diff --git a/include/internal/catch_timer.hpp b/include/internal/catch_timer.hpp
index dfb7811f..ed9e9a94 100644
--- a/include/internal/catch_timer.hpp
+++ b/include/internal/catch_timer.hpp
@@ -28,21 +28,21 @@ namespace Catch {
 
     namespace {
 #ifdef CATCH_PLATFORM_WINDOWS
-        uint64_t getCurrentTicks() {
-            static uint64_t hz=0, hzo=0;
+        UInt64 getCurrentTicks() {
+            static UInt64 hz=0, hzo=0;
             if (!hz) {
                 QueryPerformanceFrequency( reinterpret_cast<LARGE_INTEGER*>( &hz ) );
                 QueryPerformanceCounter( reinterpret_cast<LARGE_INTEGER*>( &hzo ) );
             }
-            uint64_t t;
+            UInt64 t;
             QueryPerformanceCounter( reinterpret_cast<LARGE_INTEGER*>( &t ) );
             return ((t-hzo)*1000000)/hz;
         }
 #else
-        uint64_t getCurrentTicks() {
+        UInt64 getCurrentTicks() {
             timeval t;
             gettimeofday(&t,CATCH_NULL);
-            return static_cast<uint64_t>( t.tv_sec ) * 1000000ull + static_cast<uint64_t>( t.tv_usec );
+            return static_cast<UInt64>( t.tv_sec ) * 1000000ull + static_cast<UInt64>( t.tv_usec );
         }
 #endif
     }