How to reduce admin-ajax.php related load on WordPress

For better SEO and user experience, experts always recommend speeding up WordPress websites for the end user. In this context, what if your site has more than one user who contributes regularly and the dashboard becomes slow to respond? While testing the speed of your website using online speed testing tools, you might have observed that admin-ajax.php is responsible for the slow loading experience. In this article, I will talk about this file and how you can reduce the server CPU usage by decreasing the number of requests generated by admin-ajax.php.
What is admin-ajax.php in WordPress?
Back in 2013, WordPress introduced WordPress Heartbeat API that provided several important functionalities such as the autosave feature, login-expiration and post lock warning while another user is writing or editing a WordPress post.
Two very prominent features of the Heartbeat API are:
Autosave
Whenever you save a draft of a post and continue working on it, WordPress automatically saves the additions to the post. There is a clear difference between the autosave and manually saving the draft. Check out the following screenshot that shows both types of saves:
Post Lock
Whenever you try to edit a post
Source: https://managewp.org/articles/14715/how-to-reduce-admin-ajax-php-related-load-on-wordpress

source https://williechiu40.wordpress.com/2017/03/28/how-to-reduce-admin-ajax-php-related-load-on-wordpress/