diff --git a/src/app/__tests__/dashboard-hrv-rmssd-fallback.test.tsx b/src/app/__tests__/dashboard-hrv-rmssd-fallback.test.tsx
index 2c8790363..c063d13c1 100644
--- a/src/app/__tests__/dashboard-hrv-rmssd-fallback.test.tsx
+++ b/src/app/__tests__/dashboard-hrv-rmssd-fallback.test.tsx
@@ -24,9 +24,9 @@ import type { DataSummary } from "@/lib/analytics/trends";
  * The dashboard HRV tile must accept either HRV type.
  *
  * HRV is stored under two measurement types that are not the same measure:
- * SDNN (`HEART_RATE_VARIABILITY`, Apple / Fitbit / Google Health) and nightly
- * RMSSD (`HRV_RMSSD`, Oura / Polar / WHOOP, and a bridge pushing a Garmin-style
- * feed). Every other HRV surface already unions them — `/insights/hrv` via
+ * SDNN (`HEART_RATE_VARIABILITY`, Apple Health / Health Connect) and nightly
+ * RMSSD (`HRV_RMSSD`, Oura / Polar / WHOOP / Fitbit / Google Health, and a
+ * bridge pushing a Garmin-style feed). Every other HRV surface already unions them — `/insights/hrv` via
  * `fallbackMeasurementType`, the Coach via `COACH_SOURCE_MEASUREMENT_TYPES.hrv`,
  * the MCP reads via `withHrvFallback` — and `sub-page-metric.ts` states that
  * listing both is what keeps "the tab, pill, and dashboard tile lit whichever
@@ -141,16 +141,16 @@ describe("pickHrvSummary", () => {
 });
 
 describe("the RMSSD fallback cannot leak recovery-module data", () => {
-  it("drops HRV_RMSSD from the snapshot summaries when recovery is off", () => {
+  it("lists HRV_RMSSD among the recovery-off summary types", () => {
     // The half of this fix that is easy to miss. `HRV_RMSSD` is recovery-owned
     // in `METRIC_STATUS_MODULE_OWNERS`, which governs the metric-status and
     // MCP reads — but the dashboard snapshot gates off `SUMMARY_TYPE_MODULE`,
     // a DIFFERENT map, and that one did not list it. Inert while the tile read
-    // SDNN alone; the moment the tile falls back to RMSSD it would show a
-    // recovery-off account a tile built from recovery-owned rows.
+    // SDNN alone. The one exception, the tile's fallback for an account with
+    // no SDNN, is made in `gateSummariesByModules` (tested below).
     expect(disabledSummaryTypes({ recovery: false })).toContain("HRV_RMSSD");
     // SDNN is a plain vital and stays ungated — turning recovery off must not
-    // take the ordinary HRV tile away from an Apple / Fitbit account.
+    // take the ordinary HRV tile away from an Apple Health account.
     expect(disabledSummaryTypes({ recovery: false })).not.toContain(
       "HEART_RATE_VARIABILITY",
     );
@@ -290,35 +290,74 @@ describe("the gate reaches every feed, not just the default one", () => {
     expect(on.summaries.HRV_RMSSD).toBeDefined();
     expect(summaries.HRV_RMSSD).toBeDefined();
   });
+
+  it("keeps the RMSSD fallback for an account with no SDNN", () => {
+    // A Fitbit or Google Health account files its nightly HRV as RMSSD since
+    // migration 0420. On this tile RMSSD stands in for SDNN, a plain vital
+    // that paints with Recovery off, so the fallback must not vanish for the
+    // estimator the device reports.
+    const summaries = {
+      HEART_RATE_VARIABILITY: summary(0, 0),
+      HRV_RMSSD: summary(30, 42),
+    };
+    const lastSeen = {
+      HRV_RMSSD: { lastSeenAt: "2026-09-02T00:00:00.000Z" },
+    };
+    const off = gateSummariesByModules(summaries, lastSeen, {
+      recovery: false,
+    });
+    expect(off.summaries.HRV_RMSSD).toBeDefined();
+    expect(off.lastSeenByType.HRV_RMSSD).toBeDefined();
+    expect(pickHrvSummary(off.summaries).type).toBe("HRV_RMSSD");
+    // Another recovery-owned series is still stripped.
