Health & Fitness

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Explore the technical aspects of health and fitness features, including sensor data acquisition, health data processing, and integration with the HealthKit framework.

Health & Fitness Documentation

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Best Practices for Continuous Background Biometric Monitoring on Apple Watch
Hello, everyone! I'm seeking some guidance on the App Store review process and technical best practices for a watchOS app. My goal is to create an app that uses HealthKit to continuously monitor a user's heart rate in the background for sessions lasting between 30 minutes and 3 hours. This app would not be a fitness or workout tracker. My primary question is about the best way to achieve this reliably while staying within the App Store Review Guidelines. Is it advisable to use the WorkoutKit framework to start a custom, non-fitness "session" for the purpose of continuous background monitoring? Are there any other recommended APIs or frameworks for this kind of background data collection on watchOS that I should be aware of? What are the key review considerations I should be mindful of, particularly regarding Guideline 4.1 (Design) and the intended use of APIs? My app's core functionality would require this kind of data for a beneficial purpose. I want to ensure my approach is technically sound and has the best chance of a successful review. Any insights or advice from developers who have experience with similar use cases would be incredibly helpful! Thank you!
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346
Aug ’25
Extremely persistent HealthKit read permissions issue
Overview of Issue My implementation of HealthKit is no longer able to read values due to authorization issues (ex. "HealthKitService: Not authorized to read HKQuantityTypeIdentifierHeight. Status: 0"). I have been through every conceivable debugging step including building a minimal project that just requests HealthKit data and the issue has persisted. I've tried my personal as well as Organizational developer teams. My MacOS and Mac Mini. Simulator and personal device. Rechecked entitlements, reprovisioned certificates. This makes no sense. And I have been unable to find anything similar in the Developer forums or documentation. The problem occurs during the onboarding flow when the app requests HealthKit permissions. Even when the user grants permission in the HealthKit authorization sheet, the authorizationStatus for characteristic data types (like Biological s3x and Date of Birth) and quantity data types (like Height and Weight) consistently returns as .sharingDenied. This prevents the app from pre-filling the user's profile with their HealthKit data, forcing them to enter it manually. The issue seems to be environmental rather than a specific code bug, as it has been reproduced in a minimal test case app and persists despite extensive troubleshooting. Minimal test project: https://github.com/ChristopherJones72521/HealthKitTestApp** STEPS TO REPRODUCE Build app, attempt to sign in. No data is imported into the respective fields in the main app. Console logs confirm. PLATFORM AND VERSION iOS Development environment: Xcode Version 16.4 (16F6), macOS 15.5 (24F74) Run-time configuration: iOS 18.5 Relevant Code Snippets Here are the key pieces of code that illustrate the implementation and the problem: 1. Requesting HealthKit Permissions (HealthKitService.swift) This function is called to request authorization for the required HealthKit data types. The typesToRead and typesToWrite are defined in a centralized HealthKitTypes struct. // HealthKitService.swift func requestPermissions(completion: @escaping (Bool, Error?) -> Void) { guard HKHealthStore.isHealthDataAvailable() else { completion(false, HealthKitError.notAvailable) return } let typesToRead: Set<HKObjectType> = [ HKObjectType.characteristicType(forIdentifier: .dateOfBirth)!, HKObjectType.characteristicType(forIdentifier: .biologicals3x)!, HKObjectType.quantityType(forIdentifier: .height)!, HKObjectType.quantityType(forIdentifier: .bodyMass)! ] let typesToWrite: Set<HKSampleType> = [ HKObjectType.workoutType(), HKObjectType.quantityType(forIdentifier: .activeEnergyBurned)! ] healthStore.requestAuthorization(toShare: typesToWrite, read: typesToRead) { success, error in DispatchQueue.main.async { if let error = error { print("HealthKitService: Error requesting authorization: \(error.localizedDescription)") completion(false, error) } else { print("HealthKitService: Authorization request completed. Success: \(success)") completion(success, nil) } } } } 2. Reading Biological s3x (HealthKitService.swift) This function attempts to read the user's biological s3x. The print statements are included to show the authorization status check, which is where the issue is observed. // HealthKitService.swift func readBiologicals3x() async throws -> HKBiologicals3xObject? { guard HKHealthStore.isHealthDataAvailable() else { throw HealthKitError.notAvailable } let s3xAuthStatus = healthStore.authorizationStatus(for: HKObjectType.characteristicType(forIdentifier: .biologicals3x)!) print("HealthKitService: Auth status for Biological s3x: \(s3xAuthStatus.rawValue)") guard s3xAuthStatus == .sharingAuthorized else { print("HealthKitService: Not authorized to read Biological s3x.") throw HealthKitError.notAuthorized } do { return try healthStore.biologicals3x() } catch { print("HealthKitService: Error executing biologicals3x query: \(error.localizedDescription)") throw HealthKitError.queryFailed(error) } } 3. Calling HealthKit Functions During Onboarding (OnboardingFlowView.swift) This is how the HealthKitService is used within the onboarding flow. The requestHealthKitAndPrefillData function is called after the user signs in, and it attempts to read the data to pre-fill the profile form. // OnboardingFlowView.swift func readHealthKitDataAsync() async { print("Attempting to read HealthKit data async...") // ... (calls to HealthKitService.shared.readDateOfBirth(), readHeight(), etc.) do { if let biologicals3xObject = try await HealthKitService.shared.readBiologicals3x() { if self.selectedGender == nil { switch biologicals3xObject.biologicals3x { case .female: self.selectedGender = .female case .male: self.selectedGender = .male case .other: self.selectedGender = .other default: break } } } } catch { print("OnboardingFlowView: Error reading Biological s3x: (error.localizedDescription)") } print("OnboardingFlowView: Finished HealthKit data processing.") } Console Logs Attempting to read HealthKit data async... HealthKitService: Reading Date of Birth... HealthKitService: Current auth status for DOB (during read attempt): 0 HealthKitService: Not authorized to read Date of Birth. Status: 0 OnboardingFlowView: Error reading Date of Birth: The operation couldn’t be completed. (Strike_Force.HealthKitError error 2.) HealthKitService: Reading Height... HealthKitService: Current auth status for HKQuantityTypeIdentifierHeight (during read attempt): 0 HealthKitService: Not authorized to read HKQuantityTypeIdentifierHeight. Status: 0 OnboardingFlowView: Error reading Height: The operation couldn’t be completed. (Strike_Force.HealthKitError error 2.) HealthKitService: Reading Weight (Body Mass)... HealthKitService: Current auth status for HKQuantityTypeIdentifierBodyMass (during read attempt): 0 HealthKitService: Not authorized to read HKQuantityTypeIdentifierBodyMass. Status: 0 OnboardingFlowView: Error reading Weight: The operation couldn’t be completed. (Strike_Force.HealthKitError error 2.) HealthKitService: Pre-read check for Biologicals3x auth status: 1 (Denied) HealthKitService: Reading Biological s3x... HealthKitService: Current auth status for Biological s3x (during read attempt): 1 HealthKitService: Not authorized to read Biological s3x. Status: 1 OnboardingFlowView: Error reading Biological s3x: The operation couldn’t be completed. (Strike_Force.HealthKitError error 2.)
