diff --git a/src/components/charts/__tests__/health-chart-heading-level.test.tsx b/src/components/charts/__tests__/health-chart-heading-level.test.tsx
new file mode 100644
index 000000000..bcd67184d
--- /dev/null
+++ b/src/components/charts/__tests__/health-chart-heading-level.test.tsx
@@ -0,0 +1,79 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { renderToStaticMarkup } from "react-dom/server";
+import deMessages from "../../../../messages/de.json";
+
+/**
+ * Chart card heading level.
+ *
+ * The icon-less chart header (dashboard cells, /insights/bmi, the sleep
+ * overview) titles itself at the second level. It has to: the card is a
+ * sibling of the other cards around it, and those already name themselves
+ * there — the dashboard's "Recent unlocks" and "Recent workouts" tiles render
+ * `<TileHeader titleAs="h2">`, and the metric subpages' target / usual-range
+ * cards are `<h2>` too. At `<h3>` the card claimed to be nested inside a
+ * section that does not exist, and the page skipped a level straight from its
+ * `<h1>`: the dashboard read h1 → h3 → h3 → h3 → h2 → h2 and /insights/bmi
+ * read h1 → h3 → h2.
+ *
+ * The browser scan in `e2e/a11y.spec.ts` catches a regression here through
+ * axe's `heading-order` rule, but only in the e2e job. This is the cheap
+ * guard that fails in the unit run.
+ */
+
+function buildData(): unknown[] {
+  const out: Array<{ date: string; timestamp: number; PULSE: number }> = [];
+  const base = Date.UTC(2026, 0, 1, 12, 0, 0);
+  for (let i = 0; i < 10; i++) {
+    out.push({
+      date: `2026-01-${String(i + 1).padStart(2, "0")}`,
+      timestamp: base + i * 86_400_000,
+      PULSE: 60 + i,
+    });
+  }
+  return out;
+}
+
+vi.mock("@/hooks/use-auth", () => ({
+  useAuth: () => ({
+    isAuthenticated: true,
+    user: null,
+    isLoading: false,
+  }),
+}));
+
+describe("<HealthChart> — card heading level", () => {
+  beforeEach(() => {
+    vi.resetModules();
+  });
+
+  it("titles the icon-less chart card at the second level, never the third", async () => {
+    const data = buildData();
+
+    vi.doMock("@tanstack/react-query", () => ({
+      useQuery: () => ({ data, isLoading: false }),
+      useQueryClient: () => ({
+        cancelQueries: () => Promise.resolve(),
+        getQueryData: () => undefined,
+        setQueryData: () => undefined,
+        invalidateQueries: () => Promise.resolve(),
+      }),
+      useMutation: () => ({ mutate: () => undefined, isPending: false }),
+    }));
+
+    const { I18nProvider } = await import("@/lib/i18n/context");
+    const { HealthChart } = await import("../health-chart");
+
+    const html = renderToStaticMarkup(
+      <I18nProvider initialLocale="de" initialMessages={deMessages}>
+        <HealthChart types={["PULSE"]} title="Pulse" unit="bpm" />
+      </I18nProvider>,
+    );
+
+    // The title is a real heading carrying the real title text, not a styled
+    // div — assert both halves so a silent demotion to a `<span>` fails too.
+    expect(html).toContain('<h2 class="text-sm font-semibold">Pulse</h2>');
+    expect(html).not.toContain("<h3");
+
+    vi.doUnmock("@tanstack/react-query");
+  });
+});
diff --git a/src/components/charts/health-chart.tsx b/src/components/charts/health-chart.tsx
index ea6df35be..55938706b 100644
--- a/src/components/charts/health-chart.tsx
+++ b/src/components/charts/health-chart.tsx
@@ -246,7 +246,7 @@ interface HealthChartProps {
    * v1.12.8 — optional leading glyph for the chart card's `<TileHeader>`.
    * When supplied, the chart header renders the canonical icon + title row
    * (same size + spacing as every other Insights tile) instead of the bare
-   * `<h3>`. Omitted on the dashboard / mini mounts, which keep the compact
+   * `<h2>`. Omitted on the dashboard / mini mounts, which keep the compact
    * heading. Accepts any component that takes a `className` (the contract
    * `<TileHeader>` and the stat strip's `icon` already use), so a page can
    * thread the same glyph it hands the stat strip.
@@ -1691,11 +1691,23 @@ export function HealthChart({
                 `<TileHeader>` (icon + title at `text-base`, foreground
                 colour, h-5 w-5) so it matches the assessment / target /
                 stat tiles. The dashboard / ad-hoc mounts omit the icon and
-                keep the compact `<h3>`. */}
+                keep the compact heading.
+
+                That compact heading is an `<h2>`, not an `<h3>`. The card is
+                a sibling of the other cards in the same grid, and those name
+                themselves at the second level already — the dashboard's
+                "Recent unlocks" and "Recent workouts" tiles both render
+                `<TileHeader titleAs="h2">`, and the metric subpages' target /
+                usual-range cards are `<h2>` too. Sitting one level lower made
+                the chart card the odd one out AND skipped a level under the
+                page `<h1>`: the dashboard's rendered ladder read h1 → h3 →
+                h3 → h3 → h2 → h2, and /insights/bmi read h1 → h3 → h2. A
+                heading level is a claim about nesting, and the chart card is
+                not nested inside anything. */}
             {titleIcon ? (
               <TileHeader icon={titleIcon} title={title} />
             ) : (
-              <h3 className="text-sm font-semibold">{title}</h3>
+              <h2 className="text-sm font-semibold">{title}</h2>
             )}
             {activeBucket !== "day" && (
               <span className="bg-muted/40 text-muted-foreground hidden rounded-md px-1.5 py-0.5 text-[10px] font-medium tracking-wide uppercase sm:inline-flex">