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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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?
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98
Apr ’25
HealthKit Authorization Requests Immediately Denied in iOS 18.5 - No Permission Dialog Shown
I am experiencing a critical issue with HealthKit authorization in iOS 18.5 where requestAuthorization() calls are immediately denied without showing the user permission dialog. Problem Description: HealthKit authorization requests immediately return .sharingDenied status No system permission dialog is displayed to the user Authorization status changes from .notDetermined to .sharingDenied in <0.1 seconds This occurs for all HealthKit data types (step count, heart rate, sleep analysis, etc.) Technical Details: iOS Version: 18.5 (22F76) Xcode Version: 16F6 Device: iPhone (tested on both simulator and physical device) Bundle IDs tested: com.hereforyou.test2024, com.hereforyou.app Entitlements: com.apple.developer.healthkit = true Code Implementation: let healthStore = HKHealthStore() let stepType = HKObjectType.quantityType(forIdentifier: .stepCount)! // Status before request: .notDetermined try await healthStore.requestAuthorization(toShare: [], read: [stepType]) // Status after request: .sharingDenied (immediate, <0.1 seconds) Evidence this is not a code issue: Other HealthKit apps from App Store work correctly on the same device Proper entitlements are configured and verified HKHealthStore.isHealthDataAvailable() returns true Same code worked in previous iOS versions Multiple Bundle IDs tested with same result Expected Behavior: System should display HealthKit permission dialog allowing user to grant/deny access Actual Behavior: Authorization is immediately denied without user interaction Steps to Reproduce: Create new iOS app with HealthKit entitlements Call requestAuthorization() for any HealthKit data type Observe immediate denial without permission dialog Is this a known issue in iOS 18.5? Are there any workarounds or timeline for a fix? Best regards
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83
Jun ’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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106
4d
internal healthkit error: "Unable to invalidate interval: no data source avallable"
we are seeing what appears to be an internal healthkit error appearing in our app.  not sure if it's connected, but we've mostly seen it reported on devices running ios 16.  even though our app's primary language is japanese, and in all reported occurrences the app was running in japanese, the error message itself appears in english.  searching the error string on the web yields surprisingly few results (including only two mentions on this forum that i could find, neither of which seemed relevant).  this would seem to suggest that it's coming from something deep inside healthkit, since the error message is not localized.  in all reported cases, the user had recently upgraded to a new iphone.  in most cases, the problem only occurs on the new device even though everything had been working correctly prior to the upgrade.  the error occurs when the app is unable to read step count data from healthkit. we have confirmed that the app has been granted access permissions to all health data via os settings.  we've also tried having the user toggling those settings off, then back on, rebooting the device, deleting and reinstalling the app, etc., to no avail. the error message is "Unable to invalidate interval: no data source avallable." we'd appreciate it if anyone can shed more light on this issue. thanks!
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1.7k
Oct ’24
Workout Effort Scores
Is there anywhere that describes in detail how third party workout apps can use the new effort score functionality? I can't see much in the documentation or any of the WWDC videos. In particular it would be useful to know if an effort score is automatically calculated for workouts created with third party apps? It doesn't seem to happen but some people say it takes weeks / months before watchOS starts calculating it for third party apps. If it doesn't happen automatically then how can the app set it? I tried the new relateWorkoutEffortSample API but that didn't work for me (see https://developer.apple.com/forums/thread/763539). If I could get it working then how should I determine a default effort score based on the workout metrics? Is that something that the app should do? If so then it would be good to be consistent with watchOS so some idea of how that is calculating effort scores would be useful. Sorry for all the questions, especially if there is an article in the documentation or a video that I have missed.