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228
Sep ’25
Old HealthKit samples from WatchOS getting deleted and recreated years later
I have recently come across a couple of odd HealthKit step samples from WatchOS. They represent step data measured in 2022 by my Apple Watch, but they have a creation date ("Date Added to Health") within the past couple of days. These odd samples show a "View All Quantities" button at the bottom of the sample Details page in the Health app on iOS 26 (which I've never seen before); the button leads to a list of many small step quantities, almost as if some older, smaller samples were consolidated into these newer samples. Even weirder is that at least some of these samples seem to be getting re-created repeatedly. For example, I've seen the same sample with a "Date Added to Health" of 9/5/25, then 9/8/25, twice on 9/9/25, and twice on 9/10/25. These samples were originally created by WatchOS 9, and are not being deleted/recreated by any apps on my device. I have only observed it since I updated to the iOS 26 beta (and now the RC); my watch was still running iOS 18 the first time it happened, but it has also happened since my watch was updated to WatchOS 26 beta. I did some debug printing of the odd samples and the normal samples surrounding them for comparison. Here's a normal sample: Sample: 80AC5AC5-CBD7-4581-B275-0C2ACA35B7B4 6 count 80AC5AC5-CBD7-4581-B275-0C2ACA35B7B4, (9.0), "Watch6,1" (9.0) "Apple Watch" (2022-09-15 16:20:14 -0500 - 2022-09-15 16:20:16 -0500) Device: <<HKDevice: 0x10591eee0>, name:Apple Watch, manufacturer:Apple Inc., model:Watch, hardware:Watch6,1, software:9.0, creation date:2022-08-25 18:22:26 +0000> Source revision: <HKSourceRevision name:My Apple Watch, bundle:com.apple.health.EE83959D-D009-4BA0-83A5-2E5A1CC05FE6, version:9.0, productType:Watch6,1, operatingSystemVersion:9.0> Source: <HKSource:0x110588690 "My Apple Watch", bundle identifier: com.apple.health.EE83959D-D009-4BA0-83A5-2E5A1CC05FE6, localDeviceSource: 0, modification date: 2024-01-31 05:49:18 +0000> Date added: 2022-09-15 21:20:16 +0000 Days between end and add: 0 And here's one of the odd samples: Sample: 4982487F-1189-4F16-AB00-61E37818A66D 676 count 4982487F-1189-4F16-AB00-61E37818A66D, (9.0), "iPhone12,1" (16.2) "Apple Watch" metadata: { HKMetadataKeySyncIdentifier = "6:38082859-D9C8-466A-8882-53443B2A2D94:684969619.25569:684970205.31182:119"; HKMetadataKeySyncVersion = 1; } (2022-09-15 16:20:19 -0500 - 2022-09-15 16:30:05 -0500) Device: <<HKDevice: 0x10591ce40>, name:Apple Watch, manufacturer:Apple Inc., model:Watch, hardware:Watch6,1, software:9.0, creation date:2022-08-25 18:22:26 +0000> Source revision: <HKSourceRevision name:My Apple Watch, bundle:com.apple.health.EE83959D-D009-4BA0-83A5-2E5A1CC05FE6, version:9.0, productType:iPhone12,1, operatingSystemVersion:16.2> Source: <HKSource:0x110588640 "My Apple Watch", bundle identifier: com.apple.health.EE83959D-D009-4BA0-83A5-2E5A1CC05FE6, localDeviceSource: 0, modification date: 2024-01-31 05:49:18 +0000> Date added: 2025-09-08 21:11:12 +0000 Days between end and add: 1088 Here's that same odd sample a day later, apparently recreated: Sample: 9E8B12FC-048D-4ECD-BE5B-D387AADE5130 676 count 9E8B12FC-048D-4ECD-BE5B-D387AADE5130, (9.0), "iPhone12,1" (16.2) "Apple Watch" metadata: { HKMetadataKeySyncIdentifier = "6:38082859-D9C8-466A-8882-53443B2A2D94:684969619.25569:684970205.31182:119"; HKMetadataKeySyncVersion = 1; } (2022-09-15 16:20:19 -0500 - 2022-09-15 16:30:05 -0500) Device: <<HKDevice: 0x12f01c4e0>, name:Apple Watch, manufacturer:Apple Inc., model:Watch, hardware:Watch6,1, software:9.0, creation date:2022-08-25 18:22:26 +0000> Source revision: <HKSourceRevision name:My Apple Watch, bundle:com.apple.health.EE83959D-D009-4BA0-83A5-2E5A1CC05FE6, version:9.0, productType:iPhone12,1, operatingSystemVersion:16.2> Source: <HKSource:0x12f0f8230 "My Apple Watch", bundle identifier: com.apple.health.EE83959D-D009-4BA0-83A5-2E5A1CC05FE6, localDeviceSource: 0, modification date: 2024-01-31 05:49:18 +0000> Date added: 2025-09-09 20:53:18 +0000 Days between end and add: 1089 It's worth pointing out some differences between the "normal" and "odd" samples (besides the "View All Quantities" button in the Health app). The recreated "odd" samples have a different Source Revision - the "productType" and "operatingSystemVersion" refer to my iPhone, not the Apple Watch device that actually captured the samples. The odd samples also have metadata keys that don't exist in the other samples - HKMetadataKeySyncIdentifier and HKMetadataKeySyncVersion. Questions I'm hoping someone can help with: What are these samples? Why/how do they have a "View All Quantities" button that shows sub-samples? Is this new to iOS 26? Why are some of the samples getting recreated multiple times?
