The Apple Watch has a cool feature to measure your VO2 max, which is the maximum amount of oxygen your body can consume during exercise.

This feature is referred to as “Cardio Fitness” and it derives its measurements from estimations based on how hard your heart is pumping during an outdoor walk, run, or hike.

However, judging from a slew of complaints, this useful little function isn’t working properly for a bunch of users.


I was really looking forward to the new update and getting cardio fitness measurements from my new Apple Watch Series 6. However, even though I set everything up I get “no data” for cardio fitness in the Health app on my iPhone. By clicking on data sources & access I don’t see Apple Watch as a data source.

I got my Apple Watch for Christmas and have done a workout everyday since then, but cardio fitness still says ‘no data’ any idea of how long it takes for data to show up? Thanks

As clear from above, the entirety of the Cardio Fitness section shows up blank with sections like ‘data sources’ and ‘apps allowed to read data’ all showing no data whatsoever.

This shows that the Apple Watch isn’t detected at all because otherwise, it would show up under ‘data sources’. There’s clearly something foul at play since the Apple Watch should automatically show up under that section if it’s already paired with an iPhone.


Now, if you are a new user, then the first thing you need to ensure that the following parameters are met before the Cardio Fitness data can finally show up.

It can take at least 24 hours wearing your Apple Watch, followed by several workouts and passive measurements with your Apple Watch before you receive an initial estimate.

Even though Apple officially states a time period of 24 hours before the first instances of the data become visible, the actual time period may be lengthier – possibly a few days.

Additionally, as per many, you also need to walk/sprint for at least 20 minutes before the Cardio Fitness data registers and shows for that particular workout session.

That said, not everyone facing the issue hasn’t fulfilled the initial requirements. Many are old-time users that have regularly worked out for over 20 minutes for years but have recently started seeing ‘no data’ on their Cardio Fitness page.


In such a case, your best bet would be to try the following list of workarounds.

Workarounds for Apple Watch Cardio Fitness not working (showing no data)

1. Check if everything’s set up correctly: Firstly, you might want to visit this official Apple support article to make sure that there isn’t any slip as such.

2. Make sure that your workout is outdoor: Cardio Fitness was designed to work only with outdoor running/hiking as route tracking is crucial for it to function correctly. Plus, the feature uses GPS which doesn’t really function too well indoors.

3. Check Motion & Fitness privacy settings: If you are still experiencing the problem at this point, then it is highly likely that your iPhone/Watch doesn’t have the required permissions.

1. On your iPhone, go to Settings > Privacy > Motion & Fitness – turn on Fitness Tracking and Health.
2. On your iPhone, in the Watch app, go to My Watch > Privacy – turn on Fitness Tracking and Heart Rate.

4. Adjust data sources priorities: Try positioning your Apple Watch upwards in a manner such that it is above your iPhone, but below Health, within the data priority list. You can do the same as given below:


5. Turn off power saving mode: Power saving mode can theoretically interfere with proper fitness tracking and lead to sporadic data measurements. Therefore, you might want to turn it off from the Watch app. Simply head over to Settings > Workout > Power Saving Mode and toggle it off.

6: Calibrate your Apple Watch: For instructions on how to get this done, check this official support article.

7: Reset Apple Watch: If nothing else works, then your last resort could be factory resetting your Apple Watch from Settings > General > Reset > Erase All Content and Settings.

Hopefully, these workarounds helped. Be sure to let us know in the comments if that’s the case. Also be sure to check out our dedicated iOS 14 bugs/issues tracker.

PiunikaWeb started purely as an investigative tech journalism website with a main focus on ‘breaking’ or ‘exclusive’ news. In no time, our stories got picked up by the likes of Forbes, Fox News, Gizmodo, TechCrunch, Engadget, The Verge, MacRumors, and many others. Want to know more about us? Head here.

Zohaib Ahmed
824 Posts

Simply love being surrounded by technology as it's a constant reminder of how far humans have advanced as a race. Every new development feels exciting, which I convey to others through writing. And after a day's work, gaming just feels therapeutic.

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