diff --git a/tasktiger/executor.py b/tasktiger/executor.py
index 293f4ea..0b98b95 100644
--- a/tasktiger/executor.py
+++ b/tasktiger/executor.py
@@ -403,9 +403,11 @@ def _periodic_heartbeat(
         queue_lock: Optional[Semaphore],
         stop_event: threading.Event,
     ) -> None:
-        while not stop_event.is_set():
-            stop_event.wait(self.config["ACTIVE_TASK_UPDATE_TIMER"])
-            self.heartbeat(queue, task_ids, log, locks, queue_lock)
+        while not stop_event.wait(self.config["ACTIVE_TASK_UPDATE_TIMER"]):
+            try:
+                self.heartbeat(queue, task_ids, log, locks, queue_lock)
+            except Exception:
+                log.exception("task heartbeat failed")
 
     def execute(
         self,
diff --git a/tasktiger/worker.py b/tasktiger/worker.py
index 6c1c49c..e6d1252 100644
--- a/tasktiger/worker.py
+++ b/tasktiger/worker.py
@@ -674,6 +674,8 @@ def _execute_task_group(
                     lock = self.connection.lock(
                         self._key("lockv2", lock_id),
                         timeout=self.config["ACTIVE_TASK_UPDATE_TIMEOUT"],
+                        # Sync worker uses a thread to renew the lock.
+                        thread_local=False,
                     )
                     if not lock.acquire(blocking=False):
                         log.info("could not acquire lock", task_id=task.id)
diff --git a/tests/test_workers.py b/tests/test_workers.py
index 4288812..1b30fdf 100644
--- a/tests/test_workers.py
+++ b/tests/test_workers.py
@@ -10,6 +10,7 @@
 from tasktiger import Task, Worker
 from tasktiger._internal import ACTIVE
 from tasktiger.executor import SyncExecutor
+from tasktiger.worker import LOCK_REDIS_KEY
 
 from .config import DELAY
 from .tasks import (
@@ -188,7 +189,9 @@ def test_handles_timeout(self, tiger, ensure_queues):
         ensure_queues(error={"default": 1})
 
     def test_heartbeat(self, tiger):
-        task = Task(tiger, sleep_task)
+        # Test both task heartbeat and lock renewal.
+        # We set unique=True so the task ID matches the lock key.
+        task = Task(tiger, sleep_task, lock=True, unique=True)
         task.delay()
 
         # Start a worker and wait until it starts processing.
@@ -196,18 +199,42 @@ def test_heartbeat(self, tiger):
             target=external_worker,
             kwargs={
                 "patch_config": {"ACTIVE_TASK_UPDATE_TIMER": DELAY / 2},
-                "worker_kwargs": {"executor_class": SyncExecutor},
+                "worker_kwargs": {
+                    # Test queue lock.
+                    "max_workers_per_queue": 1,
+                    "executor_class": SyncExecutor,
+                },
             },
         )
         worker.start()
 
-        time.sleep(DELAY / 2)
+        time.sleep(DELAY)
+
+        queue_key = tiger._key(ACTIVE, "default")
+        queue_lock_key = tiger._key(LOCK_REDIS_KEY, "default")
+        task_lock_key = tiger._key("lockv2", task.id)
 
-        key = tiger._key(ACTIVE, "default")
         conn = tiger.connection
-        heartbeat_1 = conn.zscore(key, task.id)
+
+        heartbeat_1 = conn.zscore(queue_key, task.id)
+        queue_lock_1 = conn.zrange(queue_lock_key, 0, -1, withscores=True)[0][
+            1
+        ]
+        task_lock_1 = conn.pttl(task_lock_key)
+
         time.sleep(DELAY / 2)
-        heartbeat_2 = conn.zscore(key, task.id)
+
+        heartbeat_2 = conn.zscore(queue_key, task.id)
+        queue_lock_2 = conn.zrange(queue_lock_key, 0, -1, withscores=True)[0][
+            1
+        ]
+        task_lock_2 = conn.pttl(task_lock_key)
+
         assert heartbeat_2 > heartbeat_1 > 0
+        assert queue_lock_2 > queue_lock_1 > 0
+
+        # Active task update timeout is 2 * DELAY and we renew every DELAY / 2.
+        assert task_lock_1 > DELAY
+        assert task_lock_2 > DELAY
 
         worker.kill()