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146
Sep ’25
Adding workoutEffortScore to HKWorkout
I'm trying to hook into the new workoutEffort score supported in iOS 18, I am collecting this information from users when they submit their workout and trying to add a sample to the HKWorkout in the same manner as I've been adding other samples like bodyweight, calories burned, etc. I'm receiving the error: HKWorkout: Sample of type HKQuantityTypeIdentifierWorkoutEffortScore must be related to a workout I tried adding the samples using HKWorkoutBuilder.add([samples]) as which has been working perfectly for calories burned & bodyweight, but I am receiving the above error for workoutEffortScore As a second approach, I tried adding the sample after I called finishWorkout on the HKWorkoutBuilder and received back the HKWorkout object using HKHealthStore.add([samples], to: HKWorkout) and am still receiving the same error! I don't know otherwise how to relate a sample to a workout, I thought those were the APIs to do so? I'm using Xcode 16.0 RC (16A242) and testing on an iOS 16 Pro simulator
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1.4k
Jul ’25
Stands not detected
I have FB12696743 open since July 21, 2023 and this happened again today. I get home at approx 10 mins after the hour, walk appox 50 ft across my yard, up 5 steps into my house, let the dog out and pace on my deck watching the dog, go back in the house walk around the kitchen while preparing dinner. A total of about 200 ft. I sit down about 35 past the hour and start to eat and at 10 mins to the next our and I get the reminder to stand. On the other side I wake up at 5 mins to hour. Walk 8 steps to the bathroom and successfully achieve the stand for that hour. WHY!?!?!? 😁🤣
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521
Jun ’25
Deprecated: HKCategoryValueMenstrualFlow
We currently use the HKCategoryValueMenstrualFlow enum to determine the type of menstrual flow: light, medium, etc. a user is having. We also use this enum in determining if it's an actual period day. The Problem I see HKCategoryValueMenstrualFlow was recently deprecated but has not been replaced by another data type. Are there plans to replace/update it with another data type? When or at what point in the future will this deprecation cause a problem in my code?
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968
Dec ’24
Can HKWorkoutSession be used for a lone worker protection app for the Apple Watch?
We are developing a mobile app focused on lone worker protection, which does not include any fitness tracking features. We require the use of HKWorkoutSession solely to enable background execution of critical safety-related code. Could you please confirm whether this use of HKWorkoutSession is permitted under App Store Review guidelines, given that our app does not offer fitness or workout-related functionality?
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99
Apr ’25
WatchOS HealthKit HKObserverQuery crashes in background
I have a watchOS app with a connected iOS app using Swift and SwiftUI. The watchOS app should read heart rate date in the background using HKOberserQuery and enableBackgroundDelivery(), send the data to the iPhone app via WCSession. The iPhone app then sends the data to a Firebase project. The issue I am facing now it that the app with the HKObserverQuery works fine when the app is in the foreground, but when the app runs in the background, the observer query gets triggered for the first time (after one hour), but then always get terminated from the watchdog timeout with the following error message: CSLHandleBackgroundHealthKitQueryAction scene-create watchdog transgression: app<app.nanacare.nanacare.nanaCareHealthSync.watchkitapp((null))>:14451 exhausted real (wall clock) time allowance of 15.00 seconds I am using Xcode 16.3 on MacOS 15.4 The App is running on iOS 18.4 and watchOS 11.4 What is the reason for this this issue? I only do a simple SampleQuery to fetch the latest heart rate data inside the HKObserverQuery and then call the completionHandler. The query itself takes less than one second. Or is there a better approach to read continuously heart rate data from healthKit in the background on watchOS? I don't have an active workout session, and I don't need all heart rate data. Once every 15 minutes or so would be enough.
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427
Oct ’25
How to save medication dose with new HealthKit apis?
