diff --git a/Strand/App/AppModel.swift b/Strand/App/AppModel.swift
index 5f39d18033..42f4536953 100644
--- a/Strand/App/AppModel.swift
+++ b/Strand/App/AppModel.swift
@@ -1467,10 +1467,10 @@ final class AppModel: ObservableObject {
     /// HR-zone haptic coaching: buzz when crossing into the top zone (ease off) or back to recovery.
     private func coachZone(_ hr: Int?) {
         guard behavior.zoneCoaching, live.bonded, live.worn, let hr, hr >= 30 else { return }
-        let maxHR = Double(profile.hrMax)
-        guard maxHR > 0 else { return }
-        let pct = Double(hr) / maxHR
-        let zone = pct >= 0.9 ? 5 : pct >= 0.8 ? 4 : pct >= 0.7 ? 3 : pct >= 0.6 ? 2 : 1
+        guard profile.hrMax > 0 else { return }
+        // #531: route the haptic coach through the profile's effective zone set (personalized when set,
+        // conventional %HRmax otherwise) instead of hardcoded percentage bands.
+        let zone = profile.hrZoneSet.zoneNumber(forBPM: Double(hr))
         defer { lastCoachZone = zone }
         guard lastCoachZone != -1, zone != lastCoachZone else { return }
         if zone == 5, lastCoachZone < 5 { buzz(loops: 3) }          // entered max , ease off
diff --git a/Strand/Data/Repository.swift b/Strand/Data/Repository.swift
index aa9433d951..db1f7ab0ed 100644
--- a/Strand/Data/Repository.swift
+++ b/Strand/Data/Repository.swift
@@ -2729,13 +2729,12 @@ final class Repository: ObservableObject {
     /// day-level union, so a bout detected on a second WHOOP had its zones computed from a strap that
     /// never recorded it. `source` defaults to "" (⇒ the imported branch, the union) so a caller
     /// without a row keeps today's behaviour.
-    func workoutZoneMinutes(from: Int, to: Int, age: Int, source: String = "") async -> [Double]? {
+    func workoutZoneMinutes(from: Int, to: Int, zoneSet: HRZoneSet, source: String = "") async -> [Double]? {
         guard to > from else { return nil }
         let ids = Self.workoutHrDeviceIds(source: source, activeStrapId: deviceId,
                                           importedIds: importedReadIds)
         let samples = await hrSamples(deviceIds: ids, from: from, to: to)
         guard !samples.isEmpty else { return nil }
-        let zoneSet = HRZones.zones(age: age > 0 ? Double(age) : 30)
         let tiz = HRZones.timeInZone(samples, zoneSet: zoneSet)
         let minutes = tiz.seconds.map { $0 / 60.0 }
         return minutes.contains(where: { $0 > 0 }) ? minutes : nil
diff --git a/Strand/Screens/LiveView.swift b/Strand/Screens/LiveView.swift
index ed1d239a4c..65d63e34cc 100644
--- a/Strand/Screens/LiveView.swift
+++ b/Strand/Screens/LiveView.swift
@@ -757,7 +757,7 @@ private struct LiveHeartReadout: View {
     /// The live HR zone for the focal readout's colour world (presentation only). 0 = below Zone 1.
     private var liveZone: Int {
         guard let bpm = displayHR else { return 0 }
-        return HRZones.zones(maxHR: Double(hrMax)).zoneNumber(forBPM: Double(bpm))
+        return model.profile.hrZoneSet.zoneNumber(forBPM: Double(bpm))
     }
 
     /// The focal vessel / numeral colour: the live HR-zone hue when streaming, the Effort world otherwise.
diff --git a/Strand/Screens/LiveWorkoutView.swift b/Strand/Screens/LiveWorkoutView.swift
index 10ab5fc274..cb035c0357 100644
--- a/Strand/Screens/LiveWorkoutView.swift
+++ b/Strand/Screens/LiveWorkoutView.swift
@@ -38,7 +38,7 @@ struct LiveWorkoutView: View {
     /// control must not end the workout instantly with no way back.
     @State private var showEndConfirm = false
 
