Dear Apple Developer Support,
I am writing to request assistance with an ongoing issue I'm encountering while developing an iOS application that utilizes HealthKit to fetch heart rate data.
My goal is to display near real-time heart rate updates continuously same as displaying in the Apple Watch , I want to show in the iPhone Mobile Application for fitness related. I have implemented the following approaches:
- HKSampleQuery with a Timer: I've set up a timer to periodically fetch the latest heart rate data.
Despite these efforts, I'm consistently facing the following problems:
- Delayed Updates: The heart rate data displayed in the app often doesn't reflect the current heart rate being measured by the Apple Watch. There seems to be a significant synchronization delay.
- Inconsistent Background Updates: Background updates, even with background app refresh enabled, are not reliable. The app often only updates when brought to the foreground or after being killed and relaunched.
- Entitlements: The com.apple.developer.healthkit.background-delivery entitlement error is missing.
I have thoroughly reviewed Apple's HealthKit documentation, implemented best practices for HealthKit integration, and verified that all necessary permissions are properly configured.
I understand that HealthKit may not be designed for true real-time data, but the current level of delay and inconsistency is making it difficult to provide a useful user experience.
Could you please provide guidance on whether achieving near real-time heart rate updates continuously in an iOS app using HealthKit is possible? If so, what are the recommended strategies and best practices to overcome these limitations?
I have also tested the application on physical devices with Apple Watch, enabled background app refresh, granted permissions, and referred to HealthKit documentation.
I would appreciate any insights or suggestions you can offer to help resolve this issue.
Thank you for your time and assistance.
Sincerely,
Venu Madhav
Delayed Updates: The heart rate data displayed in the app often doesn't reflect the current heart rate being measured by the Apple Watch. There seems to be a significant synchronization delay.
This is pretty much as-designed because:
-
Your HealthKit queries on iOS only return or observe what the iOS HealthKit store currently has. Data that exists on your Apple Watch but isn't synchronized to the paired iPhone is not available to your iOS app.
-
The HealthKit store synchronization between an iPhone and its paired Apple Watch is not real-time, and there is no API that can speed up the pace. Some actions, like bringing a HealthKit-enabled app to the foreground, can trigger a synchronization, but that is completely up to the system.
To achieve your goal, I can think of the following options:
-
Creating a watch app that uses
HKAnchoredObjectQuery
to observe the update from the watchOS HealthKit store, and sends the update to your iPhone app using Watch Connectivity. -
If your app is a workout app, consider mirroring a workout to your iOS app, as discussed in Building a multidevice workout app.
Best,
——
Ziqiao Chen
Worldwide Developer Relations.