diff --git a/app/models/issue.rb b/app/models/issue.rb
index 9b6be7db6..be69d929f 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -522,7 +522,8 @@ class Issue < ActiveRecord::Base
   #   spent_hours => 0.0
   #   spent_hours => 50.2
   def total_spent_hours
-    @total_spent_hours ||= self_and_descendants.sum("#{TimeEntry.table_name}.hours", :include => :time_entries).to_f || 0.0
+    @total_spent_hours ||= self_and_descendants.sum("#{TimeEntry.table_name}.hours",
+      :joins => "LEFT JOIN #{TimeEntry.table_name} ON #{TimeEntry.table_name}.issue_id = #{Issue.table_name}.id").to_f || 0.0
   end
 
   def relations