VO2 max dropping

sals25

Hi all, in the last two years I’ve dropped 5.5 stone, when I started loosing weight I started walking for exercise, my VO2 max started out at 20.6, fast forward to this year and I’m able to walk five miles in just over an hour and my vo2 max in March was 33.9, I came down with a bug (I’m convinced it was Covid but tests were clear) and it quickly dropped back to 31.9. Since then I’ve continued walking, maintained my weightloss, I had started trying running but hurt my leg so have had to just keep on walking. My VO2 max had started to increase again but in the last two weeks is reducing, with no real reason for it. So my question is this, is the decrease an indicator that there is something wrong with me health wise? Or am I’m overthinking it and using it as the wrong metric to gauge how well I’m doing?
Thanks in advance for any advice. For context I’m 46 and roughly 150lbs

SoCalSwimmerDude

OP, given that you’re not overweight and you exercise regularly, my input will be a little more straight-forward than others….

You’re all good. Congrats on being healthy.

Lietchi

Is this your VO2max according to a fitness tracker? Those aren't as reliable as proper VO2max tests in a lab setting.
I'm also not convinced estimations of VO2max based on walking are reliable - usually it's based on running or cycling.

I don't believe the number my Garmin gives me, I rather look at my resting heart rate, HRV and how high my heart rate is during my 5k runs (keeping my heart rate lower for the same speed).
Generally speaking, looking at the trend rather than the absolute number should be OK.
But I'm not sure if your decreasing number is due to changes in your heart rate, or perhaps just an update of the algorithm used by your watch (I've had that happen in the past)? So that's why it's good to look at your other stats.

Also: you mention maintaining your weight, so I guess it's not relevant here, but increases and decreases in weight influence your VO2max too. If you have for example a VO2max of 36.6, rounded up to 37, and you then gain a few lbs, your VO2max could become for example 36.4, rounded down to 36.

yirara

Everything that Lietchi said. I had two actual lab tests that gave me results for VO2max that were about 10 points lower than what my garmin claims. For running, uploading my data to Runalyze I get fairly good estimates similar to the lab tests. VO2max for walking? I don't know what kind of device has this functionality, but I'd take it which a huuge block of salt.

sals25

Thank you both for your responses. The info is taken from my Apple Watch. To be honest I’m just happy not to be overweight any more and I think I was using these stats as an indication that my overall fitness has improved.

ninerbuff

Eh, wrist worn trackers aren't really that accurate so don't fret. Fitness could likely be better hence a lower reading.
Remember these are tools to assist you to help lose weight. But they aren't the real indicators since how you feel and your clothes fitting looser aren't checked by those.

A.C.E. Certified Personal and Group Fitness Trainer
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AnnPT77

Leaving aside the actual numbers from your tracker (which I agree are approximate/estimates), I don't think the trend you're seeing would be super unusual. Please note, though, I'm not a medical professional!

You had a disease with respiratory component. I'd expect that to potentially reduce VO2max temporarily. If the illness reduced activity level or intensity, the reduced activity level could also reduce VO2max.

Your VO2max started coming back up with recovery and increased activity, which makes sense.

You say that you had to stop running because of a leg injury, and drop back to walking. How did the timing of that correlate (or not) with the most recent decline in the VO2max estimate? Higher intensity exercise (like running) is known to increase VO2max more effectively than lower intensity exercise. It wouldn't be surprising if reduced intensity might reduce VO2max, perhaps particularly in a scenario where it had only recently begun to increase.

I get estimates from my Garmin based on walking (although walking isn't a significant part of exercise for me). Those estimates meander up and down randomly by a point or two for no apparent reason. That's without any kind of dramatic change in anything at all in my health or routine.

If you're talking about changes within a small number of points of estimation, personally I wouldn't worry about it, as long as there were no cardiac or pulmonary symptoms (light-headedness, wheezing, unusual heavy breathing during accustomed exercise, faintness, chest pain, etc.).

But again, not a medical professional: Just a 68F whose been active for around 20 years, looking at these VO2max estimates in myself for around 6 years so far.

rimcdave

There are some physical tests that you can do yourself that will give you a pretty accurate measurement of your VO2Max.

The Rockport test for walking.

The Bruce Protocol test for treadmill.

The Cooper test for running.

The Bruce Protocol is used by major Hospitals in the US to access VO2Max and aerobic condition.
The Cooper test is used by the majority of the Military and Law enforcement agencies to access VO2Max and aerobic fitness.