Heartbeat is used to make wordpress refresh background automation tools. If you have a plugin that shows data in real time. To display messages in wp-admin. To show you if an author is already editing an article.

Frontend Heartbeat Control: By turning on this option, you send a heartbeat to the frontpage of the wordpress site itself.
Frontend Heartbeat TTL: the time at which the heartbeat will be performed.
Backend Heartbeat Control: By turning on this option, you send a heartbeat to the backend of the wordpress site itself.
Backend Heartbeat TTL: execution time of the backend heartbeat interval.
Editor Heartbeat: This option allows you to control the heartbeat in the wordpress editor.
Heartbeat TTL Editor: Rada heartbeat time. If you put zero, this will disable the frontend heartbeat.

