What effect idling will have on my brain?

I just heard of this thing. I don't know what it is properly.

According to my idea, idling means staying idle for particular amount of time where there is nothing in my brain.

I think this technique as closing my eyes, do nothing and keep brain empty. My stamina to think well isn't great at all. When I am met with daily issues in my life, I am just blank in my head. I try to think but struggle to clarify.