+    const withResting = gateSummariesByModules(
+      { ...summaries, RESTING_HEART_RATE: summary(5, 58) },
+      lastSeen,
+      { recovery: false },
+    );
+    expect(
+      (withResting.summaries as Record<string, unknown>).RESTING_HEART_RATE,
+    ).toBeUndefined();
+  });
 });
 
 describe("a switch that cannot do anything is not offered", () => {
-  // The symptom one step on from the original bug: with recovery off, a
-  // ring / strap account's only HRV series is withheld, so the tile can
-  // never paint — and before this, the toggle was still offered, still
-  // turned on, and still explained nothing. Same experience as the defect
-  // this change exists to remove, so it does not get to survive here.
-  it("drops the HRV toggle for a ring account with recovery off", () => {
+  it("drops the HRV toggle for an account with recovery off and no HRV", () => {
     expect(
-      unavailableWidgetIds({ recovery: false }, { hasSdnn: false }),
+      unavailableWidgetIds(
+        { recovery: false },
+        { hasSdnn: false, hasRmssd: false },
+      ),
     ).toEqual(["hrv"]);
   });
 
-  it("keeps the toggle for an account that has SDNN", () => {
-    // SDNN is a plain vital that no module owns, so the tile still works
-    // with recovery off. Taking this row away would be a new bug.
+  it("keeps the toggle for an account that has either estimator", () => {
     expect(
-      unavailableWidgetIds({ recovery: false }, { hasSdnn: true }),
+      unavailableWidgetIds(
+        { recovery: false },
+        { hasSdnn: true, hasRmssd: false },
+      ),
+    ).toEqual([]);
+    expect(
+      unavailableWidgetIds(
+        { recovery: false },
+        { hasSdnn: false, hasRmssd: true },
+      ),
     ).toEqual([]);
   });
 
   it("keeps the toggle whenever recovery is on", () => {
     expect(
-      unavailableWidgetIds({ recovery: true }, { hasSdnn: false }),
+      unavailableWidgetIds(
+        { recovery: true },
+        { hasSdnn: false, hasRmssd: false },
+      ),
     ).toEqual([]);
     // Fail-open on an unresolved map, like the module gate beside it: only
     // an explicit `false` takes a row away.
-    expect(unavailableWidgetIds({}, { hasSdnn: false })).toEqual([]);
+    expect(
+      unavailableWidgetIds({}, { hasSdnn: false, hasRmssd: false }),
+    ).toEqual([]);
   });
 });
 
diff --git a/src/app/api/dashboard/widgets/route.ts b/src/app/api/dashboard/widgets/route.ts
index 470c6362a..3c394cebf 100644
--- a/src/app/api/dashboard/widgets/route.ts
+++ b/src/app/api/dashboard/widgets/route.ts
@@ -235,7 +235,7 @@ export const GET = apiHandler(async () => {
   // linger for minutes after Recovery went off, which is the confusion this
   // is removing.
   //
-  // The SDNN probe is an index-only existence check
+  // The HRV probes are index-only existence checks
   // (`@@index([userId, type, measuredAt])`), not a summaries read; it runs
   // only when Recovery is off, so the common account pays nothing.
   // One flag, read the way this codebase reads one flag — not the whole
@@ -243,20 +243,22 @@ export const GET = apiHandler(async () => {
   // is the only module that decides it.
