Use HealthKit to enable your iOS and watchOS apps to work with the Apple Health app.

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HKObserverQuery stops delivering updates in background on watchOS 26
Hello, I’m building a health-related app for both watchOS and iOS, which needs to monitor certain health data (e.g., heart rate, active energy). Before updating to watchOS 26, the queries worked reliably without any issues. However, after adapting to watchOS 26, some users have reported that health data updates stop being delivered. What I’ve observed: HKObserverQuery with enableBackgroundDelivery is set up normally. On WatchOS 26, the query sometimes stops delivering updates entirely after a certain point, and once an update is missed, it may stop delivering further updates completely. Restarting the Apple Watch temporarily restores delivery, but the problem reoccurs after some time. This makes background health data monitoring unreliable for my app. Here’s a simplified version of the code we are using: guard let heartType = HKObjectType.quantityType(forIdentifier: .heartRate) else { return } let query = HKObserverQuery(sampleType: heartType, predicate: nil) { query, completionHandler, error in if let error = error { logEvent("Observer error: \(error.localizedDescription)") return } logEvent("Heart rate changed") MyNotificationManager.shared.sendNotification() // Send a local notification completionHandler() } healthStore.execute(query) healthStore.enableBackgroundDelivery(for: heartType, frequency: .hourly) { success, error in if success { logEvent("Background heart rate delivery enabled") } else { logEvent("Failed to enable background heart rate delivery: \(error?.localizedDescription ?? "Unknown error")") } } Could you please clarify: Is this a known issue with HKObserverQuery and enableBackgroundDelivery on watchOS 26? Are there any recommended workarounds or best practices to ensure continuous background delivery of health data? Thank you in advance for your help.
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508
Oct ’25
Guidance / Documentation on iOS 18.6.1 Blood Oxygen Saturation
Are there any HealthKit related changes to be aware of in the new update that enables SPO2 / Blood Oxygen Saturation measurements on certain Apple Watch models within the US? I’m aware of processing happening on the phone…. But beyond that: Does this mean values are then saved to Apple Health? Do these models still take background SPO2 measurements in the same way as other models do? Are these values then visible in third party iOS apps as normal through HealthKit? Do these values sync back to the paired Apple Watch HealthKit store for third party apps to access on the Watch? For reference I have an iOS and WatchOS app that, amongst other features, provides the ability to see your SPO2 values in the Watch app, complications and in the iOS app.
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258
Sep ’25
Incorrect Step Count from Apple HealthKit Data
Hi, i'm trying to get the number of step counts a person has taken. I decided to pull the data from health kit and the number of steps are incorrect. Come to find out apple health recommends an app called pedometer++ for the number of steps counted and after testing I realized that they are getting the correct number of steps a person is taking. How can I pull the correct number of steps a person has taken? I want to be able to merge the data from watch and phone to make sure we are getting the correct number of steps but not double counting the steps either. any guidance on this would be appreciated! Here's the code snippet that i'm using right now: permissions: { read: [AppleHealthKit.Constants.Permissions.StepCount], write: [], }, }; AppleHealthKit.initHealthKit(permissions, error => { if (error) { console.log('Error initializing HealthKit: ', error); return; } else { dispatch(setAllowHealthKit(true)); getHealthKitData(); console.log('HealthKit initialized successfully'); } }); const getHealthKitData = async () => { try { const today = new Date(); const options = { startDate: new Date(today.setHours(0, 0, 0, 0)).toISOString(), endDate: new Date().toISOString(), }; const steps = await new Promise((resolve, reject) => { AppleHealthKit.getStepCount(options, (error, results) => { if (error) reject(error); resolve(results?.value); }); }); setStepsCount(steps); } catch (error) { console.error('Error fetching HealthKit data:', error); } };
6
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197
Jul ’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
5
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1.4k
Jul ’25
Sleep Samples sum off by 2 minutes
Hi everyone! I'm trying to get the total sleep time for a given day, but users report that there's a difference between what my app reports and what the Apple Health app reports. In particular, we're off by 2 minutes less on average. What we're doing is: Get all the samples that are either core, deep, rem or unspecified Cut-off time at 3 PM previous day Merge overlapping intervals Add all the remaining intervals For debugging purposes I'm storing and sending all the raw samples to a server, and I have run tests and I don't find anything wrong. It looks like the number we come up with is correct according to our own rules. I wonder, how is Apple adding up all the samples to arrive at a number that's slightly off to our number. Any insight would be appreciated. Thanks.
