HealthKit

PrismHealthKit provides a Sendable, actor-based wrapper around Apple’s HealthKit framework. Query health samples, compute statistics, and write data without managing HKHealthStore or HKSampleQuery directly.

Permissions

Request authorization for specific data types:

Request Health Permissions

import PrismCapabilities

let health = PrismHealthKit()

try await health.requestAuthorization(
    read: [.stepCount, .heartRate, .sleepAnalysis],
    write: [.bodyMass]
)

Supported Data Types

Type	Unit	Description
`.stepCount`	count	Daily step count
`.heartRate`	BPM	Heart rate measurements
`.activeEnergy`	kcal	Active calories burned
`.sleepAnalysis`	—	Sleep stage analysis
`.bodyMass`	kg	Body weight
`.height`	m	Body height
`.bloodOxygen`	%	Blood oxygen saturation
`.respiratoryRate`	breaths/min	Respiratory rate

Querying Samples

Fetch individual health samples within a date range:

Query Heart Rate

let samples = try await health.querySamples(
    type: .heartRate,
    start: Calendar.current.date(byAdding: .hour, value: -24, to: .now)!,
    end: .now
)

for sample in samples {
    print("\(sample.value) \(sample.unit)")  // "72.0 BPM"
    print("From \(sample.startDate) to \(sample.endDate)")
}

PrismHealthSample

public struct PrismHealthSample: Sendable {
    public let type: PrismHealthDataType
    public let value: Double
    public let unit: String
    public let startDate: Date
    public let endDate: Date
}

Statistics

Get aggregated statistics (sum, average, min, max) over a period:

Daily Step Statistics

let stats = try await health.queryStatistics(
    type: .stepCount,
    start: Calendar.current.startOfDay(for: .now),
    end: .now
)

print("Steps today: \(stats.sum ?? 0)")
print("Unit: \(stats.unit)")  // "count"

PrismHealthStatistics

public struct PrismHealthStatistics: Sendable {
    public let type: PrismHealthDataType
    public let sum: Double?
    public let average: Double?
    public let min: Double?
    public let max: Double?
    public let unit: String
}

Writing Data

Save health samples to HealthKit:

Save Body Mass

try await health.saveSample(
    type: .bodyMass,
    value: 75.5,
    unit: "kg",
    date: .now
)

Writing to HealthKit requires explicit write authorization for each data type. Always request write permissions before attempting to save.

Observing Changes

Stream real-time updates when new samples are added:

Observe Heart Rate

for await sample in health.observe(type: .heartRate) {
    print("New reading: \(sample.value) \(sample.unit)")
}

HealthKit data is privacy-sensitive. Your app must include the NSHealthShareUsageDescription and NSHealthUpdateUsageDescription keys in Info.plist.

Getting Started

Foundation

Network

Architecture

UI

Intelligence

Gamification

Security

Storage

Capabilities

Video

HealthKit

HealthKit

Permissions

Supported Data Types

Querying Samples

PrismHealthSample

Statistics

PrismHealthStatistics

Writing Data

Observing Changes

​HealthKit

​Permissions

​Supported Data Types

​Querying Samples

​PrismHealthSample

​Statistics

​PrismHealthStatistics

​Writing Data

​Observing Changes

HealthKit

Permissions

Supported Data Types

Querying Samples

PrismHealthSample

Statistics

PrismHealthStatistics

Writing Data

Observing Changes