I have an Apple Watch Series 2 running WatchOS 4.0, and an iPhone 7 running iOS 11.0.1.

One of the new features of the new OS on the Apple Watch is the ability to calculate a VO2 Max for any run longer than 20 minutes.

I have been on 3 such runs since the update, and 0 of those times has the Health App on iOS given me a V02 reading.

Under the "Data Sources" tab for V02, nothing shows up as a possible source, not even my Apple Watch 2.

I have attempted to switch on and off the Privacy Settings in the Watch App on iOS for Heart Rate and Fitness Tracking to get the watch to connect for V02. Both have been on, during my runs. This did not resolve the issue.

How can I force my Apple Watch to act as that data source for V02 Max?

  • for what it is worth: I have an apple watch 2 and I'm getting VO2 max from walks and other workouts (no runs, I don't run). It may be that it takes a little while to start calculating the VO2max... have you gone back to see if it is recording now?
    – dwightk
    Commented Mar 20, 2018 at 15:47

2 Answers 2


I went for a 2:30:00 run yesterday with my iPhone (6s) in my bag and my watch running strava. VO2max was recorded once per hour in three hours (10-11/11-12/12-13). I’ve tried to get VO2max off of shorter runs (5k-10k) on the same route without my phone but no data. I will now have to test longer runs with just watch and shorter ones with phone to get a definitive answer. Hope this is helpful. enter image description here

  • Doesn’t this answer say the calculation only happens once per hour? Seems like a good contribution to me, @Jawa
    – bmike
    Commented Oct 11, 2017 at 10:37
  • I interpreted it as a comment, based on empirical observation. How is it related to "How can I force my Apple Watch to act as that data source for V02 Max?"
    – Jawa
    Commented Oct 11, 2017 at 10:43

It’s a bit naive, but have you read the instrucctions under VO2? enter image description here

  • what is the source of this text?
    – pkamb
    Commented Dec 9, 2019 at 22:51
  • 1
    You can read it in the description section of VO2 ("About VO2 max"), at the bottom. Commented Dec 10, 2019 at 10:55
  • At the bottom of what?
    – pkamb
    Commented Dec 10, 2019 at 16:35
  • 1
    Go to HealthApp->Browse->VO2max, then scroll the bottom. Commented Dec 10, 2019 at 16:46

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