max heart rate - auto detect is turned OFF but keeps reverting

I started the Garmin run Coach (not daily suggested workouts and not celebrity coach) on October 1 and the threshold and tempo workouts have a heart rate range that is way too high for what I can achieve. It had extrapolated a max heart rate of 181, but I am 57 years old and I am not fast. 181 is too high. My age-predicted max is 163 so I turned auto-detect OFF and manually selected 170 for my heart rate max. GARMIN KEEPS CHANGING IT BACK! The Garmin run coach changed the heart rate range goals in the app temporarily. By the time I selected the workout from my watch, It was telling me to run 10 minutes with a heart rate near 165. I can't run that hard. Subsequent threshold and tempo workouts have resulted in lower than average "execution" scores, because I can't run that hard for that long.
I am not new to running or Garmin. I know I can just do my own training plan, but this is vexing!

0 Etupes25 3 days ago

There is not much you can do except using a chest strap when running. If you use the wrist HR, you are bound to have less accurate data, despite all the good technology on the watch to suss out reliable data.

If you are using a chest strap, there is a good chance that the auto-detected max HR is more correct than your age predicted max HR.

The watch will take some time to learn/rebuild the model that links your ventilation (VO) to your output (pace). That model is the foundation behind many training metrics.

You could consider doing a watch backup, a factory reset, and NOT reconnect the watch to the phone or your wifi. The watch will reset its models. You would go run a variety of run workouts with a chest strap using the suggestions for a couple of weeks and see if the estimates get better. If nothing improves after a couple of weeks, you can restore your backup and reconnect your watch.

About the watch changing the Max HR if auto-detection is off. Maybe there is a bug in the watch firmware. Maybe there is an issue with synchronizing your account and/or across devices. Doing the reset couple of weeks test could determine that.

If the HR zones and target end up being better, I would still suggest you use a pace target for your workouts. When you train, you should aim for steady pace for whatever interval you go for. Using HR targets makes it harder because of HR lag.

0 deannarunsround 22 hours ago in reply to Etupes25

I repeat; am not new to running or Garmin. I use a Polar optical sensor on my upper arm. I use the Garmin HRM-Pro for cycling. I know the wrist-based optical sensor on the watch is shite. I have owned this watch since it was released. I am not relying on age-predicted heart rate max, I know it's higher than 163, but it is not 181. The issue remains that the watch and the app are not staying in sync. My half-marathon is in 11 days and I have neither the time nor the inclination to experiment with a "variety of run workouts" or watch resets, and I shouldn't have to. It should work as designed.

0 Etupes25 19 hours ago in reply to deannarunsround

deannarunsround said:
I have neither the time nor the inclination to experiment with a "variety of run workouts" or watch resets

Then, you should contact Garmin Support. Maybe there is an issue with your account synch.

deannarunsround said:
It should work as designed.