Every question the Health Data pages answer
The 29 health data pages answer 132 named questions between them. Every one is listed below, and every link lands on the paragraph that answers it rather than the top of the page.
Heart Rate API: How to Get Heart-Rate Data Into Your App
- Is heart rate from a wearable measured or estimated?Heart rate itself is measured, not modeled. Most consumer devices read it optically with a PPG sensor (green or infrared LEDs at the wrist…
- How do I get real-time heart rate into an app?For live, in-workout HR, read on-device through a HealthKit workout session on iOS or Android Health Connect, or connect directly to a…
- Which data types expose heart rate on HealthKit and Health Connect?On Apple HealthKit, general samples come from `HKQuantityTypeIdentifierHeartRate`, with `HKQuantityTypeIdentifierRestingHeartRate`,…
- Can I get all-day and resting heart rate from Strava?No. Strava exposes heart rate only as a per-workout activity stream in BPM, not resting or continuous all-day HR. For resting HR and…
- Should I use an aggregator or integrate each wearable directly?Integrate directly when you support one or two sources or need on-device, low-latency reads; that keeps the data path simple. Use an…
HRV API: How to Get Heart Rate Variability Data
- Is HRV measured or estimated?The HRV value itself is measured from real beat-to-beat interval timing. What is not a direct measurement is the interpretation: RMSSD…
- What is the difference between RMSSD and SDNN in HRV APIs?They are two different statistics computed from the same interbeat intervals and are not directly comparable. The HRV Apple Watch records…
- Can I get HRV from a phone without a wearable?No. HRV needs a device that captures beat-to-beat intervals, so it requires a wearable (ring, watch, band) or a chest strap. A phone alone…
- Why do Oura and WHOOP HRV values differ from a morning app reading?Most consumer platforms compute HRV over a nocturnal/overnight window for comparability, while some apps use a guided morning spot reading.…
- Which API is best for HRV?For recovery or readiness scoring out of the box, Oura or WHOOP, which bake nightly HRV into their models. For a raw RMSSD trend on…
VO2 Max API: How to Get VO2 Max Data
- Is VO2 max from a watch accurate?Consumer VO2 max is an estimate, not a lab measurement, so treat it as a fitness-trend signal rather than a precise value. Accuracy varies…
- Which APIs expose VO2 max data?Apple HealthKit exposes HKQuantityTypeIdentifierVO2Max on-device, Android Health Connect exposes Vo2MaxRecord, and cloud wearable APIs…
- Is consumer VO2 max measured or estimated?Estimated on every consumer device. True VO2 max comes from a lab graded-exercise test with a metabolic cart. Watches and rings model it…
- Can I compare VO2 max across Garmin, Fitbit, and Apple?Not directly. Vendors label it differently (VO2 max, Cardio Fitness Score, Cardio Fitness) and use different estimation models, so the same…
- How do I read VO2 max in an iOS or Android app?On iOS, request permission and read HKQuantityTypeIdentifierVO2Max from HealthKit on-device; there is no Apple cloud pull. On Android, read…
Blood Oxygen (SpO2) API: How to Get SpO2 Data
- Is consumer SpO2 data a medical measurement?No. SpO2 is genuinely measured by an optical sensor, but consumer wearables and rings are marketed as general fitness and wellness devices…
- Which platform data types expose blood oxygen?On iOS, Apple HealthKit exposes HKQuantityTypeIdentifierOxygenSaturation as an on-device permissioned read. On Android, Health Connect…
- Can I get an Apple Watch blood oxygen reading in the US?It depends and is unsettled. Apple Watch's Blood Oxygen feature was disabled on new US units after a 2023 ITC order, then restored around…
- Do wearables give continuous SpO2 or just overnight readings?Both modes exist, but they differ by source. On-demand spot readings require the user to initiate and hold still; overnight or background…
- What is the easiest way to read SpO2 across many devices?Use an aggregator such as Terra, Junction, or Rook, which normalize SpO2 across providers behind one schema and webhooks where the…
Sleep Tracking API: How to Get Sleep Data Into Your App
- Are sleep stages from a wearable accurate?Sleep stages (light, deep, REM, awake) are estimated from movement, heart rate, HRV, and respiration, not from EEG, so they are modeled…
- Can I get sleep data from a phone without a wearable?Typically not reliably. Phones alone usually do not produce trustworthy staged sleep, so phone-only sleep should be treated as coarse.…
