diff --git a/src/lib/garmin.test.ts b/src/lib/garmin.test.ts
index 8646096..d2fa5fa 100644
--- a/src/lib/garmin.test.ts
+++ b/src/lib/garmin.test.ts
@@ -4,6 +4,17 @@ import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 
 import type { GarminTokens } from "@/types";
 
+// Helper to create mock fetch responses with both text() and json() methods
+function mockJsonResponse(data: unknown, ok = true, status = 200) {
+  const jsonStr = JSON.stringify(data);
+  return {
+    ok,
+    status,
+    text: () => Promise.resolve(jsonStr),
+    json: () => Promise.resolve(data),
+  };
+}
+
 import {
   daysUntilExpiry,
   fetchBodyBattery,
@@ -245,13 +256,11 @@ describe("fetchHrvStatus", () => {
   });
 
   it("returns Balanced when API returns BALANCED status", async () => {
-    global.fetch = vi.fn().mockResolvedValue({
-      ok: true,
-      json: () =>
-        Promise.resolve({
-          hrvSummary: { lastNightAvg: 45, weeklyAvg: 42, status: "BALANCED" },
-        }),
-    });
+    global.fetch = vi.fn().mockResolvedValue(
+      mockJsonResponse({
+        hrvSummary: { lastNightAvg: 45, weeklyAvg: 42, status: "BALANCED" },
+      }),
+    );
 
     const result = await fetchHrvStatus("2024-01-15", "test-token");
 
@@ -267,13 +276,11 @@ describe("fetchHrvStatus", () => {
   });
 
   it("returns Unbalanced when API returns UNBALANCED status", async () => {
-    global.fetch = vi.fn().mockResolvedValue({
-      ok: true,
-      json: () =>
-        Promise.resolve({
-          hrvSummary: { lastNightAvg: 25, weeklyAvg: 42, status: "UNBALANCED" },
-        }),
-    });
+    global.fetch = vi.fn().mockResolvedValue(
+      mockJsonResponse({
+        hrvSummary: { lastNightAvg: 25, weeklyAvg: 42, status: "UNBALANCED" },
+      }),
+    );
 
     const result = await fetchHrvStatus("2024-01-15", "test-token");
 
@@ -281,10 +288,7 @@ describe("fetchHrvStatus", () => {
   });
 
   it("returns Unknown when API returns no data", async () => {
-    global.fetch = vi.fn().mockResolvedValue({
-      ok: true,
-      json: () => Promise.resolve({}),
-    });
+    global.fetch = vi.fn().mockResolvedValue(mockJsonResponse({}));
 
     const result = await fetchHrvStatus("2024-01-15", "test-token");
 
@@ -292,10 +296,9 @@ describe("fetchHrvStatus", () => {
   });
 
   it("returns Unknown when API returns null hrvSummary", async () => {
-    global.fetch = vi.fn().mockResolvedValue({
-      ok: true,
-      json: () => Promise.resolve({ hrvSummary: null }),
-    });
+    global.fetch = vi
+      .fn()
+      .mockResolvedValue(mockJsonResponse({ hrvSummary: null }));
 
     const result = await fetchHrvStatus("2024-01-15", "test-token");
 
@@ -334,16 +337,14 @@ describe("fetchBodyBattery", () => {
   });
 
   it("returns current and yesterday low values on success", async () => {
-    global.fetch = vi.fn().mockResolvedValue({
-      ok: true,
-      json: () =>
-        Promise.resolve({
-          bodyBatteryValuesArray: [
-            { date: "2024-01-15", charged: 85, drained: 60 },
-          ],
-          bodyBatteryStatList: [{ date: "2024-01-14", min: 25, max: 95 }],
-        }),
-    });
+    global.fetch = vi.fn().mockResolvedValue(
+      mockJsonResponse({
+        bodyBatteryValuesArray: [
+          { date: "2024-01-15", charged: 85, drained: 60 },
+        ],
+        bodyBatteryStatList: [{ date: "2024-01-14", min: 25, max: 95 }],
+      }),
+    );
 
     const result = await fetchBodyBattery("2024-01-15", "test-token");
 
@@ -362,14 +363,12 @@ describe("fetchBodyBattery", () => {
   });
 
   it("returns null values when data is missing", async () => {
-    global.fetch = vi.fn().mockResolvedValue({
-      ok: true,
-      json: () =>
-        Promise.resolve({
-          bodyBatteryValuesArray: [],
-          bodyBatteryStatList: [],
-        }),
-    });
+    global.fetch = vi.fn().mockResolvedValue(
+      mockJsonResponse({
+        bodyBatteryValuesArray: [],
+        bodyBatteryStatList: [],
+      }),
+    );
 
     const result = await fetchBodyBattery("2024-01-15", "test-token");
 
@@ -380,10 +379,7 @@ describe("fetchBodyBattery", () => {
   });
 
   it("returns null values when API returns empty object", async () => {
-    global.fetch = vi.fn().mockResolvedValue({
-      ok: true,
-      json: () => Promise.resolve({}),
-    });
+    global.fetch = vi.fn().mockResolvedValue(mockJsonResponse({}));
 
     const result = await fetchBodyBattery("2024-01-15", "test-token");
 
