Today we will show you, How to reduce admin Ajax server load in WordPress. WordPress Heartbeat API was introduced in WordPress 3.6. The WordPress Heartbeat API uses wp-admin/admin-ajax.php to run AJAX calls from the browser. The purpose of this API is to improve user session management, auto saving, revision tracking. It sounds amazing, but it also has disadvantages that can also cause high CPU usage and crazy amounts of PHP processes. For example, if you leave your dashboard open it will keep sending POST requests on a regular interval, hence can cause the Heartbeat API to continually spawn PHP processes which uses CPU.