   const recoveryEnabled = await isModuleEnabled(user.id, "recovery");
   let hasSdnn = true;
+  let hasRmssd = true;
   if (!recoveryEnabled) {
-    const sdnnRow = await prisma.measurement.findFirst({
-      where: {
-        userId: user.id,
-        type: "HEART_RATE_VARIABILITY",
-        deletedAt: null,
-      },
-      select: { id: true },
-    });
+    const [sdnnRow, rmssdRow] = await Promise.all(
+      (["HEART_RATE_VARIABILITY", "HRV_RMSSD"] as const).map((type) =>
+        prisma.measurement.findFirst({
+          where: { userId: user.id, type, deletedAt: null },
+          select: { id: true },
+        }),
+      ),
+    );
     hasSdnn = sdnnRow !== null;
+    hasRmssd = rmssdRow !== null;
   }
   const unavailable = unavailableWidgetIds(
     { recovery: recoveryEnabled },
-    { hasSdnn },
+    { hasSdnn, hasRmssd },
   );
   return apiSuccess(
     unavailable.length > 0
diff --git a/src/app/insights/hrv/page.tsx b/src/app/insights/hrv/page.tsx
index f46fce113..06f3462a4 100644
--- a/src/app/insights/hrv/page.tsx
+++ b/src/app/insights/hrv/page.tsx
@@ -11,9 +11,9 @@ import { EcgCrossLink } from "@/components/insights/ecg-cross-link";
  * Heart-rate variability sub-page. Pairs with the iOS HKQuantityType
  * `heartRateVariabilitySDNN` ingest path; the user typically logs one
  * sample per night during sleep, so the chart is sparse but the
- * weekly trend is the load-bearing signal. Apple Health / Fitbit store
- * SDNN as millisecond `HEART_RATE_VARIABILITY` rows; Oura / Polar / WHOOP
- * store nightly RMSSD as `HRV_RMSSD`. The page renders SDNN when present
+ * weekly trend is the load-bearing signal. Apple Health and Health Connect
+ * store SDNN as millisecond `HEART_RATE_VARIABILITY` rows; Oura / Polar /
+ * WHOOP / Fitbit / Google Health store nightly RMSSD as `HRV_RMSSD`. The page renders SDNN when present
  * and falls back to the RMSSD series (labelled "RMSSD") otherwise, so a
  * ring / strap user's stored HRV always surfaces. Since iOS 27 an Apple
  * Watch writes both (#1110); with rows of both the page charts each on its
diff --git a/src/app/page-client.tsx b/src/app/page-client.tsx
index b72534282..02c00fe5d 100644
--- a/src/app/page-client.tsx
+++ b/src/app/page-client.tsx
@@ -491,8 +491,9 @@ export default function DashboardPageClient({
   // measurement-type enum), so no backend change was needed; the strip
   // tiles below self-gate on `count > 0`.
   // HRV is stored under two types and the tile has to accept either: SDNN
-  // (`HEART_RATE_VARIABILITY`, Apple / Fitbit / Google Health) or nightly
-  // RMSSD (`HRV_RMSSD`, Oura / Polar / WHOOP and bridge pushes). Reading
+  // (`HEART_RATE_VARIABILITY`, Apple Health / Health Connect) or nightly
+  // RMSSD (`HRV_RMSSD`, Oura / Polar / WHOOP / Fitbit / Google Health and
+  // bridge pushes). Reading
   // SDNN alone left a ring / strap account with a Settings toggle that
   // rendered nothing while `/insights/hrv` charted the same data. The
   // helper keeps the union in one place and hands back which type won, so
diff --git a/src/components/dashboard/dashboard-gates.ts b/src/components/dashboard/dashboard-gates.ts
index d219ffa9a..c26154b33 100644
--- a/src/components/dashboard/dashboard-gates.ts
+++ b/src/components/dashboard/dashboard-gates.ts
@@ -164,9 +164,9 @@ export const HRV_LABEL_KEY: Record<HrvSummaryType, string> = {
  * Which HRV series backs the dashboard tile.
  *
  * HRV is stored under two types and they are not the same measure: Apple
- * Health / Fitbit / Google Health write SDNN as `HEART_RATE_VARIABILITY`,
- * while Oura / Polar / WHOOP — and a Garmin-style feed pushed in through a
- * bridge — write nightly RMSSD as `HRV_RMSSD`. Every other HRV surface
+ * Health and Health Connect write SDNN as `HEART_RATE_VARIABILITY`, while
+ * Oura / Polar / WHOOP / Fitbit / Google Health — and a Garmin-style feed
+ * pushed in through a bridge — write nightly RMSSD as `HRV_RMSSD`. Every other HRV surface
  * already unions the two: `/insights/hrv` passes `fallbackMeasurementType`
  * (`app/insights/hrv/page.tsx`), the Coach resolves both
  * (`COACH_SOURCE_MEASUREMENT_TYPES.hrv`), and the MCP reads swap through
diff --git a/src/components/insights/healthkit-metric-page.tsx b/src/components/insights/healthkit-metric-page.tsx
index 0a595e3d9..22129a95e 100644
--- a/src/components/insights/healthkit-metric-page.tsx
+++ b/src/components/insights/healthkit-metric-page.tsx
@@ -59,9 +59,9 @@ export interface HealthKitMetricPageProps {
   /**
    * v1.17.0 — optional secondary MeasurementType the page falls back to
    * when the primary type has no rows but the fallback does. Used by HRV:
-   * the primary `HEART_RATE_VARIABILITY` (SDNN, Apple / Fitbit) is empty
-   * for a ring / strap user whose nightly HRV is stored as `HRV_RMSSD`
-   * (Oura / Polar / WHOOP). When the swap is active the chart, stat strip,
+   * the primary `HEART_RATE_VARIABILITY` (SDNN, Apple Health / Health
+   * Connect) is empty for a ring / strap user whose nightly HRV is stored as
+   * `HRV_RMSSD` (Oura / Polar / WHOOP / Fitbit / Google Health). When the swap is active the chart, stat strip,
    * "all values" list, and diversity nudge key off the fallback type and
    * `fallbackMeasureLabel` names the measure so the two are never silently
    * merged. Omit it and every other page renders byte-identically.