- Why do sleep stages differ between Oura, WHOOP, and Apple?Vendors use different stage taxonomies. Apple uses Core, Deep, REM, and Awake; others use Light, Deep, REM; WHOOP uses Light, REM, and…
- How do I access sleep data on iOS and Android?On iOS, read HealthKit's HKCategoryTypeIdentifierSleepAnalysis on-device with the user's permission. On Android, read Health Connect's…
- Can sleep tracking APIs diagnose sleep disorders?No. Consumer sleep data is a general wellness signal, not a medical diagnostic. Stages are estimates validated only imperfectly against…
Step Counting API: How to Get Step Data
- Can a phone count steps without a wearable?Yes. Step counting is one of the few fitness metrics fully available from a phone alone - its accelerometer feeds a pedometer. On iOS you…
- Why do my step counts look doubled?Because a phone and a paired watch both log steps, so naively summing every source roughly doubles the total. Use the platform's…
- Are step counts measured or estimated?They are counted, but algorithmically - motion-sensor pattern recognition interpreting accelerometer data, not a sensor that registers each…
- Did Health Connect change how steps are attributed in 2026?There is a reported 2026 change to on-device step attribution in Health Connect - legacy readings attributed to the "android" package…
- Which source should I use for step data?For the widest reach with least friction, read the on-device platform store (HealthKit on iOS, Health Connect on Android) so you inherit…
Workout Detection API: Get Recorded Workout Sessions
- Which providers auto-detect workouts vs. require a manual start?Fitbit SmartTrack auto-recognizes select activities after sustained movement and logs them with no manual start, while Apple Watch…
- How do I read workout sessions on iOS and Android?On iOS, read Apple HealthKit's HKWorkout on-device with per-type permission; each session carries an activity type plus fields like…
- Is a detected workout type accurate?The session's duration is measured, but the activity type and session boundaries are algorithmically inferred, especially for auto-detected…
- Is this the same as AI camera-based rep counting?No. This page covers recorded workout sessions from HealthKit, Health Connect, Strava, and Garmin. AI camera-based rep or exercise…
- How do I merge workouts from different sources?Activity-type taxonomies differ across HealthKit, Health Connect, Strava, and Garmin, so their type enums are not a 1:1 mapping. If you…
GPS Activity API: How to Get Route Data from Workouts
- Is GPS route data measured or estimated?The coordinates are measured by the device's GNSS/GPS receiver, not modeled. But the measurement is noisy: it drifts near buildings or tree…
- Can I get GPS route data from a phone without a wearable?Yes. A phone has GPS, so it can record a route on its own, and a GPS-capable watch or bike computer can too. A non-GPS wearable relies on…
- What are Strava's API restrictions for route data?Strava enforces rate limits and has been tightening access; for example the Explore Segments endpoint is documented as moving to an…
- Which API is best for GPS route data?To show a user their own route, the on-device path is least restrictive: HKWorkoutRoute on iOS, ExerciseRoute on Android. To pull routes…
- How do HealthKit and Health Connect expose route data?On iOS, HealthKit stores a route as HKWorkoutRoute attached to a workout; you read it with HKWorkoutRouteQuery and build it with…
Calorie Tracking API: How to Get Calorie Data
- Are calories burned measured or estimated?Estimated. Calories burned is a model derived from heart rate, motion, activity type, and your profile (age, weight, sex) via a proprietary…
- How do I get calories consumed from a fitness API?You do not get intake from a wearable or phone sensor, because nothing measures what a person eats. Calories consumed comes from food…
- What is the difference between active and total calories?Active energy is exercise/movement calories only; total energy includes basal (resting) energy on top. On HealthKit, activeEnergyBurned and…
- Why do calorie counts differ between my devices?Because they are estimates, not measurements. Each vendor uses a different proprietary model over heart rate, motion, and user profile, so…
- Which API is best for calorie tracking?For calories burned with the widest coverage, read the on-device platform energy types (active plus basal on HealthKit, active plus total…
Body Composition API: Weight, Body Fat, and Lean Mass Data
- Can a fitness watch or band measure body fat?No. A typical wrist wearable does not measure body fat, lean mass, or BMI. Those come from a smart scale using bioelectrical impedance, a…
