Can Apple Watch tell you your VO2 Max accurately?

I thing you are misunderstanding what the VO2 Max measurement is meant to measure. The idea of the score is a measurement of how >efficiently< your cardio/respiratory system utilizes oxygen. This is measured by raising your heart rate, among other factors. At best, your watch can give you an estimate. An actual VO2 Max test involves running on a treadmill while breathing into a tube and having multiple sensors connected to your chest. Anything else is a rough estimate, at best. If Apple currently doesn’t measure a specific activity, it’s most likely because the accuracy is outside an acceptable standard. Not everything can be accurately (or even measured) from a limited number of sensors on a wrist.

I’ll share a video that helps explains the major factors.

https://youtu.be/A3YK_-8PrZw?si=QjiRDnnnbzPe-uo5

Have you read the information Apple has available to you in Health app on your iPhone? I’ll copy and paste it for your convenience.

>>This is a measurement of your VO2 max, which is the maximum amount of oxygen your body can consume during exercise. Also called cardiorespiratory fitness, this is a useful measurement for everyone from the very fit to those managing illness.

A higher VO max indicates a higher level of cardio fitness and endurance.

Measuring VO, max requires a physical test and special equipment. You can also get an estimated VO max with heart rate and motion data from a fitness tracker. Apple Watch can record an estimated VO, max when you do a brisk walk, hike, or run outdoors.

VO2 max is validated for users 20 and older.

Most people can improve their VO max with more intense and more frequent cardiovascular exercise. Certain conditions or medications that limit your heart rate may cause an overestimation of your VO, max. VO2 max is not validated for pregnant users. You can indicate you're taking certain medications or add a current pregnancy in Health Details.<<

You’re also allowed to add data, so that may be your best path forward if you don’t have confidence in your Watches measurements and calculations.

Brisk is, raising your heart rate approximately 20 BPM over your baseline. That will also likely trigger the activity being recorded as a Workout. Measurements may also be deleted, so again, adding and removing measurements that don’t meet your expectations may be your best path forward.