Best practices to auto refresh dashboard

I've been searching but all I seem to find is answers to using the control ui node to refresh the dashboard when the page loads.

If I already have the page loaded and I want to refresh the elements, is a blank inject node with repeat configured the best method? Does the inject run in the background even when the page isn't being browsed?

The flow (and inject) is running on the server so will be hitting the database 9 times every time it injects, whether you are looking at it or not. If that is ok on your database is up to you :-).