My Apple Watch is 20% wrong about my VO2max!
I (36F) just learned that my Apple Watch was significantly underestimating my VO2max.
For the past several months, I’ve been training specifically to improve it. I do one Norwegian 4x4 session each week and follow structured 12-week training blocks with planned load and deload weeks. Since I live in Austin, TX, where it’s brutally hot most of the year, I mostly train on a treadmill and only run outside every couple of weeks so my Apple Watch can generate a VO2max estimate.
The results were frustrating. One outdoor run would bump my VO2max from 33.2 to 33.3, then the next would drop it back to 33.0. It barely moved despite noticeable improvements in my treadmill performance.
So I decided to get a CPET (cardiopulmonary exercise test), where they measure your oxygen consumption directly while you exercise.
The technician expected me to last at least 12 minutes, but I made it past 14 minutes and still felt like I had more left.
My measured VO2max came back at 40, with an aerobic threshold of 150 bpm. According to the lab, that puts me in the “excellent” range for my age.
It made me realize how much Apple Watch estimates can vary, especially if most of your training is indoors. If I had relied only on the watch, I would have assumed months of structured training
had barely made a difference.
Has anyone else compared their Apple Watch VO2max with a CPET? How close or how far apart were your results?