- Is body fat percentage from a smart scale accurate?It is an estimate, not a lab measurement. Consumer scales use bioelectrical impedance analysis (BIA), which infers fat versus fat-free mass…
- How do I get weight and body fat data from HealthKit and Health Connect?Apple HealthKit exposes bodyMass, bodyFatPercentage, bodyMassIndex, and leanBodyMass as on-device quantity types you read with per-type…
- Is BMI measured or calculated?BMI is calculated, not measured. It is weight divided by height squared, so it is only as good as the weight and height behind it.…
- Which API is best for body composition?For a full breakdown of fat, muscle, water, and bone, integrate a smart-scale source; Withings is the common pick for a rich bioimpedance…
Menstrual Cycle API: How to Get Cycle Tracking Data
- Which Health Connect records cover menstrual cycle tracking?Health Connect groups them under Cycle Tracking: MenstruationFlowRecord (instantaneous, with a flow field taking FLOW_LIGHT, FLOW_MEDIUM,…
- Does Apple HealthKit predict ovulation, or only store what was logged?HealthKit stores samples; the prediction lives in Apple's Cycle Tracking feature, not in a type you read. Apple documents that Cycle…
- Can a wearable detect a period automatically, or must the user log it?Flow, spotting, cervical mucus quality, ovulation test results, and sexual activity are all logged by the person or written by another app;…
- What extra privacy obligations come with period-tracking data?Treat it as the most exposed category in consumer health. Google's Health Connect guidance is to request only the permissions and data…
- Which wearable cloud APIs return menstrual cycle data?Fewer than you would expect. Among the sources documented on our pages, Terra is the one that normalizes cycle data, with a menstruation…
Blood Glucose API: How to Get Glucose Data Into Your App
- Where does blood glucose data in HealthKit and Health Connect come from?Almost never from a fitness wearable. It comes from a fingerstick meter or a continuous glucose monitor, hardware sold and regulated as a…
- What units do blood glucose samples use, and how do I avoid a unit mix-up?Apple documents that blood glucose samples may be measured in mg/dL (milligrams per deciliter) or mmol/L (millimoles per liter) depending…
- Can I read continuous glucose monitor data through a fitness API?Usually indirectly. On a phone you read whatever the CGM's companion app wrote into HealthKit or Health Connect. Server-side, our pages…
- Is a glucose reading measured or estimated?Measured, not modeled - but glucose names several different measurements that are not interchangeable. Health Connect makes this explicit…
- What must a wellness app avoid claiming about glucose readings?Do not compute or display dosing suggestions, do not frame alerts as clinical instructions, and do not describe your app as monitoring or…
Blood Pressure API: How to Read BP Data In Your App
- Which platform data types store a blood pressure reading?Apple HealthKit uses two quantity sample types, HKQuantityTypeIdentifier.bloodPressureSystolic and…
- Why does HealthKit want systolic and diastolic combined into a correlation?Because on iOS the two halves are separate sample types, and only the correlation ties them together as one reading. Apple documents…
- Does Health Connect require body position and cuff site for BP?Yes. BloodPressureRecord lists systolic, diastolic, bodyPosition, measurementLocation, metadata, and time as mandatory fields. The…
- Can a smartwatch send blood pressure into my app without a cuff?Our pages document no consumer wrist wearable that measures blood pressure, so this is a claim to verify with the vendor rather than…
- Why do Health Connect blood pressure writes throw an exception?The record validates ranges and throws IllegalArgumentException when a value falls outside them. Health Connect documents systolic as valid…
Respiratory Rate API: How to Get Breathing-Rate Data
- What unit does respiratory rate use on HealthKit versus Health Connect?Health Connect fixes it: RespiratoryRateRecord exposes rate as a Double documented as respiratory rate in breaths per minute, with a valid…
- Does the API tell me how a breathing-rate value was produced?No. Neither platform type carries a method or source field. Health Connect's record holds only rate, time, and metadata, and Apple's is a…
- Can Health Connect compute a nightly average respiratory rate?Not for you. The Health Connect data types page lists aggregate metrics for several vitals, such as systolic and diastolic averages for…
