diff --git a/.travis.yml b/.travis.yml
index c9accf6ea..47147f2cf 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,6 +17,7 @@ after_success:
   - travis-cargo --only nightly doc-upload
 env:
   global:
+    - RUSTFLAGS='--cfg assert_timer_heap_consistent'
     - secure: "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"
 
 notifications:
diff --git a/src/heap.rs b/src/heap.rs
index 422b42586..93cf0a19c 100644
--- a/src/heap.rs
+++ b/src/heap.rs
@@ -140,7 +140,7 @@ impl<T: Ord> Heap<T> {
     }
 
     fn assert_consistent(&self) {
-        if cfg!(not(debug_assertions)) {
+        if !cfg!(assert_timer_heap_consistent) {
             return
         }