diff --git a/google/auth/_helpers.py b/google/auth/_helpers.py
index 1b08ab87f..c70fd6a6b 100644
--- a/google/auth/_helpers.py
+++ b/google/auth/_helpers.py
@@ -23,11 +23,7 @@
 from six.moves import urllib
 
 
-# Token server doesn't provide a new a token when doing refresh unless the
-# token is expiring within 30 seconds, so refresh threshold should not be
-# more than 30 seconds. Otherwise auth lib will send tons of refresh requests
-# until 30 seconds before the expiration, and cause a spike of CPU usage.
-REFRESH_THRESHOLD = datetime.timedelta(seconds=20)
+REFRESH_THRESHOLD = datetime.timedelta(seconds=300)
 
 
 def copy_docstring(source_class):
diff --git a/system_tests/secrets.tar.enc b/system_tests/secrets.tar.enc
index 30a208ef5..9d3f4bcfd 100644
Binary files a/system_tests/secrets.tar.enc and b/system_tests/secrets.tar.enc differ