Reading Data

You can query health data from Apple HealthKit and Android Health Connect using the IHealthService interface. Always request read permissions first.

Querying Health Data

public class HealthDashboardViewModel(IHealthService health)
{
    async Task LoadDataAsync()
    {
        // 1. Request permissions (read-only shorthand)
        var result = await health.RequestPermissions(
            DataType.StepCount,
            DataType.HeartRate,
            DataType.Calories,
            DataType.Distance
        );

        // Or request per-metric read/write permissions in a single call
        // await health.RequestPermissions(
        //     (PermissionType.Read, DataType.StepCount),
        //     (PermissionType.Read, DataType.HeartRate),
        //     (PermissionType.Write, DataType.Weight),
        //     (PermissionType.ReadWrite, DataType.BloodPressure)
        // );

        // 2. Check which permissions were granted
        foreach (var (type, success) in result)
        {
            if (!success)
                Console.WriteLine($"Permission denied for {type}");
        }

        // 3. Query data for the last 24 hours
        var end = DateTimeOffset.Now;
        var start = end.AddDays(-1);

        var steps = (await health.GetStepCounts(start, end, Interval.Days)).Sum(x => x.Value);
        var calories = (await health.GetCalories(start, end, Interval.Days)).Sum(x => x.Value);
        var distance = (await health.GetDistances(start, end, Interval.Days)).Sum(x => x.Value);
        var heartRate = (await health.GetAverageHeartRate(start, end, Interval.Days)).Average(x => x.Value);

        // 4. Blood pressure returns a special result type
        var bp = await health.GetBloodPressure(start, end, Interval.Days);
        if (bp.Any())
        {
            var avgSystolic = bp.Average(x => x.Systolic);
            var avgDiastolic = bp.Average(x => x.Diastolic);
        }

        // 5. Hourly breakdown
        var hourlySteps = await health.GetStepCounts(start, end, Interval.Hours);
        foreach (var bucket in hourlySteps)
        {
            Console.WriteLine($"{bucket.Start:g} - {bucket.End:g}: {bucket.Value:N0} steps");
        }
    }
}

Menstruation / Period Tracking

Menstruation flow is categorical and event-based, so it does not use Interval bucketing. Read the raw records over a date range with GetMenstruationFlow:

await health.RequestPermissions(DataType.MenstruationFlow);

var end = DateTimeOffset.Now;
var start = end.AddMonths(-1);

var records = await health.GetMenstruationFlow(start, end);
foreach (var r in records)
{
    // r.Flow is a MenstrualFlow enum: Unspecified, None, Light, Medium, Heavy
    Console.WriteLine($"{r.Start:d}: {r.Flow}{(r.IsCycleStart ? " (cycle start)" : "")}");
}

Note

The None flow level and the IsCycleStart flag are iOS-only. On Android (Health Connect), None is reported as Unspecified and IsCycleStart is always false.

More Numeric Metrics

Beyond the core activity/body/vitals metrics, the same interval-bucketed pattern works for blood glucose, body temperature, respiratory rate, VO2 max, heart rate variability, lean body mass, active/basal energy, floors climbed, wheelchair pushes, speed, and power:

await health.RequestPermissions(
    DataType.BloodGlucose,
    DataType.RespiratoryRate,
    DataType.Vo2Max,
    DataType.HeartRateVariability,
    DataType.ActiveEnergyBurned,
    DataType.FloorsClimbed
);

var end = DateTimeOffset.Now;
var start = end.AddDays(-1);

var glucose = (await health.GetBloodGlucose(start, end, Interval.Days)).Average(x => x.Value);        // mg/dL
var resp = (await health.GetRespiratoryRate(start, end, Interval.Days)).Average(x => x.Value);         // breaths/min
var vo2 = (await health.GetVo2Max(start, end, Interval.Days)).Average(x => x.Value);                   // mL/kg/min
var hrv = (await health.GetHeartRateVariability(start, end, Interval.Days)).Average(x => x.Value);     // ms
var active = (await health.GetActiveEnergyBurned(start, end, Interval.Days)).Sum(x => x.Value);        // kcal
var floors = (await health.GetFloorsClimbed(start, end, Interval.Days)).Sum(x => x.Value);            // count

Caution

Heart rate variability is reported as SDNN on iOS and RMSSD on Android — both in milliseconds but computed differently, so values are not directly comparable across platforms. Speed maps to walking speed and Power to cycling power on iOS.

Reproductive & Cycle Tracking

Sexual activity, ovulation tests, cervical mucus, and intermenstrual bleeding are event-based (like menstruation flow) — read the raw records over a date range, no Interval:

await health.RequestPermissions(
    DataType.SexualActivity,
    DataType.OvulationTest,
    DataType.CervicalMucus,
    DataType.IntermenstrualBleeding
);

var sexual = await health.GetSexualActivity(start, end);          // .Protection: Unspecified/Protected/Unprotected
var ovulation = await health.GetOvulationTests(start, end);       // .Outcome: Inconclusive/Positive/High/Negative
var mucus = await health.GetCervicalMucus(start, end);            // .Appearance: Dry/Sticky/Creamy/Watery/EggWhite
var spotting = await health.GetIntermenstrualBleeding(start, end);// event-only (no value)

Workouts

await health.RequestPermissions(DataType.Workout);

var workouts = await health.GetWorkouts(start, end);
foreach (var w in workouts)
{
    // w.Workout is a WorkoutType (Running, Cycling, Swimming, …)
    Console.WriteLine($"{w.Workout}: {w.TotalEnergyKilocalories} kcal, {w.TotalDistanceMeters} m");
}

Note

On Android (Health Connect), a workout’s TotalEnergyKilocalories and TotalDistanceMeters are null on read — Health Connect stores energy and distance as separate records from the exercise session.

Nutrition

await health.RequestPermissions(DataType.Nutrition);

var meals = await health.GetNutrition(start, end);
foreach (var m in meals)
    Console.WriteLine($"{m.Meal} {m.Name}: {m.EnergyKilocalories} kcal, {m.ProteinGrams}g protein");

Real-Time Observation

See the dedicated Observing Data page for streaming health data changes via IAsyncEnumerable<HealthResult>.

Best Practices

1. Always request permissions first — Call RequestPermissions before reading data
2. Use appropriate intervals — Interval.Days for summaries, Interval.Hours for detailed breakdowns
3. Handle empty results — Check .Any() before calling .Average() to avoid InvalidOperationException
4. Use CancellationToken — Pass cancellation tokens for long-running queries
5. Sum vs Average — Use .Sum() for cumulative metrics (steps, calories, distance, hydration, sleep) and .Average() for point-in-time metrics (heart rate, weight, height, body fat, O2 sat, resting HR)
6. Blood pressure is special — It returns BloodPressureResult (not NumericHealthResult) with separate Systolic and Diastolic values
7. Menstruation is special — It returns MenstruationFlowResult with a categorical MenstrualFlow value and is read via GetMenstruationFlow(start, end) (no Interval)