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198
Mar ’25
Fitness app not now show saved routes
When I set the distanceFilter = 5 (5 meters) in the GPS CLLocationManager I can't display the workout routes in the Apple Fitness app after writing the recorded GPS data to HealthKit via HKWorkoutRouteBuilder. The smaller distanceFilter, Fitness will displays the route. Should I consider setting up a small distanceFilter when developing a workout app on watchOS?
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140
Jul ’25
Integrating Apple Fitness+ Workouts – How to Retrieve Metadata?
Platform & Version: iOS Version: 18.3.1 Development Environment: Xcode 16.2, macOS 14.6.1 Description of the Issue: We're exploring ways to better integrate Apple Fitness+ workouts into our app. We've noticed that some third-party apps, such as Strava and HealthFit, now display Fitness+ workout details, including the title, trainer, and an image. I’ve been investigating how this is possible, and the only relevant change I’ve found is that HKMetadataKeyAppleFitnessPlusCatalogIdentifier is now being set for Fitness+ workouts. However, I can’t find any public API or official documentation that explains how to use these identifiers to retrieve the associated workout details. Question: Is there an official API available to fetch metadata for Fitness+ workouts using these identifiers? Or are these third-party apps potentially accessing private APIs? If no API exists, is the only option to create a manual mapping of these identifiers—something that seems impractical given the constantly evolving Fitness+ workout catalog? Any guidance on this would be greatly appreciated. Thanks!
4
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632
Feb ’25
Recording a HeartbeatSeries
I need to be able to create and store a HeartbeatSeries for a given time-period from an Apple Watch, to then retrieve that data from HealthKit to be processed. I have working code which allows me to begin a workout session, which is being used to determine how long a session has been running for. I also have working code for retrieving HeartbeatSeries data from HealthKit. The issue is that no HeartbeatSeries data is being stored into HealthKit as a result of the workout session running. Whether that session is running for as little as 30 seconds or as long as 20 minutes, nothing is stored. However, when I use the the Apple "Meditation" app (formerly known as "Breathe"), I can query HealthKit afterwards and retrieve a list of individual heartbeat timings during that 2 minute period. Therefore, it IS possible to store a HeartbeatSeries from within an app on the Apple Watch. What I would like to know is, how can I use the pulse sensor built-in to the Apple Watch to be able to record a HeartbeatSeries similar to how the Meditation app does it.
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115
Mar ’25
How to run HKWorkoutSession on watch without affecting activity rings?
My research group is using watch sensors (accelerometers, gyroscopes) to track wrist motion to detect and measure eating. https://cecas.clemson.edu/ahoover/bite-counter/ We are running an HKWorkoutSession on the watch so that the app can run for an extended period of time (up to 12 hr) and continue to sense and process motion data. Our app is adding to the activity rings, making it look like the user is exercising the entire time our app is running. Is there a method to prevent our app from contributing to the activity ring measures?
3
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128
Apr ’25
UIScene.ConnectionOptions.shouldHandleActiveWorkoutRecovery Missing?
According to the WWDC25 Presentation Track workouts with HealthKit on iOS and iPadOS, there is supposed to be a new property for restoring an active workout after a crash on iOS/iPadOS. The developer documentation also supports this. However, this property does not seem to exist in the latest Xcode 26 beta, even in projects targeting iOS 26.0 as the minimum version. Am I missing something? Has this property not been made available yet? It is actually looking like all of the new iOS 26.0 properties are missing UIScene.ConnectionOptions on my system.
3
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182
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).