diff --git a/src/lib/ai/coach/source-measurement-types.ts b/src/lib/ai/coach/source-measurement-types.ts
index 186032b01..632a6f4ab 100644
--- a/src/lib/ai/coach/source-measurement-types.ts
+++ b/src/lib/ai/coach/source-measurement-types.ts
@@ -25,8 +25,9 @@ export const COACH_SOURCE_MEASUREMENT_TYPES: Readonly<
   pulse: ["PULSE"],
   mood: [],
   compliance: [],
-  // v1.30.4 (HRV union) — Oura / Polar / WHOOP write nightly HRV as RMSSD
-  // (`HRV_RMSSD`), never SDNN (`HEART_RATE_VARIABILITY`, Apple / Fitbit).
+  // v1.30.4 (HRV union) — Oura / Polar / WHOOP / Fitbit / Google Health
+  // write nightly HRV as RMSSD (`HRV_RMSSD`), never SDNN
+  // (`HEART_RATE_VARIABILITY`, Apple Health).
   // The app's HRV surface already unions both (`sub-page-metric.ts`);
   // resolving SDNN alone here made a ring/strap-only user's Coach context
   // + the `get_metric_series`/rich-read MCP paths report a false
diff --git a/src/lib/daily/__tests__/briefing-today.test.ts b/src/lib/daily/__tests__/briefing-today.test.ts
index a3b877539..584525a45 100644
--- a/src/lib/daily/__tests__/briefing-today.test.ts
+++ b/src/lib/daily/__tests__/briefing-today.test.ts
@@ -159,6 +159,41 @@ describe("briefingForToday", () => {
     );
   });
 
+  it("keeps an HRV signal for an account whose only HRV is RMSSD", () => {
+    // Fitbit, Google Health and every ring file nightly HRV as `HRV_RMSSD`;
+    // the Coach reads the `hrv` source over both series, so a signal written
+    // for such an account is a reading of today when the RMSSD row is.
+    const hrvBriefing: DailyBriefing = {
+      ...BRIEFING,
+      signalsOfDay: [
+        {
+          sourceMetric: "hrv",
+          tone: "info",
+          headline: "HRV höher als üblich",
+          nudge: "Guter Tag für Bewegung.",
+          delta: "+6,4 ms vs. dein 30-Tage-Mittel",
+        },
+      ],
+    };
+    const out = briefingForToday(hrvBriefing, {
+      ...BERLIN,
+      generatedAt: "2026-10-05T04:00:00Z",
+      lastSeenAt: (type) =>
+        type === "HRV_RMSSD" ? "2026-10-05T04:30:00Z" : null,
+    });
+    expect(out?.signalsOfDay?.map((s) => s.delta)).toEqual([
+      "+6 ms vs. dein 30-Tage-Mittel",
+    ]);
+    // Neither series measured today: still dropped.
