So I bought the Forerunner 955 little over 1 week ago and I had put my max HR manually to 196 (highest I've seen when testing it out in the last year). In the course of this week Garmin auto adjusted that to 186 ... ok. So yesterday I did a tempo run and really pushed myself to register max HR on the watch so it would correct the max HR again. This is where I don't fully understand how this works with Garmin. I had a max HR of 198 during my tempo run, but the watch corrected my max HR setting to 192. I wonder why it didn't just push up max HR to at least the max value during the run. I ended up manually adjusting the max HR on my watch again. I hope this time it will not lower it again. Could it be because I'm doing mostly easy runs?