Sudden drop in VO2Max recorded on Apple Watch

I'm not sure it's the phone per se. I got my new iPhone 12 mini months before the sudden overnight drop in VO2 max. It would be really nice if someone knowledgeable at Apple would chime in here and let us all know what happened and how to fix it (for real--not the same old same old that doesn't work).

I have experienced this issue since Dec 2020/Jan 2021. I have a Series 3 watch , owned since July 2019, and the new iPhone SE which I’ve had since September 2020. I’m a 21 yr old female who walks at least 3 miles everyday and does at least an hour of HIIT/cardio/etc as well as a uni student. In Dec 2020 I recorded an average of 38.8 VO2. Suddenly in Jan 2021 it dropped to 35.4. Didn’t think much of it as I had changed my routine slightly to cope with uni work. It then dropped again and now sits at around 30.1 VO2 despite an increase in walking distance, occasional run and my routine picking up again. This is very disappointing to someone like me who has struggled a lot with their view toward their body image and workout routine, often having to reminded not to overtrain and such.

I went from 37.8 to 33.8 over the last month and I just finished a workout where I was ripping it and was certain I was in better shape than when at 37.8..

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(and no, I have not picked up a 4 pack a day Marlboro habit in a month).

i used an iPhone eight max. just switched to a 12 mini. My VO2 was running about 22 for three months but in February it dropped to 15 or sometimes below. (An approximation for VO2Max is your max divided by your average times 15. A score less than 15 mins my max must be less than my average so this sounds quite wrong.). Apple does not give its formula. I am 80 years old and I suspected they made a different Adjustment for age, which would explain a sudden drop that is persistent. But I am assuming all the rest of you who are doing this are younger. So anyway it would be a problem occurred with an 8 max and persists with a 12 mini.

2019 through April 2021 I averaged above 40. The last three month was 43. Then in April and ever since I dropped to 27. I have no health risk factors. I have changed no exercise routines. This is very frustrating because what data is to be believed?

Hey Guys

I have experienced the same glitch on my Apple Watch

I peaked at 38.7 back in May for my fitness level, every since then my number has dropped to now 35.5.

i jog 5 miles 3X to 4x days a week.

Something weird is happening with these Apple watches.

I experienced a drop in May, my birthday is in March.

on the Apple website I see that they released a patch for WatchOS May 3rd, and I probably installed it days later.

My vo2 drop happened between May 6th (46,7) and May 11th (36,3). I believe I did the watchOS update between those dates.

I did daily runs for the next seven days and it was up to 42.9 on May 17th.

May 28th it was up to 45,8 and August 9th it’s at 47,3.

I’m a nervous wreck whenever there’s a new patch, but the recent patches went well. Haven’t experienced a drop again.

Great reply. Unfortunately no birthday.

My VO2 Max is now pretty consistent at “above average” 34.5. I’m 70 next year so I’m trying to improve as best I can. Less food, less alcohol and more exercise. Hopefully some fun as well 😂🏴󠁧󠁢󠁷󠁬󠁳󠁿

I did not. Ironically it dropped again last week, not quite off the cliff, but still not right. I have a friend at Apple that I sent to and he's trying to get some answers as well. It's so bizarre. My fitness is much better right now than anywhere close to what it was 6 months ago and the charts showed that improvement until overnight it's as if Apple thinks a lung was ripped out of my body and no longer have V02 capability. Frustrating.

I went back and checked. Found that I had been switched from a 1956 birthday to an '84. No idea how it happened. Some other info in my profile was also screwy. Adjusted it and went back to normal/previous reads. Dropped from 44-45 V02 to barely 30, now back up to 48-49.

I checked my DOB in my health app and it was correct. I am still trying to figure out why my VO2 max went down so much, so quickly, and my wife's watch did the same thing.

I might think that the drop was because we both had COVID, but that was nov 2020 and the drop was this May....

VO2max is climbing again, it broke the 30 barrier, which should be past 40 based on previous readings(?)

Vo2Max is only measured in an outdoor walk or run or hiking workout.

The instructions at "Set Up Cardio Fitness" do not work. When I followed them, I could not find a "setup" option. I have an iPhone 12 mini running 14.4.1. Can anyone find better instructions?