+    const stale = briefingForToday(hrvBriefing, {
+      ...BERLIN,
+      generatedAt: "2026-10-05T04:00:00Z",
+      lastSeenAt: (type) =>
+        type === "HRV_RMSSD" ? "2026-10-04T04:30:00Z" : null,
+    });
+    expect(stale?.signalsOfDay).toEqual([]);
+  });
+
   it("serves no briefing written on an earlier day, just after midnight", () => {
     // Written 23:30 on the 4th, read 00:10 on the 5th (Berlin).
     expect(
diff --git a/src/lib/daily/briefing-today-read.ts b/src/lib/daily/briefing-today-read.ts
index 49ace8d14..77e535585 100644
--- a/src/lib/daily/briefing-today-read.ts
+++ b/src/lib/daily/briefing-today-read.ts
@@ -16,6 +16,7 @@ import type { Locale } from "@/lib/i18n/config";
 import { readBriefingGeneratedAt } from "@/lib/insights/briefing-generated-at";
 import { userDayKey } from "@/lib/tz/format";
 import {
+  ALL_SIGNAL_READING_TYPES,
   SIGNAL_READING_TYPE,
   briefingForToday,
 } from "@/lib/daily/briefing-today";
@@ -47,7 +48,7 @@ export async function readSignalLastSeen(
     const rows = await readLatestEver(
       prisma,
       userId,
-      Object.values(SIGNAL_READING_TYPE) as MeasurementType[],
+      ALL_SIGNAL_READING_TYPES as MeasurementType[],
     );
     const byType = new Map(
       rows.map((row) => [
diff --git a/src/lib/daily/briefing-today-warm.ts b/src/lib/daily/briefing-today-warm.ts
index 885df5ecf..5d7f31244 100644
--- a/src/lib/daily/briefing-today-warm.ts
+++ b/src/lib/daily/briefing-today-warm.ts
@@ -25,7 +25,7 @@ import { checkRateLimit } from "@/lib/rate-limit";
 import { annotate } from "@/lib/logging/context";
 import type { Locale } from "@/lib/i18n/config";
 import { userDayKey } from "@/lib/tz/format";
-import { SIGNAL_READING_TYPE } from "@/lib/daily/briefing-today";
+import { ALL_SIGNAL_READING_TYPES } from "@/lib/daily/briefing-today";
 import { enqueueTodayBriefingWarm } from "@/lib/jobs/insight-pregenerate-shared";
 
 /** A claim outlives the longest local day (a 25 h DST day) with margin. */
@@ -63,7 +63,7 @@ export function todayWarmReasons(input: TodayWarmInput): string[] {
   ) {
     reasons.push("day");
   }
-  for (const type of new Set(Object.values(SIGNAL_READING_TYPE))) {
+  for (const type of ALL_SIGNAL_READING_TYPES) {
     const at = input.lastSeenAt(type);
     if (at === null) continue;
     const atMs = Date.parse(at);
diff --git a/src/lib/daily/briefing-today.ts b/src/lib/daily/briefing-today.ts
index 4ca2b7720..da8181518 100644
--- a/src/lib/daily/briefing-today.ts
+++ b/src/lib/daily/briefing-today.ts
@@ -46,6 +46,28 @@ export const SIGNAL_READING_TYPE: Readonly<Record<string, string>> = {
   glucose: "BLOOD_GLUCOSE",
 };
 
+/**
+ * Every type a signal's reading may be filed under. HRV is two series: SDNN
+ * (`HEART_RATE_VARIABILITY`, Apple Health / Health Connect) and nightly RMSSD
+ * (`HRV_RMSSD`, rings, straps, Fitbit and Google Health). The Coach reads the
+ * `hrv` source over both, so a signal written for an RMSSD-only account is a
+ * reading of today when either series has one; checking SDNN alone dropped
+ * every such signal. Both read in whole milliseconds, so the precision
+ * lookup keeps the one type in {@link SIGNAL_READING_TYPE}.
