Issue with iOS 14 Fitness App and VO2 Max

So— I’m back. Here is my story: I contacted Apple and eventually got through to a senior advisor. She was extremely helpful. I sent screenshots of my data, pictures of a workout, and a chart showing declining VO2 max. We installed some analytics to my watch and phone, and then I did my regular workouts for the next couple of days. Afterwards I sent her a couple of screenshots and then was contacted by someone from “Health and Safety.” It appears that my watch did not record my heart rate at certain times so he had me change bands (I had at some point changed from my regular sport band to the metal one because it had gotten dirty). He said the sport band is made to be more accurate. I wore the sport band for the next several days and the VO2 max stayed the same and the heart rate chart was available each time. He says, “they’re not doctors” and can’t analyze the data but if you have a heart rate chart and VO2 max basically the watch is working. He had me tighten my band and move it away from the bone on my wrist (said it shouldn’t be touching it). I want to state that both people I spoke to were EXTREMELY helpful and answered all my questions. The bottom line- the new update is supposed to be more accurate than whatever they had before and Apple is always trying to improve, especially in the field of health and safety.

Did my V02 max improve once I changed bands and tightened the watch band? Not really. It went up .4 and seems to have stabilized there. Overall, I still went down 9 points, so I’m not a happy camper.

if anyone else finds out more, please let us all know. Going out to do my speed walk now. Maybe my VO2 max will improve. Ha!

So I upgraded from a series 2 to a series 6 watch and was unable to get a VO2 max reading for about a week. Tried repairing, factory resetting my iPhone nothing worked. Ended up going to the watch app Privacy-reset fitness calibration data and was able to get readings after completing the 20 minute calibration run but my results are about 5 points lower then my series 2 was giving me

I recommend going to the watch app, privacy, reset fitness calibration. You will have to do a 20 minute calibration run (flat ground outdoor run at a constant pace/heart rate zone) but after that you should get VO2 max readings close to where you were at before the update. At least that worked for me

They know there is a problem, as many of us have been in contact with Apple and submitted back their diagnostic tests.

My numbers dropped from mid 30's to low 20's after IOS14 and Watch OS 7.2 ..next day!

In work with Apple Watch support, I told them I had a similar beta blocker to yours noted, and they suggested I remove that info from the app. My numbers when up by 5, immediately, thus mid 20's, but still 10 below before earlier than the updates.

If you wouldn't mind, edit you beta blocker info off (Don't stop your beta blocker lol !) and see if your jumps 5 like mine !

We're all hoping the Apple Engineer update this bug soon !

Finally I think I got this to work! After several calls to apple and the promise that resting the calibration and this and that one service advisor told me to:

-goto the watch on my phone

-goto the fitness tab (green circle with runner)

-turn off power save mode

did a workout this morning and boom!

will continue to follow and see if it continues to function properly

hope this helps

Update about a 6 days (4 runs) after resetting the fitness calibration data through the watch app the initial 5 point (10%) drop on the first run seems to be correcting it’s self. On my last run I got readings within 0.4 points of what I was getting before.

Apple Engineers had me remove a VPN and an adblocker app, and want to see if my numbers go up,

I'm a bit dubious that's going to change anything, but according to the Apple Watch Support specialist

who is excellent in working with me, they know they have a problem, and I guess I have the inclination and the time

to work with them to solve this for a lot of people, Also being 75yo this is more concerning to me.

I have sent screenshots to her of Above Average V02Max stats with my prior AW5 which I gave to my wife,

then getting the AW 6 and immediately after 7.2 update dropped to Below Average or Low !

Another anomaly is that I have done an Outside Workout every day since the update, (approx 20 ) and when I go to the Fitness App on my iPhone and then Summary and scroll down thru Trends, is shows VO2 as locked straight line, and says I need

at least 5 readings to Unlock it, yet at the same time I'm getting these crap readings.

Big shout out to @msluparelli for reassuring me that my heart is working, but not the watch :)

Breaking news ! Actually received a call from a higher up at APPLE !!! Other than from the senior watch specialist who is diligently trying to sort out my 50% VO2 drop since 7.2 update. The knowledgeable Apple person who called, was noticing this/our thread and the growing number of us with the same problem. He had me do another diagnostic profile and called back for me to send the file. Also he may have chosen to call me to call as I'm 75yo, (and also take a Beta Blocker medication for slight higher heart rate) which I noted in the VO2 section. After he received the latest diagnostic file, he suggested that for the time being, to edit the Beta Blocker from the health app, which I did today, went for a brisk Outdoor Walk, and noticed that I went up from 19 to 26 ! But that is still below the the 33 - 36( or from Above Average to Poor for my age group) that I had been averaging before. Again, he noted that I might see an uptick, but the Apple Engineers are still researching the problem.

