WWDC26 · 12 min · SwiftUI & UI Frameworks / Health & Fitness

Deliver workout insights with HealthKit workout zones

HealthKit makes it easier to provide workout insights — like heart rate and cycling power zones — in your app. Learn to leverage the built-in, personalized zones or create custom ones. Discover how to use the current zone and time spent in each zone to provide meaningful guidance during and after workouts.

Watch at developer.apple.com ↗

Transcript all transcripts

Chapters

0:01 — Introduction
2:17 — Accessing workout zones
6:19 — Live zone updates
8:11 — Preferred zones
9:00 — Custom zones

Code shown on screen · 7 snippets

Reading Heart Rate Zones from a completed workout swift · at 3:54 ↗

// Read heart rate zones from the completed workout

if let heartRateZoneGroup = workout.zoneGroupsByType?[HKQuantityType(.heartRate)] {
let zones = ZoneDisplayData(
    zoneCount: heartRateZoneGroup.configuration.zones.count,
    currentZoneIndex: nil,
    durations: heartRateZoneGroup.zoneDurations.map(\.duration)
)

Handling Live Zone Updates swift · at 7:57 ↗

func workoutBuilder(_ workoutBuilder: HKLiveWorkoutBuilder,
                    didUpdateWorkoutZone zoneUpdate: HKLiveWorkoutZoneUpdate) {
    guard let zoneGroup = zoneUpdate.zoneGroup else {
        return
    }
    if let currentIndex = zoneUpdate.currentZoneDuration?.zone.index {
        let data = ZoneDisplayData(
            zoneCount: zoneGroup.configuration.zones.count,
            currentZoneIndex: currentIndex,
            durations: zoneGroup.zoneDurations.map(\.duration)
        )
        Task { @MainActor in
            self.heartRateZones = data
        }
    }
}

Check if Preferred Zone has been set swift · at 9:19 ↗

if try await builder.zoneConfiguration(for: HKQuantityType(.heartRate)) == nil {

Create Zone Boundaries swift · at 9:24 ↗

let defaultHeartRateZoneThresholds = [91.0, 114.0, 136.0, 158.0]
    let bpmUnit = HKUnit.count().unitDivided(by: HKUnit.minute())
    let boundaries = defaultHeartRateZoneThresholds.map(
        {HKQuantity(unit: bpmUnit, doubleValue:$0)}
    )

Create Default Workout Zone Configuration swift · at 9:33 ↗

let heartRate = HKQuantityType(.heartRate)
    let defaultConfiguration = try HKWorkoutZoneConfiguration(quantityType: heartRate,
                                                              zoneBoundaries: boundaries)

Set Custom Zone Configuration swift · at 9:58 ↗

try await builder.setCustomZoneConfiguration(defaultConfiguration,
                                                 for: heartRate)
}

Begin Data Collection swift · at 10:03 ↗

// Begin data collection
let startDate = Date()
try await builder.beginCollection(at: startDate)

Resources

Sample code Tracking heart rate zones for workouts
Documentation Accessing workout zone data