+ */
+export const SIGNAL_READING_TYPES: Readonly<Record<string, readonly string[]>> =
+  Object.fromEntries(
+    Object.entries(SIGNAL_READING_TYPE).map(([metric, type]) => [
+      metric,
+      metric === "hrv" ? [type, "HRV_RMSSD"] : [type],
+    ]),
+  );
+
+/** Every type any signal may be a reading of, once each. */
+export const ALL_SIGNAL_READING_TYPES: readonly string[] = [
+  ...new Set(Object.values(SIGNAL_READING_TYPES).flat()),
+];
+
 /** The locale's decimal and grouping separators ("," and "." for de). */
 function separators(locale: Locale): { decimal: string; group: string } {
   const parts = new Intl.NumberFormat(resolveIntlLocale(locale)).formatToParts(
@@ -204,8 +226,8 @@ export function briefingForToday(
   };
   const signalsOfDay = briefing.signalsOfDay
     .filter((signal) => {
-      const type = SIGNAL_READING_TYPE[signal.sourceMetric];
-      return type === undefined || measuredToday(type);
+      const types = SIGNAL_READING_TYPES[signal.sourceMetric];
+      return types === undefined || types.some(measuredToday);
     })
     .map((signal) =>
       signal.delta
diff --git a/src/lib/dashboard/snapshot.ts b/src/lib/dashboard/snapshot.ts
index 5008cffda..4293375c7 100644
--- a/src/lib/dashboard/snapshot.ts
+++ b/src/lib/dashboard/snapshot.ts
@@ -1153,6 +1153,7 @@ function gateLayoutByModules(
   const unavailable = new Set(
     unavailableWidgetIds(modules, {
       hasSdnn: (summaries.HEART_RATE_VARIABILITY?.count ?? 0) > 0,
+      hasRmssd: (summaries.HRV_RMSSD?.count ?? 0) > 0,
     }),
   );
   return hideModuleWidgets(layout, modules, unavailable);
diff --git a/src/lib/dashboard/widget-modules.ts b/src/lib/dashboard/widget-modules.ts
index a8b025d99..4142347e7 100644
--- a/src/lib/dashboard/widget-modules.ts
+++ b/src/lib/dashboard/widget-modules.ts
@@ -120,26 +120,30 @@ export function disabledSummaryTypes(
  *
  * `hrv` is that widget. The tile takes SDNN when the account has it and
  * falls back to nightly RMSSD otherwise (see `pickHrvSummary`). RMSSD is
- * recovery-owned, so with Recovery off it is stripped from every feed —
- * which leaves a ring / strap account, whose only HRV is RMSSD, holding a
- * switch that is on and a tile that can never paint, with nothing saying
- * why. That is precisely the defect the RMSSD fallback exists to remove, so
- * it must not survive one step further on. An account WITH SDNN keeps the
- * row: its tile still works with Recovery off, because SDNN is a plain
- * vital that no module owns.
+ * recovery-owned everywhere else, but on this tile it stands in for SDNN, a
+ * plain vital no module owns, so `gateSummariesByModules` keeps it with
+ * Recovery off for an account that has no SDNN. The toggle is dead only for
+ * an account with Recovery off and no HRV of either kind.
  *
  * Decided from server-resolved facts and handed to the client, so the
  * Settings screen does not have to fetch dashboard data to find out.
  */
 export function unavailableWidgetIds(
   modules: Partial<Record<ModuleKey, boolean>>,
-  facts: { hasSdnn: boolean },
+  facts: { hasSdnn: boolean; hasRmssd: boolean },
 ): string[] {
   const out: string[] = [];
-  if (modules.recovery === false && !facts.hasSdnn) out.push("hrv");
+  if (modules.recovery === false && !facts.hasSdnn && !facts.hasRmssd) {
+    out.push("hrv");
+  }
   return out;
 }
 
+function hasRows(summary: unknown): boolean {
+  const count = (summary as { count?: unknown } | undefined)?.count;
+  return typeof count === "number" && count > 0;
+}
+
 export function gateSummariesByModules<
   S extends Record<string, unknown>,
   L extends Record<string, unknown>,
@@ -149,6 +153,15 @@ export function gateSummariesByModules<
   modules: Partial<Record<ModuleKey, boolean>>,
 ): { summaries: S; lastSeenByType: L } {
   const dropped = disabledSummaryTypes(modules);
+  // The HRV tile's RMSSD fallback rides with SDNN, not with recovery. SDNN is
+  // a plain vital on this surface and paints with Recovery off; an account
+  // whose only HRV is RMSSD (a ring or strap, and every Fitbit or Google
+  // Health account since migration 0420 refiled their nightly HRV) would
+  // otherwise lose the tile for the estimator its device happens to report.
+  // Kept only while the account has no SDNN, so the series never mixes.
