diff --git a/snippets/ssl_options.conf b/snippets/ssl_options.conf
index 01bb5e4..1dab1f5 100644
--- a/snippets/ssl_options.conf
+++ b/snippets/ssl_options.conf
@@ -10,6 +10,6 @@ ssl_dhparam /etc/ssl/certs/dhparam.pem;
 ssl_stapling on;
 ssl_stapling_verify on;
 
-add_header Strict-Transport-Security "max-age=15768000; includeSubDomains" always;
+add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always;
 add_header X-Frame-Options DENY;
 add_header X-Content-Type-Options nosniff;