-    private var zoneSet: HRZoneSet { HRZones.zones(maxHR: Double(model.profile.hrMax)) }
+    private var zoneSet: HRZoneSet { model.profile.hrZoneSet }
     private var zone: Int { model.bpm.map { zoneSet.zoneNumber(forBPM: Double($0)) } ?? 0 }
 
     var body: some View {
diff --git a/Strand/Screens/WorkoutDetailView.swift b/Strand/Screens/WorkoutDetailView.swift
index 4acdb2501f..cf6b4c75d9 100644
--- a/Strand/Screens/WorkoutDetailView.swift
+++ b/Strand/Screens/WorkoutDetailView.swift
@@ -127,7 +127,7 @@ struct WorkoutDetailView: View {
             }
         }
         if minutes == nil {
-            minutes = await repo.workoutZoneMinutes(from: row.startTs, to: row.endTs, age: profile.age,
+            minutes = await repo.workoutZoneMinutes(from: row.startTs, to: row.endTs, zoneSet: profile.hrZoneSet,
                                                     source: row.source)
         }
 
diff --git a/android/app/src/main/java/com/noop/analytics/HrZones.kt b/android/app/src/main/java/com/noop/analytics/HrZones.kt
index 4c6c21fcac..0d6316d251 100644
--- a/android/app/src/main/java/com/noop/analytics/HrZones.kt
+++ b/android/app/src/main/java/com/noop/analytics/HrZones.kt
@@ -230,11 +230,18 @@ object HrZones {
  */
 internal class HrZoneSetCache {
     private var maxHR = Double.NaN
+    private var custom: List<Double>? = null
     private var set: HrZoneSet? = null
 
-    /** The `manual`-source zone set for [maxHR], rebuilt only when [maxHR] differs from the last call. */
-    fun zones(maxHR: Double): HrZoneSet {
-        set?.let { if (maxHR == this.maxHR) return it }
-        return HrZones.zones(maxHR = maxHR).also { this.maxHR = maxHR; set = it }
+    /**
+     * The effective zone set for [maxHR] and optional [customLowerBounds], rebuilt only when an input
+     * differs from the last call — so the 1 Hz coach path reuses it, and personalized zones (#531) are
+     * honoured instead of the maxHR-only default.
+     */
+    fun zones(maxHR: Double, customLowerBounds: List<Double>? = null): HrZoneSet {
+        set?.let { if (maxHR == this.maxHR && customLowerBounds == custom) return it }
+        return HrZones.zones(maxHR = maxHR, customLowerBounds = customLowerBounds).also {
+            this.maxHR = maxHR; custom = customLowerBounds; set = it
+        }
     }
 }
diff --git a/android/app/src/main/java/com/noop/ui/AppViewModel.kt b/android/app/src/main/java/com/noop/ui/AppViewModel.kt
index b55786b95e..0b0a3095fc 100644
--- a/android/app/src/main/java/com/noop/ui/AppViewModel.kt
+++ b/android/app/src/main/java/com/noop/ui/AppViewModel.kt
@@ -1746,8 +1746,7 @@ class AppViewModel(app: Application) : AndroidViewModel(app) {
         val ids = WhoopRepository.workoutHrDeviceIds(source, rowDeviceId, deviceId)
         val samples = runCatching { repository.hrSamplesFor(ids, from, to) }.getOrDefault(emptyList())
         if (samples.isEmpty()) return null
-        val age = profileStore.age.toDouble().takeIf { it > 0 } ?: 30.0
-        val zoneSet = com.noop.analytics.HrZones.zones(age = age)
+        val zoneSet = profileStore.hrZoneSet
         val tiz = com.noop.analytics.HrZones.timeInZone(samples, zoneSet)
         val minutes = tiz.seconds.map { it / 60.0 }
         return if (minutes.any { it > 0.0 }) minutes else null
@@ -2609,9 +2608,11 @@ class AppViewModel(app: Application) : AndroidViewModel(app) {
         if (hr < 30) return
         val maxHR = profileStore.hrMax.toDouble()
         if (maxHR <= 0) return
-        // Memoized on maxHR: this runs every ~1 Hz live-HR sample while zone coaching is active, but the
-        // zone set only changes when the user edits their max HR — so don't rebuild it per tick.
-        val zone = zoneSetCache.zones(maxHR).zoneNumber(hr.toDouble())
+        // Memoized on maxHR + personalized bounds: this runs every ~1 Hz live-HR sample while zone
+        // coaching is active, but the zone set only changes when the user edits their max HR or custom
+        // zones — so don't rebuild it per tick.
+        val zone = zoneSetCache.zones(maxHR, profileStore.hrZoneThresholds?.map(Int::toDouble))
+            .zoneNumber(hr.toDouble())
         val previous = lastZone
         lastZone = zone
         val loops = zoneCoachBuzzLoops(previous, zone, _zoneCoachRecovery.value)
diff --git a/android/app/src/main/java/com/noop/ui/AutomationsScreen.kt b/android/app/src/main/java/com/noop/ui/AutomationsScreen.kt
index 0fca2ba37e..7df721ed99 100644
--- a/android/app/src/main/java/com/noop/ui/AutomationsScreen.kt
+++ b/android/app/src/main/java/com/noop/ui/AutomationsScreen.kt
@@ -86,7 +86,7 @@ fun AutomationsScreen(viewModel: AppViewModel) {
     val zoneCoachRecovery by viewModel.zoneCoachRecovery.collectAsStateWithLifecycle()
     // The Zone 5 entry threshold (≥ 90% of HR-max), from the same HrZones model used everywhere.
     val zone5Bpm = remember(profile.hrMax) {
-        HrZones.zones(maxHR = profile.hrMax.toDouble()).zones.firstOrNull { it.number == 5 }?.lower?.roundToInt() ?: 0
+        profile.hrZoneSet.zones.firstOrNull { it.number == 5 }?.lower?.roundToInt() ?: 0
     }
 