+  if (dropped.has("HRV_RMSSD") && !hasRows(summaries.HEART_RATE_VARIABILITY)) {
+    dropped.delete("HRV_RMSSD");
+  }
   if (dropped.size === 0) return { summaries, lastSeenByType };
   const outSummaries = {} as S;
   for (const [type, summary] of Object.entries(summaries)) {
diff --git a/src/lib/insights/derived/__tests__/readiness.test.ts b/src/lib/insights/derived/__tests__/readiness.test.ts
index 5371acb2f..62b83a5ee 100644
--- a/src/lib/insights/derived/__tests__/readiness.test.ts
+++ b/src/lib/insights/derived/__tests__/readiness.test.ts
@@ -133,6 +133,40 @@ describe("computeReadiness gating", () => {
     }
   });
 
+  it("renormalises over the other components for an account whose only HRV is RMSSD", async () => {
+    // Fitbit and Google Health file nightly HRV as `HRV_RMSSD` (migration
+    // 0420). Readiness stays on SDNN by design, so such an account has no
+    // HRV component: it must drop out with weight 0 and the rest carry the
+    // score, never an error and never an RMSSD value read as SDNN.
+    const days = (type: string, base: number) =>
+      Array.from({ length: 10 }, (_, i) => ({
+        value: base,
+        measuredAt: new Date(
+          `2026-05-${String(15 + i).padStart(2, "0")}T07:00:00Z`,
+        ),
+        type,
+      }));
+    measurementFindMany.mockImplementation(
+      async (args: { where: { type: unknown } }) => {
+        const type = args.where.type;
+        if (type === "RESTING_HEART_RATE") return days(type, 58);
+        if (type === "RESPIRATORY_RATE") return days(type, 14);
+        if (type === "HRV_RMSSD") return days(type, 42);
+        return [];
+      },
+    );
+    const result = await computeReadiness("u1", PROFILE, { now: NOW });
+    expect(result.status).toBe("ok");
+    if (result.status !== "ok") return;
+    const hrv = result.value.components.find((c) => c.key === "hrv");
+    expect(hrv).toMatchObject({ value: null, weight: 0 });
+    const present = result.value.components.filter((c) => c.value !== null);
+    expect(present.map((c) => c.key).sort()).toEqual(["respiratory", "rhr"]);
+    const total = present.reduce((sum, c) => sum + c.weight, 0);
+    expect(total).toBeCloseTo(1, 10);
+    expect(Number.isFinite(result.value.score)).toBe(true);
+  });
+
   it("reports confidence reflecting REAL history depth, not the constant window", async () => {
     // 10 distinct backing days on a 30-day window. Pre-fix `historyDays` was
     // pinned to `windowDays` so `historyFraction` was always 1 and confidence
diff --git a/src/lib/insights/metric-availability.ts b/src/lib/insights/metric-availability.ts
index e5ed659b1..2f761a6bd 100644
--- a/src/lib/insights/metric-availability.ts
+++ b/src/lib/insights/metric-availability.ts
@@ -62,9 +62,9 @@ export type InsightMetric =
   | "ACTIVE_ENERGY"
   // v1.4.32 — wave-A HealthKit metrics promoted to first-class sub-pages.
   | "HEART_RATE_VARIABILITY"
-  // v1.17.0 — RMSSD-flavoured HRV. Oura / Polar / WHOOP write nightly HRV
-  // as `HRV_RMSSD`; Apple Health / Fitbit write SDNN as
-  // `HEART_RATE_VARIABILITY`. The `hrv` sub-page gates on either so a
+  // v1.17.0 — RMSSD-flavoured HRV. Oura / Polar / WHOOP / Fitbit / Google
+  // Health write nightly HRV as `HRV_RMSSD`; Apple Health and Health Connect
+  // write SDNN as `HEART_RATE_VARIABILITY`. The `hrv` sub-page gates on either so a
   // ring / strap user's stored HRV lights the tab, pill, and dashboard.
   | "HRV_RMSSD"
   | "RESTING_HEART_RATE"
@@ -182,8 +182,8 @@ export function hasMetricData(
     return (inputs.summaries?.WEIGHT?.count ?? 0) > 0;
   }
   if (metric === "HEART_RATE_VARIABILITY") {
-    // v1.17.0 — surface SDNN (`HEART_RATE_VARIABILITY`, Apple / Fitbit)
-    // OR RMSSD (`HRV_RMSSD`, Oura / Polar / WHOOP). Either stream lights
+    // v1.17.0 — surface SDNN (`HEART_RATE_VARIABILITY`, Apple Health)
+    // OR RMSSD (`HRV_RMSSD`, Oura / Polar / WHOOP / Fitbit / Google Health). Either stream lights
     // the HRV tab, pill, and dashboard tile.
