diff --git a/core/include/sched.h b/core/include/sched.h
index 4ca62ff7f7..db3654a634 100644
--- a/core/include/sched.h
+++ b/core/include/sched.h
@@ -90,7 +90,7 @@ typedef struct {
     unsigned int laststart; /*< Time stamp of the last time this thread was
                                 scheduled to run */
     unsigned int schedules; /*< How often the thread was scheduled to run */
-    unsigned int runtime;   /*< The total runtime of this thread */
+    unsigned long runtime;   /*< The total runtime of this thread */
 } schedstat;
 
 /**
diff --git a/core/sched.c b/core/sched.c
index 85c67a81d6..7c33d81f79 100644
--- a/core/sched.c
+++ b/core/sched.c
@@ -7,6 +7,8 @@
  * Public License. See the file LICENSE in the top level directory for more
  * details.
  *
+ * TODO: setup dependency from SCHEDSTATISTICS to MODULE_HWTIMER
+ *
  * @ingroup kernel
  * @{
  * @file
@@ -21,6 +23,10 @@
 #include <clist.h>
 #include <bitarithm.h>
 
+#if SCHEDSTATISTICS
+#include "hwtimer.h"
+#endif
+
 #define ENABLE_DEBUG (0)
 #include <debug.h>
 
@@ -87,10 +93,8 @@ void sched_run()
 
     }
 
-#if SCHEDSTATISTICS
-    /* TODO: setup dependency from SCHEDSTATISTICS to MODULE_HWTIMER */
-    extern unsigned long hwtimer_now(void);
-    unsigned int time = hwtimer_now();
+#ifdef SCHEDSTATISTICS
+    unsigned long time = hwtimer_now();
 
     if (my_active_thread && (pidlist[my_active_thread->pid].laststart)) {
         pidlist[my_active_thread->pid].runtime += time - pidlist[my_active_thread->pid].laststart;