Health data

Each data point that a health measure reads from Google Health Connect or Apple Health becomes one measurement whose data is a HealthData object. All health data has the data type dk.cachet.carp.health, which is also its __type in JSON. The healthDataType field says what kind of data a point holds.

The measurement's sensorStartTime and sensorEndTime are the sample's dateFrom and dateTo in microseconds since 1970, not the time of the read. For the measurement envelope around the data, see Measurements and data.

Fields

HealthData has these fields:

HealthData does not keep the recording method, metadata or device model of the plugin's data point. The data therefore cannot tell manual entries from measured ones.

To use the values in the app, filter the measurement stream on the data class:

client.measurements
    .where((measurement) => measurement.data is HealthData)
    .listen((measurement) {
      final data = measurement.data as HealthData;
      final value = data.value;
      if (value is NumericHealthValue) {
        print('${data.healthDataType}: ${value.numericValue} ${data.unit}');
      } else if (value is WorkoutHealthValue) {
        print('Workout: ${value.workoutActivityType.name}');
      }
    });

Value classes

The class of value depends on the data type, and its __type in JSON is the class name. Most data types use NumericHealthValue:

Optional fields are left out of the JSON when they have no value. For the workout activity types, see Workout types.

Units

Each data type arrives in the default unit that the health plugin defines for it, and unit names that unit. Sleep, mindfulness and headache types hold the duration of the sample in minutes. For the unit of every type, see All data types.

Platform differences

The same data type can carry different details on the two platforms:

On iOS, GENDER and BLOOD_TYPE hold the raw value of HealthKit's biological sex and blood type. BIRTH_DATE holds the birth date in seconds since 1970.

Record IDs and duplicates

HealthData has a record ID that is not part of the JSON: uuid, healthDataType, dateFrom and dateTo, joined by |, for example 85328732-41d3-53b2-a81e-007f33bee353|STEPS|2026-01-26T07:00:00.000Z|2026-01-26T08:00:00.000Z. Health Connect gives all samples of one record the same uuid, so the record ID adds the data type and the time span.

The SQLite data manager stores each record ID once for each deployment and device role. It drops a data point that it has already stored, with some limits:

• Data points without a uuid have no record ID, so the SQLite data manager stores GENDER, BIRTH_DATE and BLOOD_TYPE again on every run.
• A background measure stores its data under the role name of the health service, by default Health Service. A health app task uses the role name of the phone, by default Smartphone. The same data point read by both is stored twice.
• The CARP Web Services (CAWS) data manager buffers data with the SQLite data manager and by default deletes it after upload. It therefore drops a copy only while the earlier copy waits for upload. The file and console data managers keep every copy.

For the data managers, see Data managers.

Example data

Each example shows the data object of one measurement:

{
  "__type": "dk.cachet.carp.health",
  "uuid": "85328732-41d3-53b2-a81e-007f33bee353",
  "value": {
    "__type": "NumericHealthValue",
    "numericValue": 1982
  },
  "unit": "COUNT",
  "healthDataType": "STEPS",
  "dateFrom": "2026-01-26T07:00:00.000Z",
  "dateTo": "2026-01-26T08:00:00.000Z",
  "platform": "GOOGLE_HEALTH_CONNECT",
  "deviceId": "unknown",
  "sourceId": "",
  "sourceName": "com.sec.android.app.shealth"
}

{
  "__type": "dk.cachet.carp.health",
  "uuid": "236C6441-BE81-4231-8CB2-25F9483B4967",
  "value": {
    "__type": "NumericHealthValue",
    "numericValue": 17.770999999999997
  },
  "unit": "KILOCALORIE",
  "healthDataType": "BASAL_ENERGY_BURNED",
  "dateFrom": "2026-01-26T12:39:46.373Z",
  "dateTo": "2026-01-26T12:54:23.152Z",
  "platform": "APPLE_HEALTH",
  "deviceId": "unknown",
  "sourceId": "com.apple.health.4B76DB4C-F19C-4D05-8766-FC7EC4DEF393",
  "sourceName": "Apple Watch"
}

{
  "__type": "dk.cachet.carp.health",
  "uuid": "5f0c2a9e-7d41-4b8e-9a26-3c1e8b7d4f60",
  "value": {
    "__type": "NumericHealthValue",
    "numericValue": 452
  },
  "unit": "MINUTE",
  "healthDataType": "SLEEP_SESSION",
  "dateFrom": "2026-01-25T22:41:00.000Z",
  "dateTo": "2026-01-26T06:13:00.000Z",
  "platform": "GOOGLE_HEALTH_CONNECT",
  "deviceId": "unknown",
  "sourceId": "",
  "sourceName": "com.google.android.apps.fitness"
}

{
  "__type": "dk.cachet.carp.health",
  "uuid": "c3a8e1d2-4f6b-4a9c-8e7d-1b2f3a4c5d6e",
  "value": {
    "__type": "WorkoutHealthValue",
    "workoutActivityType": "RUNNING",
    "totalEnergyBurned": 312,
    "totalEnergyBurnedUnit": "KILOCALORIE",
    "totalDistance": 5012,
    "totalDistanceUnit": "METER",
    "totalSteps": 5640,
    "totalStepsUnit": "COUNT"
  },
  "unit": "NO_UNIT",
  "healthDataType": "WORKOUT",
  "dateFrom": "2026-01-26T06:30:00.000Z",
  "dateTo": "2026-01-26T07:02:00.000Z",
  "platform": "GOOGLE_HEALTH_CONNECT",
  "deviceId": "unknown",
  "sourceId": "",
  "sourceName": "com.google.android.apps.fitness"
}

For the data types and their platforms, see Data types.