If you notice that you are having an excessive amount of admin-ajax.php requests, the WordPress Heartbeat API can be disabled to prevent this type of activity from happening automatically.
Step 1: First, log into your WordPress admin dashboard.
Step 2: Within your dashboard, hover over Plugins and click on Add New.
Step 3:On this page, enter Heartbeat Control into the search box At the top and press the Enter key on your keyboard to perform the search.
Step 4:As you have searched for the exact name of the plugin, it should be the first result that appears. To install it, click on the Install Now button.
Step 5: WordPress will now handle the download and installation of the Heartbeat Control plugin. Of course, be sure to click on Activate Plugin when complete.