I’ve found that the only thing that improves my VO2 max is long slow jogs in cardio Zone 3. Anything else actually drops it.

VO2 Max for Apple Watch is useless for anything but pure runners.

i’m doing cardio regularly like boxing and hiit but vo2max didn’t increase at all, stay “below average “ forever

The Apple Watch will generate a VO2 Max estimate value after doing an outdoor running, walking or hiking workout or activity on relatively flat ground, with good heart rate and GPS data, and that equals or exceed a certain intensity.