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2.1k
Oct ’24
HealthKit returns different values depending on the OS the request is made on
Hi, I've had trouble for a while now with HealthKit giving me different values if I make the request on iOS and WatchOS. I am using the exact same method on both with the same parameters but I get vast differences in the results. The code I am using to call HealthKit on both devices is: let dateRange = HKQuery.predicateForSamples(withStart: Date().removeMonths(numberOfMonths: 1), end: Date().endOfDay()) let predicate: NSPredicate predicate = NSCompoundPredicate(type: .and, subpredicates: [dateRange]) let query = HKStatisticsQuery(quantityType: HKQuantityType(.stepCount), quantitySamplePredicate: predicate, options: .cumulativeSum) { _, result, error in if error != nil { //print("Error fetching step count, or there is no data: \(error.localizedDescription), \(startDate) -> \(endDate)") onComplete(0) return } if let result, let sum = result.sumQuantity() { let stepCount = sum.doubleValue(for: HKUnit.count()) DispatchQueue.main.async { onComplete(Int(stepCount)) } } } healthStore.execute(query) }
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1k
Jun ’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!
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599
Feb ’25
How to get the same swimming distance like in the Fitness app
Hello Apple Community, What does approach use the Fitness app for swimming distance calculation per set (segment)? I've tried 2 options but all of them have different values than in the Fitness app. Calculation like that: pool length * number of laps = swimming distance BUT the Fitness app sometimes shows other values for distance per set (segment). Fetch all distance values via HKQuantityTypeIdentifier.distanceSwimming (HKSampleQuery`) and than try to match distance values with set (segment) duration. Again I got other values for swimming distance per set, values are bigger than in the Fitness app. let healthStore = HKHealthStore() let distanceType = HKQuantityType.quantityType(forIdentifier: HKQuantityTypeIdentifier.distanceSwimming)! let predicate = HKQuery.predicateForSamples(withStart: startDate as Date, end: endDate as Date?, options: .strictStartDate) let query = HKSampleQuery(sampleType: distanceType, predicate: predicate, limit: HKObjectQueryNoLimit, sortDescriptors: [.init(keyPath: \HKSample.startDate, ascending: true)], resultsHandler: { (query, results, error) in if let error { Logger.e("\(error)") continuation.resume(returning: nil) } continuation.resume(returning: results) }) healthStore.execute(query) Is it possible to get the same swimming distance like in the Fitness app per set via HealthKit?
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91
Mar ’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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1.3k
Jul ’25
Workout mode drains battery heavily
I am building a watchOS app with iOS companion app. The watch app needs to track the heart rate during the night or while user is sleeping. And the desired frequency of measurement is 0.2Hz (every 5 seconds) For this I am using the HKWorkout mode with mindAndBody session. While it works fine, One of the main issue is: after about 6-7 hours of usage, the battery on the watch drains between 40% (Series 9) and 100% (series 7, I think) My questions: Are there any other option to track user's heart rate without workout, while the app could be in background? Another side effect of this workout mode is, Even if we choose not to save the workout in HealthKit, the Activity rings gets populated by this mindAndBody session, which makes it when the user is waking up, the bar is already full, This is not desired. Is there any option to specify for ActivityRing skips this? Highly appreciate any help in advance. Cheers - Prakash
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1.1k
Dec ’24
Is sleep analysis data available in Smart Alarms?
I am working on a Smart Alarm app for Watch OS. When testing on an Series 10 watch, I am successfully able to read heart rate data in the ExtendedRuntimeSession. However, although the calls succeed, the sleep analysis data is all 0. The app successfully gets authorization for: [HKQuantityType(.heartRate), HKObjectType.categoryType(forIdentifier: .sleepAnalysis)!] I have read that sleep data is not available for less than an hour time period. The Smart Alarm extended session has a 30 minute limit. Does that mean it is not possible to read sleep analysis data in a Smart Alarm extended session? Thank you!
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888
Jan ’25
Healthstore read only in objective-C ?