We also discussed that according to the Health Details, re:" Medications that Affect Heart Rate.......Apple Watch can take this into account when estimating your Cardio Fitness.!

I guess the good news is that we def have the attention of Apple on this, which reconfirms the article I mentioned above!!!!

I'm not sure where you have got your formulas from but they don't make too much sense to me. The way any device provides an estimate of your VO2max is dependent on more than just heart rate otherwise the most unfit people would have the highest VO2max as their heart rate would increase more for a given exercise. To get the best estimate of VO2max (noting that this is an estimate rather than measuring true maximal O2 uptake in a lab, wearing a mask & measuring O2 concentration & volume & work rate) you need the following variables:

A. Normal resting Heart Rate

B. Exercising Heart Rate at plateau

C. A measure of the exercise you are doing

The heart rate sensor in the AW will give you A&B. C is measured by your GPS giving distance covered, the pressure transducer which gives you change in altitude (i.e. if you're going uphill and hence harder work), and time to cover this distance and altitude. This gives the AW information on how far you are walking or running and how quickly, so it knows how hard you're working. This is why you won't get a VO2max on a treadmill/rower/indoor walk/any other instrument of physical torture because no watch, in isolation, can then decide whether you are working hard or not (though you can link other systems to it).

The algorithm then looks at your heart rate increase and compares this with how far & how high (altitude change) you have walked/run over a given time period i.e how hard you have exercised. You will get the highest VO2max if you can do a given level of exercise (distance and any increase in altitude)/time with the LOWEST increase in heart rate i.e. you are fitter. If you do a lot of intense exercise, over a period of weeks & months, your heart rate will increase less for a given level of exercise and your VO2max will increase.

Should all work OK, and give you trends more accurately than actual values. Unfortunately, the software updates have somehow messed up the algorithms or sensors such that there tend to be bigger changes caused by these than any exercise you do, which is annoying and should be addressed by Apple.

I hope that helps?

P.S. I'm an MD & PhD in this general area so I'm hopefully not wildly out.

It would require a workout between settings. Give it a day then check again.

Hello! I’ve seen improvements after Watch OS 7.3. My Vo2max is as it is supposed to be. Hope it helps.

In case this applies to anyone in this thread, accurate VO2Max readouts are known to be unreliable if your watch is synced to an external Bluetooth heart rate monitor during your activity (e.g Polar H10 chest strap).

I made a very detailed post about this in March of last year - https://discussions.apple.com/thread/251204981

Apple still has not resolved the issue.

Here's a suggestion for all VO2Max dropoff annoyed ! I must have mentioned this in my many obsessive posts here, but try this if you have access to someone who has an Apple Watch that has not been affected by this problem. Fortunately my wife has a series 5 AW that is not affected. I borrowed hers for a brisk Outdoor Walk, changed all her physical stats to match mine.

I wore a watch on each wrist for the same Walk. Then found the big difference in hers with my stats loaded on hers, if added to the stats on my AW 6, totalled to what I had been seeing before the update to IOS 14 and Watch OS 7 broke it.

So until the Apple Engineers fix the algorithms for us... know that you can relax a bit, and just add the difference.

Mine dropped dramatically from 42 which was steady for 3 months to 28 in one day and has stayed steady at 28 since.

I have found that on the day it dropped the setting for medication on my Heath information got turned on from 0 to 1. Telling the app you are on Beta Blockers etc will change the way the app reads you VO2. I have no idea how that happened but I have turned it to 0 again and I expect my VO2 reading to go back up again today after my exercise.

Unfortunately this is just a bandaid to the bigger algorithm problem that IOS 14 and watch 7.2 brought many of us, if you want to bore yourself looking at mine and other comments, recounting discussions with Apple Watch Support specialists, to this problem...to no avail !

Some of us are either older, or have heart related problems, thus have bought the watch for the much touted by Apple "Health and Wellness" features. Some have even gone to their cardiologists as they were worried about the precipitous drop after the update. So until Apple Engineers figure out what they did wrong with those updates, known that "It ain't you babe !"