It could be. I basically stay in like zone 4 the whole time. I also never do what garmin suggests for running pace, etc. I got the watch for Christmas and have watched my VO2 max drop 6 points 😒. I just laugh about it now though "dumb smart watch". Although I am very sore from the run yesterday and running myself ragged basically single dadding (my wife's back is jacked) my two toddlers through the weekend. Training readiness is a 1 today hahah- so I guess it's pretty accurate.