I have an App in objective-c that is using Health data (walk/run, cycling) to give advice to users . I do not want/need to write any data in the Healtkit. If i do (with the 3 values in the plist / .info : self.healthStore requestAuthorizationToShareTypes:nil readTypes:readDataTypes My request crashes. *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Must request authorization for at least one data type' *** First throw call stack: ( 0 CoreFoundation 0x00000001804b910c __exceptionPreprocess + 172 1 libobjc.A.dylib 0x0000000180092da8 objc_exception_throw + 72 2 CoreFoundation 0x00000001804b901c -[NSException initWithCoder:] + 0 3 HealthKit 0x000000019da034d4 -[HKHealthStore _validateAuthorizationRequestWithShareTypes:readTypes:] + 92 4 HealthKit 0x000000019da03670 -[HKHealthStore requestAuthorizationToShareTypes:readTypes:shouldPrompt:completion:] + 292 BUT in swift : healthStore.requestAuthorization(toShare: nil, read: readTypes) is working, présents only my 2 datas to read... in the same IOS , same phone without crashing. What is the difference ? Nil object in objective-c and Nil object in swift are not the same ? how do i make readonly requests in objective C ?
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365
Mar ’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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167
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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104
Jul ’25
HKLiveWorkoutBuilder only reporting heart rate - No other measurements
I'm using Healthkit with the following H/W specs: Apple Watch, series 8, OS: 10.6.1 (21U580) iPhone 11 Pro, OS: 17.6.1 Mac Studio M1 Xcode ver: 16.0 (16A242d) I am trying to get Apple Watch to report heart rate, HRV, respiratory rate, and body temperature using Healthkit's HKLiveWorkoutBuilder implementing HKLiveWorkoutBuilderDelegate's workoutBuilder method. However, the only reported value that is found from the workoutBuilder method's collectedTypes (a Set of HKSampleType objects) is HKQuantityTypeIdentifierHeartRate. Nothing for HRV, respiratory rate, or body temperature. All entitlements are set up, the plist filled in, and capabilities in place. Not sure why only the heart rate is reported from the watch but nothing else. I've scoured StackOverflow, Apple developer forums, even ChatGPT but none of the solutions work. Any help most appreciate! The model code is: import Foundation import HealthKit class WatchModel: NSObject, HKLiveWorkoutBuilderDelegate, HKWorkoutSessionDelegate { private let healthStore = HKHealthStore() private var workoutSession: HKWorkoutSession! private var workoutBuilder: HKLiveWorkoutBuilder! override init() { super.init() requestAuthorization() startWorkoutSession() } private func requestAuthorization() { let heartRateType = HKQuantityType.quantityType(forIdentifier: .heartRate)! let respiratoryRateType = HKQuantityType.quantityType(forIdentifier: .respiratoryRate)! let HRVRateType = HKQuantityType.quantityType(forIdentifier: .heartRateVariabilitySDNN)! let temperatureRateType = HKQuantityType.quantityType(forIdentifier: .bodyTemperature)! let healthDataTypes: Set = [heartRateType, respiratoryRateType, HRVRateType, temperatureRateType] healthStore.requestAuthorization(toShare: healthDataTypes, read: healthDataTypes) { (success, error) in if !success { print("Authorization failed") } } } func workoutSession(_ workoutSession: HKWorkoutSession, didChangeTo toState: HKWorkoutSessionState, from fromState: HKWorkoutSessionState, date: Date) { } func workoutSession(_ workoutSession: HKWorkoutSession, didFailWithError error: any Error) { } func workoutBuilderDidCollectEvent(_ workoutBuilder: HKLiveWorkoutBuilder) { } func startWorkoutSession() { let configuration = HKWorkoutConfiguration() configuration.activityType = .other configuration.locationType = .indoor do { workoutSession = try HKWorkoutSession(healthStore: healthStore, configuration: configuration) workoutBuilder = workoutSession.associatedWorkoutBuilder() workoutBuilder.delegate = self workoutBuilder.dataSource = HKLiveWorkoutDataSource(healthStore: healthStore, workoutConfiguration: configuration) let dataSource = HKLiveWorkoutDataSource(healthStore: healthStore, workoutConfiguration: configuration) let respiratoryRate = HKQuantityType(.respiratoryRate) dataSource.enableCollection(for: respiratoryRate, predicate: nil) let bodyTemp = HKQuantityType(.bodyTemperature) dataSource.enableCollection(for: bodyTemp, predicate: nil) let hrv = HKQuantityType(.heartRateVariabilitySDNN) dataSource.enableCollection(for: hrv, predicate: nil) workoutSession.delegate = self workoutSession.startActivity(with: Date()) workoutBuilder.beginCollection(withStart: Date(), completion: { (success, error) in if let error = error { print("Error starting collection: \(error.localizedDescription)") } }) } catch { print("Failed to start workout session: \(error.localizedDescription)") } } func workoutBuilder(_ workoutBuilder: HKLiveWorkoutBuilder, didCollectDataOf collectedTypes: Set<HKSampleType>) { print("collected types: \(collectedTypes)") for type in collectedTypes { if let quantityType = type as? HKQuantityType { if quantityType == HKQuantityType.quantityType(forIdentifier: .heartRate) { if let heartRateQuantity = workoutBuilder.statistics(for: quantityType)?.mostRecentQuantity() { let heartRateUnit = HKUnit(from: "count/min") let heartRateValue = heartRateQuantity.doubleValue(for: heartRateUnit) print("heart rate: \(heartRateValue)") } } if quantityType == HKQuantityType.quantityType(forIdentifier: .heartRateVariabilitySDNN) { if let hrvQuantity = workoutBuilder.statistics(for: quantityType)?.mostRecentQuantity() { let hrvUnit = HKUnit.secondUnit(with: .milli) let hrvValue = hrvQuantity.doubleValue(for: hrvUnit) print("HRV: \(hrvValue)") } } if quantityType == HKQuantityType.quantityType(forIdentifier: .bodyTemperature) { if let bodyTempQuantity = workoutBuilder.statistics(for: quantityType)?.mostRecentQuantity() { let tempUnit = HKUnit.degreeCelsius() let tempValue = bodyTempQuantity.doubleValue(for: tempUnit) print("body temp: \(tempValue)") } } if quantityType == HKQuantityType.quantityType(forIdentifier: .respiratoryRate) { if let respRateQuantity = workoutBuilder.statistics(for: quantityType)?.mostRecentQuantity() { let respRateUnit = HKUnit(from: "count/min") let respRateValue = respRateQuantity.doubleValue(for: respRateUnit) print("breathing: \(respRateValue)") } } } } } }
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993
Sep ’24
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); } };
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146
Jul ’25
HealthKit permission sheet appears every time for some users - bug?
The HealthKit permission sheet is showing up every time the app opens for a few users of my app. It doesn't matter what action they take in the sheet. I have had them try toggling the permissions from the HealthKit system settings but that did not happen to fix the problem. Has anyone experienced this problem or know a fix? Its affecting a few users of my app. I haven't been able to find what in my code could be doing this, I suspect its a bug on HealthKit's side for specific users. I can't find anyone reporting this problem elsewhere so I have to assume its my fault, but the docs clearly state that the permission sheet will only be presented once.
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9
2k
Oct ’24
Overlapping Segments and Duplicate Start Times in Workout Data
Hello, We're encountering overlapping segments and discrepancies when analyzing running/workout data for a 5-mile run. The expected splits for the run are: 8:39 9:06 8:30 8:39 8:43 0:08 However, the raw data includes segments where start times begin before the previous segment ends, and there are duplicate start times. Below is a sample of the raw data: "startDate": "2024-09-09T19:32:00.308-0400", "eventType": "segment", "eventTypeInt": 7, "endDate": "2024-09-09T19:37:56.135-0400" }, { "startDate": "2024-09-09T19:32:00.308-0400", "eventType": "segment", "eventTypeInt": 7, "endDate": "2024-09-09T19:41:08.476-0400" },``` // Here's an example of where the second segment start time falls in side the first segments startDate and endDate "startDate": "2024-09-09T19:54:22.658-0400", "eventType": "segment", "eventTypeInt": 7, "endDate": "2024-09-09T19:59:41.215-0400" }, { "startDate": "2024-09-09T19:58:44.624-0400", "eventType": "segment", "eventTypeInt": 7, "endDate": "2024-09-09T20:07:23.216-0400"
8
0
879
Sep ’24