The recent WWDC presentation on HealthKit demonstrated how to associate side effects with a medication dose using HKObjectType.categoryType(forIdentifier:) and HKCategorySample, a subclass of HKObject. There also appears to be an object type specifically for medication doses: HKMedicationDoseEventType, accessible via HKObjectType.medicationDoseEventType(). However, there’s no corresponding public subclass of HKObject that supports this identifier. The most relevant class, HKMedicationDoseEvent, exists but has an inaccessible initializer. Is there currently a supported way to use HKMedicationDoseEventType, or is this functionality not yet available? https://developer.apple.com/videos/play/wwdc2025/321/
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103
Jun ’25
AppIntent, StartWorkoutIntent, and Siri
I'm a bit confused as to what we're supposed to be doing to support starting a workout using Siri in iOS/watchOS 26. On one hand, I see a big push to move towards App Intents and shortcuts rather than SiriKit. On the other hand, I see that some of the things I would expect to work with App Intents well... don't work. BUT - I'm also not sure it isn't just developer error on my part. Here are some assertions that I'm hoping someone more skilled and knowledgable can correct me on: Currently the StartWorkoutIntent only serves the Action button on the Watch Ultra. It cannot be used to register Shortcuts, nor does Siri respond to it. I can use objects inherited from AppIntent to create shortcuts, but this requires an additional permission to run a shortcut if a user starts a workout with Siri. AppIntent shortcuts requires the user to say "Start a workout in " - if the user leaves out the "in " part, Siri will not prompt the user to select my app. If I want to allow the user to simply say "Start a Workout" and have Siri prompt the user for input as to which app it should use, I must currently use the older SiriKit to do so. Are these assertions correct - or am I just implementing something incorrectly? Using the latest Xcode 26 beta for what it is worth.
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150
Aug ’25
Sleep Score API access
New in iOS 26 and WatchOS 26 is a Sleep Score calculation for users based on Duration, Bedtime and Interruptions. Unfortunately I can't find any APIs for developers to tap into this metric. Yes, in theory it's all created off the same Sleep Analysis data already available with HealthKit but that makes it very hard to recreate in our apps. If the numbers don't match up exactly, users will understandably complain. Can anyone confirm that this is the case and I've not missed a Sleep Score API? I'll then file feedback. Hopefully this doesn't go the way of Heart Rate Zones where the Apple Watch iPhone app has generated them for years and provided no way for third party apps to access these values (yes many feedbacks provided previously).
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229
Sep ’25
Icon Composer - Icon not visible in Fitness App
Hi everyone, we’re developing an app that lets users export selected bike rides to the HealthKit ecosystem. We created our app icon using the Apple Icon Composer and referenced the composer file in Xcode. Everything works fine, except that the logo doesn’t appear correctly in the Fitness app. Has anyone experienced this issue or knows how to fix it?
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123
Nov ’25
Can a 3rd party app use WorkoutKit to store interval details?
I am the developer of a workout app that allows users to create interval programs (e.g. Warm Up, Fast, Cool Down). It is possible for me to store the data for the intervals along with the workout in the Health system by using WorkoutKit (or any other method)? My aim is to make it so that the Fitness app shows the interval details when users view workouts created by my app. Thanks in advance.
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74
Nov ’25
Sleep Analysis inBed sample not recorded on Apple Watch in iOS 18
In this link, Apple states we can know when a user is in bed vs sleeping and compare their quality of sleep by it. Only, in iOS 18, Apple no longer reports inBed time samples for the Apple Watch. I get why they stopped doing this for the phone, but why the watch? Bug? My app was using the inBed times for this very purpose and now only works for Garmin and Oura who still report inBed times. https://developer.apple.com/documentation/healthkit/hkcategoryvaluesleepanalysis
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1.4k
Dec ’24
healthStore.workoutSessionMirroringStartHandler never called
I'm trying to run this example project: https://developer.apple.com/documentation/HealthKit/building-a-multidevice-workout-app When I run it on my device (iPhone 16 Pro and Apple Watch Ultra 2) I get this error: -[SPRemoteInterface _appRecoverAnyExtendedRuntimeSession:]_block_invoke:4350: Got no sessions back from -[CSLSSessionService existingRunningSessions:] or -[CSLSSessionService existingScheduledSessions:] after receiving a PUICInitializeSessionServiceAction I start the workout from my phone, which successfully starts the workout on the watch. But this callback is never triggered on the phone: healthStore.workoutSessionMirroringStartHandler { // not happening } This makes it difficult to learn the mirroring workout technique. I'm using Xcode 16.3 and Mac OS 15.4.1. Any help appreciated!