@@ -419,14 +415,12 @@ describe("fetchBodyBattery", () => {
   });
 
   it("handles partial data - only current available", async () => {
-    global.fetch = vi.fn().mockResolvedValue({
-      ok: true,
-      json: () =>
-        Promise.resolve({
-          bodyBatteryValuesArray: [{ date: "2024-01-15", charged: 70 }],
-          bodyBatteryStatList: [],
-        }),
-    });
+    global.fetch = vi.fn().mockResolvedValue(
+      mockJsonResponse({
+        bodyBatteryValuesArray: [{ date: "2024-01-15", charged: 70 }],
+        bodyBatteryStatList: [],
+      }),
+    );
 
     const result = await fetchBodyBattery("2024-01-15", "test-token");
 
@@ -449,16 +443,14 @@ describe("fetchIntensityMinutes", () => {
   });
 
   it("returns 7-day intensity minutes total on success", async () => {
-    global.fetch = vi.fn().mockResolvedValue({
-      ok: true,
-      json: () =>
-        Promise.resolve({
-          weeklyTotal: {
-            moderateIntensityMinutes: 45,
-            vigorousIntensityMinutes: 30,
-          },
-        }),
-    });
+    global.fetch = vi.fn().mockResolvedValue(
+      mockJsonResponse({
+        weeklyTotal: {
+          moderateIntensityMinutes: 45,
+          vigorousIntensityMinutes: 30,
+        },
+      }),
+    );
 
     const result = await fetchIntensityMinutes("test-token");
 
@@ -474,10 +466,7 @@ describe("fetchIntensityMinutes", () => {
   });
 
   it("returns 0 when no intensity data available", async () => {
-    global.fetch = vi.fn().mockResolvedValue({
-      ok: true,
-      json: () => Promise.resolve({}),
-    });
+    global.fetch = vi.fn().mockResolvedValue(mockJsonResponse({}));
 
     const result = await fetchIntensityMinutes("test-token");
 
@@ -485,10 +474,9 @@ describe("fetchIntensityMinutes", () => {
   });
 
   it("returns 0 when weeklyTotal is null", async () => {
-    global.fetch = vi.fn().mockResolvedValue({
-      ok: true,
-      json: () => Promise.resolve({ weeklyTotal: null }),
-    });
+    global.fetch = vi
+      .fn()
+      .mockResolvedValue(mockJsonResponse({ weeklyTotal: null }));
 
     const result = await fetchIntensityMinutes("test-token");
 
@@ -496,16 +484,14 @@ describe("fetchIntensityMinutes", () => {
   });
 
   it("handles only moderate intensity minutes", async () => {
-    global.fetch = vi.fn().mockResolvedValue({
-      ok: true,
-      json: () =>
-        Promise.resolve({
-          weeklyTotal: {
-            moderateIntensityMinutes: 60,
-            vigorousIntensityMinutes: 0,
-          },
-        }),
-    });
+    global.fetch = vi.fn().mockResolvedValue(
+      mockJsonResponse({
+        weeklyTotal: {
+          moderateIntensityMinutes: 60,
+          vigorousIntensityMinutes: 0,
+        },
+      }),
+    );
 
     const result = await fetchIntensityMinutes("test-token");
 
@@ -513,16 +499,14 @@ describe("fetchIntensityMinutes", () => {
   });
 
   it("handles only vigorous intensity minutes", async () => {
-    global.fetch = vi.fn().mockResolvedValue({
-      ok: true,
-      json: () =>
-        Promise.resolve({
-          weeklyTotal: {
-            moderateIntensityMinutes: 0,
-            vigorousIntensityMinutes: 45,
-          },
-        }),
-    });
+    global.fetch = vi.fn().mockResolvedValue(
+      mockJsonResponse({
+        weeklyTotal: {
+          moderateIntensityMinutes: 0,
+          vigorousIntensityMinutes: 45,
+        },
+      }),
+    );
 
     const result = await fetchIntensityMinutes("test-token");
 
diff --git a/src/lib/garmin.ts b/src/lib/garmin.ts
index b7b2ab2..b7ecf48 100644
--- a/src/lib/garmin.ts
+++ b/src/lib/garmin.ts
@@ -72,7 +72,15 @@ export async function fetchHrvStatus(
       return "Unknown";
     }
 
-    const data = await response.json();
+    const text = await response.text();
+    if (!text.startsWith("{") && !text.startsWith("[")) {
+      logger.error(
+        { endpoint: "hrv-service", responseBody: text.slice(0, 1000) },
+        "Garmin returned non-JSON response",
+      );
+      return "Unknown";
+    }
+    const data = JSON.parse(text);
     const status = data?.hrvSummary?.status;
 
     if (status === "BALANCED") {
@@ -120,7 +128,15 @@ export async function fetchBodyBattery(
       return { current: null, yesterdayLow: null };
     }
 
-    const data = await response.json();
+    const text = await response.text();
+    if (!text.startsWith("{") && !text.startsWith("[")) {
+      logger.error(
+        { endpoint: "bodyBattery", responseBody: text.slice(0, 1000) },
+        "Garmin returned non-JSON response",
+      );
+      return { current: null, yesterdayLow: null };
+    }
+    const data = JSON.parse(text);
 
     const currentData = data?.bodyBatteryValuesArray?.[0];
     const current = currentData?.charged ?? null;
@@ -170,7 +186,15 @@ export async function fetchIntensityMinutes(
       return 0;
     }
 
-    const data = await response.json();
+    const text = await response.text();
+    if (!text.startsWith("{") && !text.startsWith("[")) {
+      logger.error(
+        { endpoint: "fitnessstats", responseBody: text.slice(0, 1000) },
+        "Garmin returned non-JSON response",
+      );
+      return 0;
+    }
+    const data = JSON.parse(text);
     const weeklyTotal = data?.weeklyTotal;
 
     if (!weeklyTotal) {