diff --git a/reference/filesystem/functions/stat.xml b/reference/filesystem/functions/stat.xml
index f98a3e28ba..a765b3c3df 100644
--- a/reference/filesystem/functions/stat.xml
+++ b/reference/filesystem/functions/stat.xml
@@ -213,7 +213,7 @@ if (!$stat) {
      * We want the access time to be 1 week 
      * before the current access time.
      */
-    $atime = $stat['atime'] + 604800;
+    $atime = strtotime('-1 week', $stat['atime']);
 
     /* Touch the file */
     if (!touch('some_file.txt', time(), $atime)) {