The WordPress Heartbeat API uses /wp-admin/admin-ajax.php to run AJAX calls from the web browser. While this is great, it can cause high CPU usage and crazy amounts of PHP calls. For example, if you leave your dashboard open it will keep sending POST requests to this file on a regular interval, every 15 seconds.
Here is an example below of it happening.
Change the Heartbeat frequency
Follow the steps below to change the Heartbeat frequency.
Click into the Perfmatters plugin settings.
Make sure you’re on the “General” submenu.
Scroll down and choose an option under “Heartbeat Frequency.”
There are four built-in options to change the frequency at which this can poll your dashboard:
- 15 seconds (default)
- 30 seconds
- 45 seconds
- 60 seconds
We recommend using the 60-second option. This is what we use across all of our sites.
Scroll down and click “Save Changes.”
Make sure to also check out our other option to disable the Heartbeat API.