diff --git a/lib/esse/index/indices.rb b/lib/esse/index/indices.rb
index 736f6c1..66159d9 100644
--- a/lib/esse/index/indices.rb
+++ b/lib/esse/index/indices.rb
@@ -111,7 +111,7 @@ def reindex(body:, wait_for_completion: true, scroll: '30m', poll_interval: 5, *
         task = nil
         begin
           while (task = cluster.api.task(id: task_id))['completed'] == false
-            sleep poll_interval
+            sleep poll_interval.to_i
           end
         rescue Interrupt => e
           cluster.api.cancel_task(id: task_id)