I have also heard it referred to it as "body is busy, mind is open" states. In the shower you've got a routine that keeps your body busy enough doing things, bu

I have also heard it referred to it as "body is busy, mind is open" states. In the shower you've got a routine that keeps your body busy enough doing things, but you generally don't have to devote a lot of mental effort to that routine, most of it is truly muscle memory. Similarly, things like going for a walk or getting a little exercise can give your body plenty of things to do, but fewer things the mind needs to check on.