diff --git a/src/components/insights/__tests__/workout-list.test.tsx b/src/components/insights/__tests__/workout-list.test.tsx
index 337fc58b2..d6cb72ec5 100644
--- a/src/components/insights/__tests__/workout-list.test.tsx
+++ b/src/components/insights/__tests__/workout-list.test.tsx
@@ -47,15 +47,27 @@ describe("<WorkoutList>", () => {
     expect(html).toContain("320 kcal");
   });
 
+  it("renders aggregate average HR without claiming an HR series", () => {
+    const html = render(
+      <WorkoutList workouts={[{ ...ROW, hasHrSeries: false }]} />,
+    );
+
+    expect(html).toContain('data-slot="workout-list-avg-hr"');
+    expect(html).toContain("145 bpm");
+    expect(html).not.toContain('data-slot="workout-list-glyph-hr"');
+  });
+
   it("omits the chip when the field is null", () => {
     const noDistance: WorkoutListEntry = {
       ...ROW,
       distanceM: null,
       activeEnergyKcal: null,
+      avgHr: null,
     };
     const html = render(<WorkoutList workouts={[noDistance]} />);
     expect(html).not.toContain('data-slot="workout-list-distance"');
     expect(html).not.toContain('data-slot="workout-list-energy"');
+    expect(html).not.toContain('data-slot="workout-list-avg-hr"');
   });
 
   it("falls back to the canonical sport string for unknown sport types", () => {
diff --git a/src/lib/workouts/__tests__/hr-series.test.ts b/src/lib/workouts/__tests__/hr-series.test.ts
index 98e43e060..0beab9c57 100644
--- a/src/lib/workouts/__tests__/hr-series.test.ts
+++ b/src/lib/workouts/__tests__/hr-series.test.ts
@@ -121,6 +121,31 @@ describe("buildWorkoutHrSeries", () => {
     expect(result).toBeNull();
   });
 
+  it("does not synthesize a curve from aggregate HR or zone durations", async () => {
+    findMany.mockResolvedValue([]);
+    const result = await buildWorkoutHrSeries({
+      ...base,
+      storedSamples: null,
+      // Aggregate-only WHOOP fields deliberately are not inputs to the
+      // curve builder. Keep them on this structural fixture to pin that a
+      // future widening cannot silently fabricate time-series points.
+      avgHeartRate: 145,
+      maxHeartRate: 180,
+      metadata: {
+        zoneDurations: {
+          zone_two_milli: 300_000,
+          zone_three_milli: 300_000,
+        },
+      },
+    } as Parameters<typeof buildWorkoutHrSeries>[0] & {
+      avgHeartRate: number;
+      maxHeartRate: number;
+      metadata: unknown;
+    });
+
+    expect(result).toBeNull();
+  });
+
   it("hides when bucket coverage is below 40 %", async () => {
     // 10 samples all clustered in the first minute of a 10-minute run →
     // enough raw samples, but coverage is ~1 bucket of ~75.