diff --git a/config/responsecache.php b/config/responsecache.php
index e0f04b3..a3cd9e7 100644
--- a/config/responsecache.php
+++ b/config/responsecache.php
@@ -28,7 +28,7 @@
      * When using the default CacheRequestFilter this setting controls the
      * default number of seconds responses must be cached.
      */
-    'cache_lifetime_in_seconds' => env('RESPONSE_CACHE_LIFETIME', 60 * 60 * 24 * 7),
+    'cache_lifetime_in_seconds' => (int) env('RESPONSE_CACHE_LIFETIME', 60 * 60 * 24 * 7),
 
     /*
      * This setting determines if a http header named with the cache time