diff --git a/core/includes/common.inc b/core/includes/common.inc
index 0b17746..050093d 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -5186,7 +5186,7 @@ function drupal_page_set_cache() {
         'title' => drupal_get_title(),
         'headers' => array(),
       ),
-      'expire' => CACHE_TEMPORARY,
+      'expire' => $cache_lifetime = variable_get('cache_lifetime', 0) ? (REQUEST_TIME + $cache_lifetime) : CACHE_TEMPORARY,
       'created' => REQUEST_TIME,
     );