Garmin training zone change

Hi all,

Do Garmin training watches such as the Fenix 5 automatically change training zones (HR).
One of my client’s watches changed the zones down?
At this point we don’t know why.

Thank you

Check the max HR on the watch. I had my zones all automatically go up on my 935 when it erroneously detected a new max HR due to an HR strap glitch (single spike sent my max HR from 185 to 250). Since I don’t train by the zones on the watch I didn’t notice for a while until my predicted vo2max went through the roof over a couple of months.

Don’t know why it would go down though, not sure if it uses resting HR in settings the zones or not, but that might be something else to check.