Vo2 max dropped suddenly with new series 9 watch

Hi everyone. I owned a Series 4 watch for about three years. My VO2 Max reading fluctuated in the range of above 30 to 33 but recently around 32. I am a healthy 64 year old who exercises virtually every day. I replaced the 4 with a new series 9 about a month ago and used the series 4 backup data to set up the watch. Again the VO2 max reading of the new watch was very similar. I had to return the series 9 after two weeks as the microphone was faulty and Apple gave me a new identical watch. Again I restored from the series 9 backup. Straight away from the first workout my VO2 max plummeted overnight to around 22.5 and has been stuck there for the last 7 to 10 days (over 4 workouts or so). I read the other posts about "calibrating the watch" which didn't seem to be anything other than doing a workout in the open for about 20 mins (which is what I was doing). I also followed the suggestion to reset the calibration data. I did this twice. None of this changed anything. I am running the latest Watch OS and iPhone iOs (iPhone 12 pro).My fitness levels have gone overnight from "above average" to "below average" which is quite discouraging.


The heart rate readings seem to be ok with similar levels during workouts and when resting to the old watches.


Any help appreciated. I really don't want to return the watch again for such a silly issue but I am out of things to try.


Thanks

Apple Watch Series 9, watchOS 10

Posted on Oct 18, 2023 1:41 AM

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Oct 19, 2023 6:13 AM in response to jeffreyfromperth

Greetings jeffreyfromperth,


It sounds like you have questions about your Apple Watch and your cardio fitness levels. We know how important this is for you, and we will help get you to the right place for answers.

How Apple Watch estimates your cardio fitness levels

Apple Watch Series 3 or later can record an estimate of your VO2 max using the heart and motion sensors during an Outdoor Walk, Outdoor Run, or Hiking workout in the Workout app. Apple Watch supports a VO2max range of 14-65 mL/kg/min that is validated for users 20 years or older.

To estimate your cardio fitness level, your Apple Watch also takes into account your:
• Age
• Sex
• Weight
• Height
• Medications that might affect your heart rate

It can take at least 24 hours of wearing your Apple Watch, followed by several Outdoor Walk, Outdoor Run, or Hiking workouts* and passive measurements with your Apple Watch before you receive an initial estimate.

If the Health app detects that your previous cardio fitness estimates could be more accurate, you'll have the option to update your data. In Cardio Fitness, tap Update under Update Your Data. After you update, the Cardio Fitness Data Updated notification shows you the results of the update and how your estimates changed.

This info is located in this support article: Track your cardio fitness levels - Apple Support


If you need continued assistance, please get in touch with the Apple support team via this link: Get Support.


All the best.


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Vo2 max dropped suddenly with new series 9 watch

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