diff --git a/backend/app/services/garmin_connect_sync.py b/backend/app/services/garmin_connect_sync.py
index cd460b3..5bb9239 100644
--- a/backend/app/services/garmin_connect_sync.py
+++ b/backend/app/services/garmin_connect_sync.py
@@ -253,6 +253,12 @@ def sync_wellness(garmin, user_id: int, since: Optional[datetime], db,
         if not row:
             continue
 
+        # psycopg2 treats Python lists as PostgreSQL arrays; serialize JSON columns
+        # explicitly so they arrive as a JSON string that the json/jsonb column accepts.
+        import json as _json
+        if "intraday_hr" in row and isinstance(row["intraday_hr"], list):
+            row["intraday_hr"] = _json.dumps(row["intraday_hr"])
+
         cols = list(row.keys())
         col_sql  = ", ".join(cols)
         val_sql  = ", ".join(f":{c}" for c in cols)
@@ -267,13 +273,17 @@ def sync_wellness(garmin, user_id: int, since: Optional[datetime], db,
         params = {"user_id": user_id, "day": day.isoformat()}
         params.update(row)
 
-        db.execute(text(f"""
-            INSERT INTO health_metrics (user_id, date, {col_sql})
-            VALUES (:user_id, :day, {val_sql})
-            ON CONFLICT (user_id, date) DO UPDATE SET {upd_sql}
-        """), params)
-        db.commit()
-        processed += 1
+        try:
+            db.execute(text(f"""
+                INSERT INTO health_metrics (user_id, date, {col_sql})
+                VALUES (:user_id, :day, {val_sql})
+                ON CONFLICT (user_id, date) DO UPDATE SET {upd_sql}
+            """), params)
+            db.commit()
+            processed += 1
+        except Exception as exc:
+            logger.warning("Failed to upsert health_metrics for %s: %s", day_str, exc)
+            db.rollback()
 
     return processed
 
diff --git a/backend/app/workers/tasks.py b/backend/app/workers/tasks.py
index c23b471..50b79f1 100644
--- a/backend/app/workers/tasks.py
+++ b/backend/app/workers/tasks.py
@@ -530,6 +530,7 @@ def sync_garmin_connect_user(user_id: int):
                 )
             except Exception as exc:
                 errors.append(f"wellness: {exc}")
+                db.rollback()  # recover session so the final status commit can succeed
 
         cfg.last_sync_at = datetime.now(timezone.utc)
         cfg.last_sync_status = (