diff --git a/CHANGELOG b/CHANGELOG
index 2f4d649..5f61fe7 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,8 @@
+### 1.0.8
+
+- Fix NativeReactor running a busy loop if no timers are active.
+  Properly block now in NativeReactor inside stream_select().
+
 ### 1.0.7
 
 - Several combinator functions could result in a Promise already
diff --git a/lib/NativeReactor.php b/lib/NativeReactor.php
index 783ce1d..2d6b87b 100644
--- a/lib/NativeReactor.php
+++ b/lib/NativeReactor.php
@@ -195,14 +195,13 @@ class NativeReactor implements Reactor {
             // @TODO Instead of iterating all timers hunting for a keep-alive
             //       we should just use a specific counter to cache the number
             //       of keep-alive timers in use at any given time
-            $timeToNextAlarm = 0;
+            $timeToNextAlarm = null;
             foreach ($this->timerOrder as $watcherId => $time) {
                 if ($this->watchers[$watcherId]->keepAlive) {
                     // The reset() is important because the foreach modifies
-                    // the internal array pointer.
+                    // the internal array pointer with PHP 5.
                     $nextTimerAt = \reset($this->timerOrder);
                     $timeToNextAlarm = \round($nextTimerAt - \microtime(true), 4);
-                    $timeToNextAlarm = ($timeToNextAlarm > 0) ? $timeToNextAlarm : 0;
                     break;
                 }
             }
@@ -228,7 +227,10 @@ class NativeReactor implements Reactor {
         $w = $this->writeStreams;
         $e = null;
 
-        if ($timeout <= 0) {
+        if ($timeout === null) {
+            $sec = null;
+            $usec = null;
+        } elseif ($timeout <= 0) {
             $sec = 0;
             $usec = 0;
         } else {
diff --git a/test/UvReactorTest.php b/test/UvReactorTest.php
index 4cb57cc..4dc5414 100644
--- a/test/UvReactorTest.php
+++ b/test/UvReactorTest.php
@@ -6,7 +6,7 @@ use Amp\UvReactor;
 
 class UvReactorTest extends ReactorTest {
     public static function setUpBeforeClass() {
-        if (!defined('SIGUSR1')) {
+        if (!defined('SIGUSR1') && extension_loaded("uv")) {
             define('SIGUSR1', \Uv::SIGUSR1);
         }
     }