Originally Posted by Iride01

Unproductive I've taken to mean that I'm not doing anything to maintain or get better. High aerobic shortage is it trying to tell you you aren't getting enough of higher aerobic HR zones in your riding.

If you just want to ride your bike, it's no big deal. Just ride your bike as you see fit, ignore Garmin.

For me the messages seem to go pretty much hand in hand with what I'd expect. Sometimes I disagree, but which of us is right I don't know since there aren't enough copies of me to go out and try different strategies.

If you are trying to improve something about your cycling, then use it's suggestions along with all the other stuff you know as tools to indicate what you might need to do.

Do you have your HR zones set up? While you say you are doing some hard rides. Too much of it might be very hard effort and anaerobic and not just high aerobic. Might be bouncing from anaerobic effort to low aerobic for your resting and missing the high aerobic entirely.