- Which wearable APIs return a breathing rate field?On our pages, Oura API v2 returns respiratory rate as part of its sleep payload alongside sleep stages and HRV, and Fitbit's documented…
- Does an Apple Watch record breathing rate on its own?Apple's documentation for the respiratory rate quantity type states that the system automatically records samples on Apple Watch. Your app…
State of Mind API: How to Read and Write Mood Data in HealthKit
- What fields does an HKStateOfMind sample carry?Apple's initializer takes a date, a kind, a valence as a Double, an array of labels, an array of associations, and optional metadata. The…
- What numeric range does HealthKit use for mood valence?Apple's reference does not say. The valence property is declared as a Double and the initializer takes a Double, but the pages fetched on…
- Is a Health Connect mindfulness session the same as a mood log?No. Google's data types page defines MindfulnessSessionRecord as an interval record with a mindfulnessSessionType such as meditation,…
- Can mood samples my app saves to HealthKit show up in other apps?Yes, under the user's permissions. Apple's authorization guide notes that in iOS 17.2 and later the Journal app encourages reflection on…
Medications API: Reading Medication and Dose Logs From HealthKit
- What does HKMedicationDoseEvent.LogStatus record?It records what happened to a dose, in six cases Apple documents. taken and skipped are what the person logged. snoozed means they snoozed…
- How does Apple authorize access to Health app medications?Apple's reference says little. HKUserAnnotatedMedicationType is documented as representing the set of authorizeable…
- Can an app write medication doses into HealthKit?Apple's reference lists no initializer for HKMedicationDoseEvent, and HKUserAnnotatedMedication shows only init(coder:). The June 2025…
- Does Health Connect have a medication logging data type?Not for dose logging. Google's data types page lists no medication or dose record among the health and fitness types. Medication data…
Mental Health Assessments API: PHQ-9 and GAD-7 in HealthKit
- What answer values do HKPHQ9Assessment and HKGAD7Assessment accept?Both answer enums share four cases: notAtAll, severalDays, moreThanHalfTheDays and nearlyEveryDay. HKPHQ9Assessment.Answer adds a fifth,…
- What risk levels does HealthKit attach to PHQ-9 and GAD-7 samples?HKPHQ9Assessment.Risk has five cases: noneToMinimal, mild, moderate, moderatelySevere and severe. HKGAD7Assessment.Risk has four:…
- Can I compute my own PHQ-9 score instead of reading HealthKit's?You can, but then two numbers exist for one questionnaire. HKScoredAssessment exposes score as an Int, and Apple does not document how…
- Is there a Health Connect record for depression or anxiety screening?Google's data types page, fetched 2026-10-04, lists no questionnaire, assessment or screening record. Its Wellness category contains only…
Clinical Records API: Reading FHIR Health Records in HealthKit
- Which clinical record types can a HealthKit app request?Apple's HKClinicalTypeIdentifier lists nine: allergyRecord, conditionRecord, immunizationRecord, labResultRecord, medicationRecord,…
- Which FHIR versions does HealthKit return for health records?HKFHIRVersion, available from iOS 14.0, offers primaryDSTU2() and primaryR4(), and HKFHIRRelease has the cases dstu2, r4 and unknown. Each…
- Why do HealthKit clinical record dates not match the visit date?Apple documents that HKClinicalRecord inherits startDate and endDate from HKSample but does not fill them from the FHIR data. They reflect…
- Do I need permission to read SMART Health Cards in HealthKit?Not in the usual way. Apple documents that HKVerifiableClinicalRecordQueryDescriptor does not need prior authorization, because HealthKit…
Health Connect Medical Records API: FHIR Data on Android
- Which FHIR versions and resource types does Health Connect accept?Google's data format page lists R4 (v4.0.1) and R4B (v4.3.0). The validation table accepts fourteen resource types: AllergyIntolerance,…
- How do read and write permissions differ for Health Connect medical data?Writing is one permission for everything: Google describes PERMISSION_WRITE_MEDICAL_DATA as allowing the write of medical data of any type,…
- Can a background Health Connect app read medical records written by other apps?Only with an extra permission. Google's HealthConnectClient reference says a caller holding only a medical read permission can, in the…