3
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228
Sep ’25
How to accurately query HKWorkout segment data
Hello, In my application, I need to obtain precise workout segment data from HKWorkout in order to calculate per-kilometer metrics such as heart rate and pace. My current approach is: 1.Use HKWorkout to fetch the associated HKWorkoutEvents. 2.Take the end time of one event as the start time of the next event to derive per-kilometer segment ranges. The issue I’m facing: •If a user sets Apple Watch to notify every 5 kilometers, then at 5 km, 10 km, 15 km, etc., I see overlapping event times. •From the HKWorkoutEvents data alone, I cannot distinguish between events that represent “per-kilometer splits” and those that represent “5-kilometer notifications.” •As a result, my per-kilometer heart rate and pace calculations can be inaccurate. My question is: Is there a recommended way to reliably differentiate per-kilometer splits from custom distance notifications and ensure accurate segment data retrieval? For example, should I instead reconstruct segments using HKWorkoutRoute and distance samples, rather than relying on HKWorkoutEvents? STEPS TO REPRODUCE 1.On Apple Watch, start an Outdoor Run using the Workout app. 2.In workout notifications, set distance alerts to every 5 kilometers. 3.During the run, when reaching 5 km, 10 km, 15 km, etc., the watch triggers notifications. 4.Query the corresponding HKWorkout from HealthKit and inspect its HKWorkoutEvents. 5.Notice that some event start times are duplicated, and it is unclear which events represent “per-kilometer splits” and which represent “5-kilometer notifications.” Expected Result: Be able to differentiate between per-kilometer splits and custom distance alerts, so that heart rate and pace per kilometer can be calculated accurately. Actual Result: The HKWorkoutEvents data contains duplicated event times without a way to distinguish event types, leading to inaccurate per-kilometer statistics.
3
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128
Oct ’25
HKAnchoredObjectQuery updateHandler stops working with error
Hi! I am using the HKAnchoredObjectQuery to first get a snapshot of the initial results, and then trigger an updateHandler. I need to handle the initial results and the updates separately, which is why I implemented two completions. When I test the code, it works for a while. New and deleted samples trigger the updateHandler. However, after a while there appears an error: [connection] nw_read_request_report [C2] Receive failed with error "Software caused connection abort" Followingly, the updateHandler will stop getting triggered when I add updates in Apple health. Anyone have experience with this? func getMostRecentSample(for sampleType: HKSampleType, anchorKey: String, completion: @escaping (HKQuantitySample?, Error?) -> Swift.Void, updateHandler: @escaping (HKQuantitySample, Error?) -> Swift.Void) {     // If it is the first initialization, anchor is passed as nil     var anchor: HKQueryAnchor? = nil // Check for previous saved anchor in userdefaults     if UserDefaults.standard.object(forKey: anchorKey) != nil {       let data = UserDefaults.standard.object(forKey: anchorKey) as! Data       do {         guard let newAnchor = try NSKeyedUnarchiver.unarchivedObject(ofClass: HKQueryAnchor.self, from: data) else {           print("Could not parse anchor to HKQueryAnchor type")           return         }         anchor = newAnchor       } catch {         print("Error retreiving anchor from UserDefaults")       }     }     let query = HKAnchoredObjectQuery(type: sampleType,                      predicate: nil,                      anchor: anchor,                      limit: HKObjectQueryNoLimit                       ) { (query, samplesOrNil, _, newAnchor, errorOrNil) in       guard let samples = samplesOrNil as? [HKQuantitySample] else {         fatalError("*** An error occurred during the initial query: \(errorOrNil!.localizedDescription) ***")       }       if let anchor = newAnchor {         do {           let data = try NSKeyedArchiver.archivedData(withRootObject: anchor as Any, requiringSecureCoding: false)           UserDefaults.standard.set(data, forKey: anchorKey)         } catch {           print("Error retreiving anchor from UserDefaults")         }       }       completion(samples.last, nil)     }           // Setting up long-running query     query.updateHandler = { (query, samplesOrNil, _, newAnchor, errorOrNil) in       guard let samples = samplesOrNil as? [HKQuantitySample] else {         fatalError("*** An error occurred during an update: \(errorOrNil!.localizedDescription) ***")       }       if let anchor = newAnchor {         do {           let data = try NSKeyedArchiver.archivedData(withRootObject: anchor as Any, requiringSecureCoding: false)           UserDefaults.standard.set(data, forKey: anchorKey)         } catch {           print("Error retreiving anchor from UserDefaults")         }       }       if let sample = samples.last {         updateHandler(sample, nil)       }     }     self.healthStore.execute(query)   }
2
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1.2k
Mar ’25
HKWorkoutSession.sendToRemoteWorkoutSession doesn't report success or failure
