How to Measure VO2 Max Using Apple Watch

Did you know the Apple Watch can be used to give you your estimated VO2 max score? I didn’t, but you’ll be happy to know that it can measure it without you having to go through the more troublesome and traditional way of measuring VO2 max by running your ass off on a treadmill.

While not as accurate as the treadmill-oxygen-mask method the Apple Watch gives you a simple way you can start collecting and testing your own VO2 max.

What is VO2 max you may ask, here are FAQs about VO2 Max.

First off if you aren’t familiar VO2 max is (definition courtesy of Very Well Fit):

VO2 max, also known as maximal oxygen uptake, is the measurement of the maximum amount of oxygen a person can utilize during intense exercise. It is a common measurement used to establish the aerobic endurance of an athlete prior to or during the course of training

Basically it’s an indication of how efficient your body (muscles) is at using oxygen. The more oxygen you can use the better your performance. It is measured in milliliters of oxygen used per kilogram of bodyweight per minute (mL/kg/min). Besides tracking heart rate, resting rate, etc… you can use the Apple Watch to start tracking your VO2 max. Improving your VO2 max is challenging but very doable. If you are curious here is my VO2 max measurement taken from a 40 minute Outdoor Walk workout last month.

The only drawback to using the Apple Watch to measure VO2 max is that it is not as straightforward as getting other health data points to show up. Below is what you can follow to get it to show up in your Health App using your Apple Watch.

How to Get VO2 Max to Show Up

  • Start Workout on Apple Watch. Start a Workout using the native Apple Workout app (3rd party apps like the Nike Run club app or Strava won’t calculate V02 max for you)
  • Choose the Right Workout Type. You will have to choose from the following Workouts: Outdoor Run, Outdoor Walk, and Hiking (you’ll notice these are the workouts which use outdoor GPS… this means Indoor Run won’t work)
  • Workout for 20 Minutes or More. Do the above workouts for at least 20 minutes straight without pause
  • Check the Health App. After you end the Workout open the Health app and you should see VO2 max as a new data point

Notes on VO2 Max on Apple Watch

  • V02 is Estimated. Apple uses a predictive model (it’s an estimated Vo2 max) that was introduced during watch OS4. Specifically Apple says: “Values stored from Apple Watch represent a predicted VO2 Max, and are captured during intense Outdoor Walk or moderate to intense Outdoor Run sessions in the Workout app that are at least 20 minutes in length and maintain a persistent heart rate throughout the workout session.”
  • Use Apple Watch Heart Rate Monitor. 3rd party heart rate monitors might affect the reading (some people have reported not getting the measurement with their chest strap heart rate readers so only use the Apple Watch)
  • Not Always 20 Minutes Needed. While I’ve said to do at least 20 minutes of the above mentioned Workouts I’ve noticed that it is inconsistent. I’ve done short 10 minutes  walks and the measurement has shown up. This may be related to how strenuous a Workout is, but the best suggestion is to do the 20 minutes
  • How Accurate Is it? In case you were wondering how accurate Apple Watch and other fitness trackers at tracking VO2 max you can check out this article. Basically it says estimated V02 max measurements from fitness trackers could be under reporting your actual VO2 max

Products To Look Into For Tracking VO2 Max

So there you have it. Using just your Apple Watch you can now start tracking your VO2 max. In a year of tracking my own VO2 max not that much has changed for me but it’s kind of cool to periodically check on it and see if any changes have happened.

Give it a shot for yourself and let me know if that works for you or if you have other ways to get it to show up. I’ll keep this post updated with additional info as I discover it. By the way, it’s also possible to measure heart rate variability via the Apple Watch. Personally, I think the Oura Ring is the easiest and more accurate way to measure heart rate variability. 

If you are looking for other ways to measure, analyze, or optimiza your health, you can see check out this article on Apple Watch’s “hacks for health“. That articles talks more about different apps that are popular among Apple Watch users in regards to health.

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11 thoughts on “How to Measure VO2 Max Using Apple Watch”

  1. My watch s4 was showing progressive and fairly accurate improvements over a year lifting mine from a dire 25.9 to 39.8. I was very happy having put in a huge amount of work to improve my health! It was also properly measured at 40.2 in a full treadmill test. Not too bad for a 57 year old. Then with OS6 it fell off a cliff overnight and refuses to budge above 30.0 – it’s effectively useless as a measurement now.

    • That’s so interesting that the S4 with the previous Watch OS measured so closely with the treadmill test you took. While I find it nice to have the VO2 max measurement through the watch I still take it with a grain of salt. Like many measurements it’s probably good to see the trend and also how you actually feel during your workouts. If your times, reps lifted, distance traveled, etc… all increase you are probably maintaining and improving your V02 max.

    • According the Apple Developer site this is how you can get a VO2max reading:

      Apple Watch Series 3 and later estimates the user’s VO2max by measuring the user’s heart rate response to exercise. The system can generate VO2max samples after an outdoor walk, outdoor run, or hiking workout. During the outdoor activity, the user must cover relatively flat ground (a grade of less than 5% incline or decline) with adequate GPS, heart rate signal quality, and sufficient exertion. The user must maintain a heart rate approximately greater than or equal to 130% of their resting heart rate. The system can estimate VO2max ranges from 14-60 ml/kg/min

      If you follow what they say above you should be able to get a reading. Hope that helps!

  2. interestingly my VO2max as measured by my apple watch has gone from 44.7 to 29.7 in 2 weeks inspire of me working out more than usual. Is there an explanation for this

    • I wouldn’t take the Apple Watch VO2max measurements as gospel. Apple has a formula that estimates your VO2max and its their best guess and no way as accurate as doing a formal test (on a treadmill or bike in a lab). In your case, it doesn’t sound right that your VO2max would drop 15 points in 2 weeks. Have you noticed any changes since you posted your comment?

    • On Jan 29, 2021 my VO2 max dropped from 38.4 to 27.2. There was a watch OS update released on Jan 26. I figure something in the SW update impacted the calculation. My VO2 value has remained in the mid 20s since.

      • I actually had something similar happen to me as well. I got a new Apple Watch and initially my VO2 max shot up From 40 in November to 44.1 in December. My training didn’t change and the only thing was the new watch. From December onward each month it kept decreasing and bottomed in June at 35.6. Again, nothing changed in my training.

        All of this is to say, I’d take the Apple VO2 max stat with a grain of salt.


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