- What happens if one resource in an upsertMedicalResources batch is invalid?The whole batch fails. Google documents that if any request fails to be processed for any reason, none of the requests are inserted or…
Resting Heart Rate API: How to Read RHR From HealthKit and Health Connect
- Why do resting heart rate samples disappear from HealthKit during the day?Because Apple documents that behaviour. The restingHeartRate discussion states that resting heart rate estimates become more accurate as…
- What is the difference between a resting heart rate sample and a sedentary heart rate sample in HealthKit?Apple draws the line explicitly. A sedentary sample is an ordinary heartRate sample whose HKMetadataKeyHeartRateMotionContext metadata is…
- Does Health Connect compute resting heart rate from HeartRateRecord data?Nothing in Google's documentation says it does. The RestingHeartRateRecord reference describes the class as capturing the user's resting…
- What unit and type does RestingHeartRateRecord use for the value?The Kotlin reference types beatsPerMinute as a Long, documented as heart beats per minute, a required field with a validation range of 1 to…
- Which wearable cloud APIs give me a daily resting heart rate?On our pages, WHOOP's read:recovery scope grants recovery data that includes HRV and resting heart rate, and Fitbit's heart rate time…
Body Temperature API: Core, Skin and Wrist Temperature Data
- Is Health Connect skin temperature an absolute reading or a change?A change. Google documents SkinTemperatureRecord as a Series record that can represent a series of measurements of temperature differences.…
- Does Wear OS Health Services have a temperature data type?No. None of the 65 DataType constants in Google's Health Services reference, read on 2026-10-04, is a temperature, so a Wear OS app cannot…
- How does a Bluetooth thermometer say whether a reading is Celsius or Fahrenheit?With bit 0 of the Flags field that opens the Temperature Measurement characteristic, 0x2A1C. When the bit is 0 the measurement value is in…
- What does the Google Health API report for nightly skin temperature?One Daily record per night from daily-sleep-temperature-derivations. Google describes nightlyTemperatureCelsius as the mean of skin…
ECG API: Electrocardiogram and Irregular Rhythm Data
- Can an app read raw ECG waveforms from the Google Health API?Yes. The electrocardiogram data type carries waveformSamples, an array of lead I voltage values starting at the beginning of the reading,…
- Does Health Connect have an ECG or irregular rhythm record?No. None of the 42 record classes on Google's Health Connect data-types page, read on 2026-10-03, is an ECG or rhythm record, and none of…
- What does HealthKit's atrial fibrillation burden measure?Apple describes atrialFibrillationBurden as an estimate of the percentage of time a person's heart shows signs of atrial fibrillation while…
- Why are all Google Health API alert windows marked positive?Because Google says so in the AlertWindow schema: the current version of the algorithm only produces an alert if all windows are positive,…
- Which time zone is a Google Health API ECG reading in?Possibly none. Google notes that historical ECG data lacks time zone offsets, so the start and end offsets will be missing or zero and the…
Distance Tracking API: Walking, Running and Activity Distance by Platform
- Why does HealthKit have nine distance types?Because Apple makes the activity part of the type. HealthKit has distanceWalkingRunning and distanceCycling from iOS 8.0, distanceSwimming…
- What unit does the Google Health API use for distance?Millimeters, as an integer. Google's distance type has a required millimeters field, typed string/int64 in the discovery document and…
- Is there a maximum distance per Health Connect DistanceRecord?Yes. Google documents the distance field's valid range as 0 to 1,000,000 meters, and suggests writing several distance records for a long…
- Where does Wear OS Health Services get its distance from?Google does not fix it. Its description of the DataType class says a data type defines only the representation and format of the data, not…
Floors Climbed and Elevation API: Floors, Elevation Gain and Altitude
- Can I list floors data points from the Google Health API?No. Google's data-types table lists only reconcile, rollup and dailyRollup for the floors type, so there is no list operation to page…
- Does HealthKit have an elevation gain data type?No sample type. HealthKit records elevation as workout metadata: HKMetadataKeyElevationAscended and HKMetadataKeyElevationDescended hold…
