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WU27f1xcCs

macrumors member
Original poster
Sep 18, 2022
98
122
What happened my VO2 max suddenly plummeted, even though I am running like I used to. Is something wrong?
 

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BenGoren

macrumors 6502
Jun 10, 2021
499
1,421
First, yes, of course: you’re gonna die.

… but most likely not for quite some time, unless you happen to get hit by a bus.

Did you recently have a birthday, especially a “big number” birthday? I’ve seen similar stair-step patterns in my own VO2 max readings at such times.

Or, did you recently move to somewhere with a significantly different ambient temperature? Here in Tempe, Arizona (a suburb of Phoenix), I can see a clear seasonal pattern in my heart rate, both active and resting; when it’s hot, my heart beats faster. Both seem to be reflected in worse VO2 estimations. Understandable, I suppose … but it’s clearly the estimation that’s at fault.

I wouldn’t worry much about it.

Of course, if you actually do feel like you’re working harder all of a sudden, get thee to a doctor post-haste. But, if your only concern is this graph … just go for a run. At the mid-point, imagine that there’s a sign that looks exactly like this chart. Watch how rapidly it falls behind you, and enjoy the resulting freedom. And the rest of the run itself, of course.

b&
 
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WU27f1xcCs

macrumors member
Original poster
Sep 18, 2022
98
122
I haven’t had a big birthday or changed location. I wondered if they changed the algorithm, or if I have some sort of internal injury or fatigue that I’m not yet aware of, and I’m about to be hit with a massive injury…
 

GaryGnu

macrumors member
Nov 6, 2019
69
100
Where do you live? Maybe it has something to do with all the soot in the air from the Canadian fires?
 

leescottdavis

macrumors member
Jan 25, 2021
92
86
I haven’t had a big birthday or changed location. I wondered if they changed the algorithm, or if I have some sort of internal injury or fatigue that I’m not yet aware of, and I’m about to be hit with a massive injury…
Installed the WatchOS 10 beta?
 

WU27f1xcCs

macrumors member
Original poster
Sep 18, 2022
98
122
Just ran 14km and it has nudged up very slightly to 46.1, but still far below the 48 I’ve been at very consistently.
 

Bichon

macrumors 6502
Oct 17, 2019
274
459
Looking at my historical data, my VO2max plunged about 8 points (in one day!) between 9/17/20 and 9/18/20, and has never really bounced back. I always assumed this was a change in the algorithm, since there was no change in my fitness routine, nor any medical problem I was aware of.
 

Saturn007

macrumors 68000
Jul 18, 2010
1,559
1,447
A 2-point drop is not a plummet! 😁

You're still way up there, well above average.

In any case, the indicator is a crude one. An outing at a slower pace or with less exertion can change it. There's a plus-minus margin of error, anyway.

Besides, you know how ridiculous Apple's measure is when the categories jump from “Below Average” to “Above Average”! 🙈 ‼️

A tenth of a point difference changes someone from below to above average? Ridiculous! What happened to “Average”? The fixed dividing line or threshold is arbitrary. One doesn’t suddenly become above average due to a minor increase!
 

WU27f1xcCs

macrumors member
Original poster
Sep 18, 2022
98
122
A 2-point drop is not a plummet! 😁

You're still way up there, well above average.

In any case, the indicator is a crude one. An outing at a slower pace or with less exertion can change it. There's a plus-minus margin of error, anyway.

Besides, you know how ridiculous Apple's measure is when the categories jump from “Below Average” to “Above Average”! 🙈 ‼️

A tenth of a point difference changes someone from below to above average? Ridiculous! What happened to “Average”? The fixed dividing line or threshold is arbitrary. One doesn’t suddenly become above average due to a minor increase!
I had finally gotten to “high” though :(
 

macduke

macrumors G5
Jun 27, 2007
13,404
20,362
I haven’t had a big birthday or changed location. I wondered if they changed the algorithm, or if I have some sort of internal injury or fatigue that I’m not yet aware of, and I’m about to be hit with a massive injury…
If they were to change the algorithm, they would apply it retroactively for consistency. They know people rely on this data to see statistical changes in their values.
Nah nowhere like that
We live approximately 1000 miles away from the Canadian wildfires in the Central US, and my son has been having a terrible cough that has lowered his O2 somewhat. We took him to the doctor, and I kid you not, they blamed the wildfires and said they've been seeing a lot of that. He has no other symptoms, and has never shown signs of having asthma, but it's similar to asthma, which my daughter has mostly outgrown.
 
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