We are seeing an issue where sending data using the asynchronous method HKWorkoutSession.sendToRemoteWorkoutSession(data: Data) will never return in some cases (no success nor failure). This issue is happening for roughly 5% of Workouts started and will stay broken for the whole workout. The other 95% of the workouts, the connection works flawlessly. This happens on both watchOS 10 and 11, and with phones running iOS 17 or 18. The issue is quite random and not reproducible. Our app has thousands of workouts a day that use the workout session workout data send, with constant messages being send every few seconds. In some of those 5% cases the "sendToRemoteWorkoutSession" will throw way later, like 30+ minutes later, if the watch app is awake long enough to capture a log of a failure. Our code uses the same flow as in the sample project: https://developer.apple.com/documentation/healthkit/workouts_and_activity_rings/building_a_multidevice_workout_app Here is some sample code, which is pretty simple. Setup code: let workoutSession = try HKWorkoutSession(healthStore: healthStore, configuration: configuration) workoutSession.delegate = self activeWorkoutSession?.startMirroringToCompanionDevice { success, error in print("Mirroring started on companion device: \(success), error: \(error)") } workoutSession?.prepare() then later we send data using the workout session: do { print("Will send data") try await workoutSession.sendToRemoteWorkoutSession(data: data) print("Successfully sent data") // This nor the error may be called after waiting extensive amounts of time } catch { print("Failed to send data, error: \(error)") // This nor the success may be called after waiting extensive amounts of time } So far, the only fix is to restart the phone and watch at the same time, which is not a great user experience. Is anyone else seeing this issue? or know how to fix this issue?
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605
1w
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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1
967
Dec ’24
Read Workout Effort Scores
Is there documentation on how to read workout effort scores from a HealthKit workout? I'm interested in reading workoutEffortScore and estimatedWorkoutEffortScore. I have not been successful trying to read them using the same method that I do other workout HKQuantityTypes (heartRate, stepCount, etc). I'm using Swift and I do have authorization for those types requested and granted. I have found documentation on setting these values (https://developer.apple.com/forums/thread/763539) but not reading them. Thank You
2
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936
Jan ’25
Workouts fail to register on Fitness activity rings
Hello, My app syncs workout data from a third-party device and records workouts with HealthKit as follows: let builder = HKWorkoutBuilder(healthStore: healthStore, configuration: hkConf, device: hkDevice) try await builder.beginCollection(at: startDate) try await builder.addSamples(samples) try await builder.endCollection(at: endDate) let workout = try await builder.finishWorkout() let workoutRouteBuilder = HKWorkoutRouteBuilder(healthStore: healthStore, device: hkDevice) try await workoutRouteBuilder.insertRouteData(filteredLocations) try await workoutRouteBuilder.finishRoute(with: workout, metadata: nil) However, I’m encountering two issues: The workouts appear in Apple Fitness but do not contribute to the activity rings. The workout includes a route (visible in the raw workout data in Apple Health) but does not display on Apple Fitness. Is there any way to fix this? I’d appreciate any suggestions you might have. __
2
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767
Jan ’25
Extended Runtime Session vs HKWorkoutSession Issues
I am working on an Apple Watch companion app to an existing live iOS app. I am utilizing the heart rate tracking for an active 'self-care' sauna session. I say self-care in quotes because it's more self-care than a workout activity, but it is closely blurring the lines between the two. I have come to understand that if a session truly isn't a workout, then you should not use workoutSession.startActivity. However the app needs to function entirely like a workout would. This is not a meditation application. Sauna is actually just one of many activity types supported in the app. I have tried using extended runtime session, and there have been numerous issues with doing so. It is not nearly as robust for the user. For example, the active session is not prioritized by the watch's CPU. Now playing is no longer functional. Heart rate is far more inconsistent, and this variable is as critical as if it were in a workout. I have tried using HKWorkoutSession, however I worry the app will be rejected by doing so. This method works most accurately to collect the right data for the user, and prioritizes system resources as expected. The app can be moved to the background as expected and continue to communicate with the iOS app. What is the best way to move forward here. It almost feels like I am operating in a grey area with no real solution in place. Any assistance is greatly appreciated as we would like to follow all guidelines while producing a high quality experience for our users.
2
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813
Jan ’25