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87
Apr ’25
What’s the expected frequency of HealthKit enableBackgroundDelivery: HKCategoryTypeIdentifier.sleepAnalysis
Hello, I have enabled HealthKit background delivery for sleep analysis samples: private func setupSleepDataBackgroundDelivery() { if let sleepType = HKObjectType.categoryType(forIdentifier: HKCategoryTypeIdentifier.sleepAnalysis) { healthStore.enableBackgroundDelivery(for: sleepType, frequency: .immediate) { (success, error) in } } } In general, this function works. But I would love to know what the limitations / expected delivery delay for frequency: .immediate is. The documentation is only very vague about this and specifies that some sample types such as steps are only delivered once per hour. But how about sleep data? Is this expected to be delivered immediately once available on iPhone? Thanks a lot for your help!
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236
Sep ’25
Evolution of HealthKit workout API on iOS 26 and iPadOS 26 - HKLiveWorkoutDataSource and built-in Sensor Support
I am very happy to see that HealthKit with OS26 is bringing HKLiveWorkoutDataSource to iOS and iPadOS. I have been replicating a similar type for the last several years for users that only have an iPhone. I did notice that the data types that the different platform data sources collect automatically is different. That makes sense if you think exclusively about what the device can actually capture. Bluetooth HRM is the only Bluetooth SIG profile that is out-of-the-box supported for Apple Health on iOS and iPadOS (right?). Whereas watchOS 10 got all of the cycling sensors (woohoo!). It would be great if the types to collect were the same across platforms even if the device couldn't collect the data now, because then in the future when / if new sensor support is added, it will be transparent to developers. Fantastic. Easier life as an indie / third party developer. At least that is the idea. And yes, I know I can also write Core Bluetooth code and roll my own SIG implementation for the cycling profiles, but Apple already has this code in one os, 'just copy it, it will be easy'. I know that isn't the reality especially against the new ASK framework, but one can hope and dream right? Imagine how many more apps would contribute that data if it was supported out of the box. An alternative, GitHub is a great place for Apple to share their Core Bluetooth implementation of the SIG profiles :). Just another thought. Here are some feedbacks related to this: FB17931751 - HealthKit: Add built-in support for cycling sensors on iOS and iPadOS - copy paste the code from watchOS. It will be easy they said (June 2025) FB12323089 - CoreBluetooth / Health / Bluetooth Settings: Add support for cycling sensors announced in watchOS 10 to iOS and iPadOS 17 (June 2023) FB14311218 - HealthKit: Expected outdoor cycling to include .cyclingSpeed quantity type as a default HKLiveWorkoutDataSource type to collect (July 2024) FB14978701 - Bluetooth / HealthKit / Fitness: Expose information about the user specified for Apple Watch paired Cycing Speed Sensor like isConnected and wheelCircumference values (August 2024) FB18402258 - HealthKit: HKLiveWorkoutDataSource should collect same types on iOS and watchOS even if device cannot produce data today (June 2025) FB14236080 - Developer Documentation / HealthKit: Update documentation for HKLiveWorkoutDataSource typesToCollect for which sample types are automatically collected by watchOS 10 and 11 (July 2024) Tangentially related: FB10281304 - HealthKit: Add HKActivityTypes canoeBikeRun and kayakBikeRun (June 2022) FB10281349 - HealthKit: Add HKActivityType walkCanoeWalk and walkKayakWalk (June 2022) FB7807993 - Add HKQuantityTypeIdentifier.paddleDistance for canoeing, kayaking, etc type workouts (June 2020) FB12508654 - HealthKit / Settings / Bluetooth / Workouts: Cycling sensor support doesn't allow for 'bike selection' in use case of multiple bikes and multiple sensors (borrow a bike to ride together) - production usability issue (July 2023)
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141
Jun ’25