore them!