This means Unproductive: Your training load is at a good level, but your fitness is decreasing. Your body may be struggling to recover, so you should pay attention to your overall health including stress, nutrition, and rest.
More info here: https://www8.garmin.com/manuals/webhelp/fenix5x/EN-US/GUID-6F81BF5B-B49A-4506-95E2-0F4A04D8B319.html
So it may mean you need more regeneration, you do not have to sell the watch. Try running less often and add some interval training to increase fitness. Or try some customized training plan.
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My training load has been at optimal level for the last 8 days
My vo2 max has now dropped to the low end of fair for my age.
Doesn't make scence as I'm breaking PBs in zwift sprints and recovering quicker.
Been at unproductive status since Jan 1st
Could it be the watch?
Any other advice?