     // Inactivity reminder (#419) — real + persisted via InactivityPrefs (opt-in, default OFF). Seeded
diff --git a/android/app/src/main/java/com/noop/ui/LiveScreen.kt b/android/app/src/main/java/com/noop/ui/LiveScreen.kt
index 0ac5b74019..3bb9a72a7a 100644
--- a/android/app/src/main/java/com/noop/ui/LiveScreen.kt
+++ b/android/app/src/main/java/com/noop/ui/LiveScreen.kt
@@ -136,7 +136,7 @@ fun LiveScreen(viewModel: AppViewModel, onManageDevices: () -> Unit = {}) {
     // Live HR zone for the focal readout's colour world (presentation only — same shared HrZones model
     // the live-workout screen uses). 0 = below Zone 1 / no HR yet.
     val profile = remember { ProfileStore.from(context.applicationContext) }
-    val zoneSet = remember(profile.hrMax) { HrZones.zones(maxHR = profile.hrMax.toDouble()) }
+    val zoneSet = remember(profile.hrMax, profile.hrZoneThresholds) { profile.hrZoneSet }
     val liveZone = bpm?.let { zoneSet.zoneNumber(it.toDouble()) } ?: 0
 
     // HR-zone coaching state, shown read-only here; the toggles live in Automations.
diff --git a/android/app/src/main/java/com/noop/ui/LiveWorkoutScreen.kt b/android/app/src/main/java/com/noop/ui/LiveWorkoutScreen.kt
index 28b686d204..330564d583 100644
--- a/android/app/src/main/java/com/noop/ui/LiveWorkoutScreen.kt
+++ b/android/app/src/main/java/com/noop/ui/LiveWorkoutScreen.kt
@@ -96,7 +96,7 @@ fun LiveWorkoutScreen(vm: AppViewModel, onClose: () -> Unit) {
     LaunchedEffect(w == null) { if (w == null) onClose() }
     if (w == null) return
 
-    val zoneSet = remember(profile.hrMax) { HrZones.zones(maxHR = profile.hrMax.toDouble()) }
+    val zoneSet = remember(profile.hrMax, profile.hrZoneThresholds) { profile.hrZoneSet }
     val zone = bpm?.let { zoneSet.zoneNumber(it.toDouble()) } ?: 0
 
     // Guards the destructive End action behind a confirm (#517) — a stray tap on the full-width