Apple Watch Cardio Health exhibiting no knowledge? This is what you are able to do


The Apple Watch has a cool feature of measuring your VO2 max, which is the maximum amount of oxygen your body can use while exercising.

Called cardio fitness, this feature derives its measurements from estimates based on how hard your heart is pumping during a walk, run, or hike outdoors.

However, judging from a number of complaints, this useful little feature is not working properly for a number of users.


I was really looking forward to the new update and to getting cardio fitness readings from my new Apple Watch Series 6. Although I have set everything up, I do not receive “no data” for cardio fitness in the Health app on my iPhone. When I click Data Sources and Access, I don’t see Apple Watch as a data source.

I got my Apple Watch for Christmas and have worked out every day since, but Cardio Fitness still says “no data”. How long does it take for data to appear? Many Thanks

As shown above, the entire Cardio Fitness section appears blank. Sections like “Data Sources” and “Apps That Are Allowed to Read Data” do not contain any data.

This shows that the Apple Watch is not recognized at all, otherwise it will be shown under “Data Sources”. There is clearly something bad at play here as the Apple Watch should automatically show up in this area if it is already paired with an iPhone.

Cardio fitness-no data


If you are a new user, you must first make sure that the following parameters are met before the Cardio Fitness data can finally be viewed.

Your Apple Watch can be worn for at least 24 hours, followed by several training sessions and passive measurements with your Apple Watch before you get an initial estimate.

Although Apple officially gives a period of 24 hours before the first instances of the data become visible, the actual period can be longer – possibly a few days.

In addition, as with many, you must run / sprint for at least 20 minutes before the cardio fitness data for that particular workout is registered and displayed.

However, not all who face the problem are those who did not meet the original requirements. Many are old users who have exercised over 20 minutes regularly for years but have recently stopped seeing data on their Cardio Fitness page.

Apple Watch Cardio Fitness

In such a case, it is best to try the following list of workarounds.

Workarounds for Apple Watch Cardio Fitness not working (without data)

1. Check that everything is set up correctly: First of all, you may want to visit this official Apple Support article to make sure there is no receipt as such.

2. Make sure your exercise is outdoors: Cardio Fitness was designed for outdoor running / hiking only, as route tracking is vital to its proper function. Also, the feature uses GPS, which doesn’t work really well indoors.

3. Check the Motion & Fitness privacy settings: If the problem still occurs at this point, it is very likely that your iPhone / watch does not have the required permissions.

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

4. Adjust the priorities of the data sources: Position your Apple Watch up so that it is above your iPhone in the data priority list but under Health. You can do the same thing as given below:

Apple Priorize Data Sources


5. Switch off the energy-saving mode: The low power mode can theoretically interfere with proper fitness tracking and result in sporadic data measurements. Hence, you may want to turn it off through the Watch app. Just go to Settings> Exercise> Power Save Mode and turn it off.

6: calibrate your Apple Watch: Instructions on how to do this can be found in this official support article.

7: Reset Apple Watch: If nothing else works, you can factory reset your Apple Watch via Settings> General> Reset> Erase All Content and Settings.

Hopefully these workarounds helped. Let us know in the comments if so. Also check out our dedicated iOS 14 Bugs / Issues Tracker.

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