VO2 Max going down but Fitness points are increasing

Daveais

I'm a 6 day a week active person
A week and a half ago my VO2 Max was 53 - I completed a HM race and got 1600 points for it (I am also a little bit sick).
3 days later I did a 10k tempo run - VO2 Max goes down to 50 and my Fitness points are 1576????
Did Intervals next day - VO2 Max didn't move (that's okay)
Did parkrun (5km run) on Saturday - Heart rate drops half way through from 160 to 110 - fitness points drop to 207. V02 Max increases by 1
Did a slow HM on Sunday and VO2 Max drops by 3. Highest ever fitness points 1700+
Yesterday did a 10k run and again over 1500+ Fitness points and VO2 Max drops by 1.
So VO2 Max has dropped by 6 in a week and a half.
Am I sick or dehydrated? is my watch playing up?
(All runs post initial HM have been on flat grade)

tfarabaugh

Unless you are in superb shape the initial VO2Max was likely wrong nd it is slowly correcting itself. I honestly don't feel you can make any judgments from what it is telling you in terms of fitness points or fitness age. It only uses runs or cycles to calculate points and while it does refine its readings over time, but it seems to be a random, capricious measure that ties to very little. It uses your calculated VO2Max (which will be wrong as no watch can compute this) to calculate points. It is not the amount of exercise that matters, it is the intensity. Unless you are in Z3 or higher for a substantial part of your workout it will not change anything. If your workouts are walks or jogs or anything that is not intense, it will have no impact on the age and points. It is based on whatever algorithm TT came up with, which is different than what Garmin uses or Strava uses, or anyone else. Ultimately, I don't expect a watch to be able to tell me how fit I am.