     return (
       (inputs.summaries?.HEART_RATE_VARIABILITY?.count ?? 0) > 0 ||
diff --git a/src/lib/insights/sub-page-metric.ts b/src/lib/insights/sub-page-metric.ts
index cb9eca51c..c088eabd5 100644
--- a/src/lib/insights/sub-page-metric.ts
+++ b/src/lib/insights/sub-page-metric.ts
@@ -120,7 +120,8 @@ const SUB_PAGE_METRIC = {
   // ── cardiovascular ──
   "resting-pulse": ["RESTING_HEART_RATE"],
   // v1.17.0 — HRV surfaces both flavours: SDNN (`HEART_RATE_VARIABILITY`,
-  // Apple / Fitbit) and RMSSD (`HRV_RMSSD`, Oura / Polar / WHOOP). A
+  // Apple Health) and RMSSD (`HRV_RMSSD`, Oura / Polar / WHOOP / Fitbit /
+  // Google Health). A
   // ring / strap user stores only RMSSD; listing both keeps the tab,
   // pill, and dashboard tile lit whichever source the user has.
   hrv: ["HEART_RATE_VARIABILITY", "HRV_RMSSD"],
diff --git a/src/lib/mcp/rich-reads.ts b/src/lib/mcp/rich-reads.ts
index aa2160b46..e32f4ba55 100644
--- a/src/lib/mcp/rich-reads.ts
+++ b/src/lib/mcp/rich-reads.ts
@@ -157,9 +157,9 @@ export interface RichMetric {
   /**
    * v1.30.4 (G4/HRV union) — a secondary `MeasurementType` to read instead of
    * `measurementType` when the user has ZERO rows of the primary type. HRV is
-   * the only metric that carries one today: Apple Health / Fitbit write SDNN
-   * (`HEART_RATE_VARIABILITY`); Oura / Polar / WHOOP write nightly RMSSD
-   * (`HRV_RMSSD`) only. Mirrors the app's HRV sub-page fallback
+   * the only metric that carries one today: Apple Health writes SDNN
+   * (`HEART_RATE_VARIABILITY`); Oura / Polar / WHOOP / Fitbit / Google Health
+   * write nightly RMSSD (`HRV_RMSSD`) only. Mirrors the app's HRV sub-page fallback
    * (`HealthKitMetricPage`'s `fallbackMeasurementType` prop) so a ring/strap
    * -only account resolves over MCP the same data it sees in the app instead
    * of a false `{ present: false }`.
diff --git a/src/lib/report-selection/__tests__/catalogue-guard.test.ts b/src/lib/report-selection/__tests__/catalogue-guard.test.ts
index 952114f1f..6b270286d 100644
--- a/src/lib/report-selection/__tests__/catalogue-guard.test.ts
+++ b/src/lib/report-selection/__tests__/catalogue-guard.test.ts
@@ -30,6 +30,8 @@ import {
   SHARE_GROUPS,
   STRUCTURED_LEAF_IDS,
   leafLabelKey,
+  LEAF_MODULE,
+  MEASUREMENT_LEAF_GROUP,
 } from "../catalogue";
 import { STANDARD_TEMPLATE_LEAVES, standardTemplateFor } from "../template";
 
@@ -192,3 +194,17 @@ describe("the standard-report action", () => {
     );
   });
 });
+
+describe("heart-rate variability in the report", () => {
+  // Fitbit and Google Health file nightly HRV as RMSSD (migration 0420), so
+  // for those accounts RMSSD is the only HRV the report can show. It is its
+  // own cardio leaf beside SDNN, never folded into it, and like SDNN no
+  // module gates it: a report with Recovery off must not lose the account's
+  // only HRV series for the estimator its device reports.
+  it("files SDNN and RMSSD as separate, ungated cardio leaves", () => {
+    for (const type of ["HEART_RATE_VARIABILITY", "HRV_RMSSD"] as const) {
+      expect(MEASUREMENT_LEAF_GROUP[type]).toBe("cardio");
+      expect(LEAF_MODULE[type]).toBeUndefined();
+    }
+  });
+});