- Can elevation gained be negative?On two platforms the documented range allows it. Health Connect's ElevationGainedRecord accepts -1,000,000 to 1,000,000 meters, and the…
- Why is Wear OS floors climbed a Double?Google's Health Services reference says partial floors are supported, so FLOORS is represented as a Double: the number of floors climbed…
Active Minutes API: Activity Intensity, Exercise Time and Sedentary Time
- Does Health Connect record light-intensity activity minutes?No. ActivityIntensityRecord has two intensity constants, ACTIVITY_INTENSITY_TYPE_MODERATE and ACTIVITY_INTENSITY_TYPE_VIGOROUS, and…
- How are Active Zone Minutes weighted in the Google Health API?Google's field description says an Active Zone Minute equals 1 for the low-intensity fat-burn zone and 2 for the high-intensity cardio and…
- Is HealthKit exercise time the same thing as active minutes?Not by definition. Apple describes appleExerciseTime as measuring the amount of time the user spent exercising, a cumulative value in time…
- Which API reports sedentary time?Of the platforms this site covers, only the Google Health API reports it as data. Its sedentary-period type records periods when the user…
Heart Rate Zones API: Zone Thresholds and Time in Zone
- How does the Google Health API define its heart rate zones?Google describes daily-heart-rate-zones as the user's heart rate zone thresholds based on the Karvonen algorithm for a specific day. Each…
- Do HealthKit or Health Connect store heart rate zones?No. Neither Apple's HealthKit identifiers nor Health Connect's record classes, nor Wear OS Health Services' data types, include a heart…
- What is the difference between time in heart rate zone and Active Zone Minutes?Time in heart rate zone is a plain duration: intervals tagged LIGHT, MODERATE, VIGOROUS or PEAK, rolled up into the time spent in each.…
- How do Bluetooth devices store heart rate zone limits?As User Data service characteristics that hold the boundaries between zones in beats per minute, each limit a single uint8. Three Zone…
Cycling Power API: Power, Cadence and Speed Data Across Platforms
- Which Health Connect permission covers cycling cadence?The exercise permission. Google's data-types table puts CyclingPedalingCadenceRecord under android.permission.health.READ_EXERCISE and…
- Does the Bluetooth CSC characteristic send cadence in RPM?No. CSC Measurement (0x2A5B) sends a cumulative crank revolution count as a uint16 and the time of the last crank event in units of 1/1024…
- Why does Apple describe HealthKit cycling power as estimated?That is Apple's wording: cyclingPower measures the estimated power being used while riding a bike, and cyclingFunctionalThresholdPower the…
- Can I get cycling power from the Google Health API?Not from a data type. None of the Google Health API's 44 data types is power or cadence, and the exercise summary in its discovery document…
Running Metrics API: Speed, Power, Stride Length and Running Form Data
- Does Health Connect have records for running stride length or ground contact time?No. Google's Health Connect reference, read on 2026-10-03, has no stride length, vertical oscillation or ground contact time record. It has…
- What unit is Wear OS pace in?Milliseconds per kilometer. Google's Health Services reference describes PACE as pace at a specific point in time that will be 0 if the…
- Is vertical oscillation measured the same way on Apple Watch and Wear OS?Not by the platforms' own definitions. Apple describes runningVerticalOscillation as pelvis vertical range of motion during a single…
- Which iOS version added HealthKit running power and stride length?iOS 16.0, with watchOS 9.0. Apple's availability data gives the same versions for all five running types: runningSpeed, runningPower,…
Swimming Data API: Strokes, Laps and Swim Distance by Platform
- Does Health Connect have a swimming stroke count record?No. Health Connect's record types, read from Google's reference on 2026-10-03, include no stroke count, lap count or swim distance record.…
- Which swim stroke types does the Google Health API record?Four named strokes plus unspecified. Each swim-lengths-data point has a swimStrokeType of FREESTYLE, BACKSTROKE, BREASTSTROKE, BUTTERFLY or…
- Where does HealthKit keep swim stroke style and pool length?In workout metadata keys rather than sample types. HKMetadataKeySwimmingStrokeStyle holds the predominant stroke style for a lap, set on…
- Is a swimming lap the same as a pool length in these APIs?None of the descriptions this site reads says. Google's swim-lengths-data counts strokes in the lap, while its exercise summary counts full…
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