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A comment on I let ChatGPT analyze a decade of my Apple Watch data, then I called my doctor. Parent comment

Re:I let ChatGPT analyze a decade of my Apple Watch data, th... by smcl on Tuesday January 27, 2026 @03:48AM (#46777232)
Apple Watch is pretty poor at estimating VO2 max and it seems to be more correlated with how often you record exercises with said watch than with your actual health. For example I watched mine climb slowly as I prepared for my football season (beyond 50), then after the season started I I ended up playing and training just as frequently but without wearing the watch. After a few weeks (of me training and playing hard) during my next run it recorded me having a sharp decline in VO2 max (43-44ish iirc). When I started wearing it during training - you're not permitted during matches - it recorded me having a slow return to condition, without any changes to my routine.

That said if it's showing someone as having 30 I don't imagine they're going to be in spectacular condition

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Re:I let ChatGPT analyze a decade of my Apple Watch data, th... by eleveriven on Tuesday January 27, 2026 @05:49AM (#46778279)
This is really more of an "utdoor run while wearing the watch" proxy than a true fitness measure
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Re:I let ChatGPT analyze a decade of my Apple Watch data, th... by port11 on Tuesday January 27, 2026 @02:07PM (#46784725)
I really don’t know whether to trust that specific measurement. When I was a very active runner and doing intervals to improve per-km time, my VO2max went from 38 to 42. I decided to do a professional VO2max test and got a 46.

Now, 2 years later, I don’t run due to injury and a kid, and it’s resting at 34. For reference, when I went to the gym almost everyday and ran once or twice a week, the value was 32.

I don’t get much utility out of it, even looking at the trends. Not sure what Apple is doing behind the scenes to get the score.

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Re:I let ChatGPT analyze a decade of my Apple Watch data, th... by smcl on Tuesday January 27, 2026 @06:27PM (#46788665)
Yeah so I know it's meant to be an estimate, but my experience of it is kinda fucky. I would really love to swap watches with an Olympic athlete (idk if they'd bother with an Apple Watch but bear with me!) and run 10k to see what the VO2 max reading for that exercise was. As I said, I think to me it's some estimate that heavily involves some "average of last N readings from the Apple VO2 max calc" function so even if you time travelled and gave it to Eilish McColgan or Mo Farah they'd be like "ehhh you had quite a good run, fatty - you jumped from 44.3 to 45"

I'm not that bothered of course. For me it's just a fun metric I can attempt to optimise when training.

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Re:I let ChatGPT analyze a decade of my Apple Watch data, th... by port11 on Thursday January 29, 2026 @05:30AM (#46808208)
That experiment might be unfruitful because I assume Apple’s algorithm was not trained on outliers. Very capable athletes might see similarly silly data because they don’t fit well into the bell curve. Maybe.
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