diff --git a/health_check/mixins.py b/health_check/mixins.py
index 139707c4..7dd0a9d5 100644
--- a/health_check/mixins.py
+++ b/health_check/mixins.py
@@ -84,7 +84,7 @@ def _collect_errors(plugin):
                 _run(plugin)
                 _collect_errors(plugin)
         else:
-            with ThreadPoolExecutor(max_workers=len(plugin_instances) or 1) as executor:
+            with ThreadPoolExecutor() as executor:
                 for plugin in executor.map(_run, plugin_instances):
                     _collect_errors(plugin)
         return errors