How Health.app Prioritizes Data From Multiple Sources

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Have you ever wondered how iOS and more specifically the Health app handles and prioritizes data from multiple sources?

I have an Apple Watch and an iPhone and both devices, if worn or carried at the same time, record the number of steps I take, among other data. Yet, the Health app reports the number of steps accurately and prevents duplicate data entry.

Until recently, I didn’t think about this because I naturally expected Apple to have figured out how to prevent duplicate data reported by both the iPhone and the Apple Watch.

Apple and Third-Party Devices

However, yesterday I got a Jawbone UP2 and the thought crossed my mind when the UP app asked for permission to read and write health data such as number of steps taken.

I’ll explain the reason behind buying a Jawbone UP2 in one of my next posts.

I talked to Apple to find out more about how Health prioritizes data from multiple sources and I was pointed to the following knowledge base article.

Turns out you can set the priority of your data sources for each attribute of your health data.

Default Priority

By default, Health uses the following order to prioritize sources:

  1. Health data that you input manually.
  2. Data from your iPhone, iPod touch, and Apple Watch.
  3. Data from other third-party apps and Bluetooth devices.

Between the iPhone and the Apple Watch the following order is set by default:

  1. Apple Watch
  2. iPhone

That confirms what I expected, iOS and Health are smart enough to prevent duplicate data from being reported and it’s nice to know that I could change the priority manually, if I was so inclined.

Stay fit!

14 thoughts on “How Health.app Prioritizes Data From Multiple Sources”

  1. Anybody ever happen to figure this out? I had to unpair and repair my series 3 watch a few weeks ago for a bug syncing contact names in messages to the watch. Now I have 2 of the same watch listed in sources and am getting a series 4 watch so I’ll have 2 entries for the series 3 watch. Just an annoyance and it’s hard to find like minded people who suffer my affliction lol. Really want to combine this data for the same source as it should be. I don’t mind the series 4 watch being separate as it’s, well a different source!

    PS here’s another annoyance for you to check and see if you’re affected… Under sources my phone is listed with the proper name assigned in General/About. However, if I look at a metric like steps which the phone writes data to the health app for, then look at sources, the phone name is actually the name of my phone two phones ago. This same source has carried over and all data is listed from then until current. So in main sources it’s named properly and in the actual data/sources it’s incorrect. Really annoys me LOL

    Reply
    • My OCD solution to this issue is not to look at the source list :)
      If you have ever used the Apple Wallet (used to be called Passbook) on iOS, you’d notice that iOS never gets rid of any old boarding passes. I must have hundreds of passes in there that I cannot get rid of.

      Reply
  2. Hi Michael

    I’m having an issue where my wife’s iPhone is showing up in my Health app? Is there a way to delete this (without deleting the data from her phone)?

    I’m afraid the problem is caused by sharing the same AppleID on both phones? they have been set up before family sharing was possible… :o(

    Reply
    • In my opinion, the best course of action is to create another Apple ID and stop sharing one. I don’t know if removing her iPhone from your Health app will remove the data on her phone as well. I’d contact Apple support via Twitter and ask what they’d recommend.

      Reply
    • Hi Lak!

      In the Health app on iOS, go to Health Data (bottom of the screen) and then select a health metric, for example, Steps or Heart Rate. Then click on Data Sources & Access and Edit (upper right). On that screen, you can change the priority.

      Reply
  3. Still can’t win this war. Both my wife and I have the Apple Watch as priority on top. Always, the apple watch as more than the phone. My wife leaves phone on tables a lot and the health app some days has half.

    Reply
  4. Hi Michael, could you please advise which device/app should one prioritize for best accuracy? For example, I noticed that by default my AW3 was set on top of the list of prioritized sources in some cases (I believe Steps and some other sections in Health app), yet in some cases it was my iPhone. In a few other instances the NRC app was on top. Usually I use my AW3 in combination with my iPhone (in my pocket), so my question would be which device to prioritize? Should I put AW3 first in all sections or iPhone? Wouldn’t iPhone have more sensors than the AW? Thanks

    Reply
    • I have my Apple Watch as #1 and iPhone as #2. Whatever you wear more frequently should be #1. The iPhone doesn’t have more or better sensors when it comes to tracking health-related data.

      Reply
  5. Thank you so much. I was having trouble with my Apple Watch steps showing up properly in my Weight Watchers app. I followed your directions to change the priority of my data sources, and now all is well.

    Reply
  6. Solving is just so simple just HIDE the unused Sources and that it, the can be there why not, actually yes i want them there because i will know what devices put what sources to what data …
    But if you see all of them you don’t actually know what are the actual one active ? / sync

    Reply
  7. Your post is very useful, I came here because I have problem after I restore my iPhone now I have multiple iPhone and Watch sources, it doesn’t affect the health app, but is anoying if you know what I mean. Do you have any clue to solve it? thanks in advance.

    Reply
    • Hi Cristóbal!

      Multiple (duplicate) sources don’t negatively affect your Health app or its data. I have the same on my iPhone. You could delete unused devices, but it looks like, at least in iOS 11, it would delete the old data too, and you probably don’t want that.

      Reply
      • Thank for your answer! Yeah, I tried deleting but lost my health data and medals. I wish I could be a way to edit that and have just one like is supposed to be.

        Reply

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