It's something I've actively used for almost two decades now when dealing with challenges i'm stuck on. I remember one of my professors explaining it as having a 'prepared mind'.
What I do is, before I go to bed, try to summarize the problem to myself as concise as possible (like rubber ducking) and then go to sleep. Very often the next morning I wake up with a new insight or new approach that solves the problem in 10 minutes that took me hours the day before.
Something that gets in the way of people’s understanding of themselves (not accusing you of this) is thinking that they’re aware of everything going on inside their brain. This is obviously not true.
You can’t catch a ball by being aware of the angle of every joint as you do it. You can understand someone speaking by considering all the rules of grammar and vocabulary as you listen. It’s just too slow.
It’s like a CLI program in verbose mode. Even with stuff flying across the screen, you can’t print out everything that’s happening. It’s just too much.
While you sleep, your brain is rearranging itself to solve your problems. It would be just as accurate to say you are rearranging your brain, because your brain is a part of you and you are a part of it. If I give someone a handshake, my hand is touching their hand and I am touching their hand.
Keeping the conscious mind updated on this whole process at all times would be like telling a PM about every keystroke.
I find this works extremely well.
It can really be a tactic to overcome some things that probably could not be solved any other way.
That's the kind of rest I like to get, where you make progress at the same time ;)
To contrast with for example your biceps, which will use a lot of energy when lifting something and then scale back down to near-zero.
So in terms of energy use, yes, the brain is always going at near full burn.
I am not sure how much I believe that or how true it is, but I have found that many times I have come up with a better solution to a problem after going for a run or having a shower. So there might be some truth in it.
But yeah it is hard to know when you are in too deep sometimes. I find that imposter syndrome usually kicks in with thoughts of "why am I finding this so complex or hard? I bet colleague would have solved this with a simple fix or a concise one-liner! There must be a better way?". TBH this is where I find LLMs most useful right now, to think about different approaches or point-out all the places where code will need to change if I make a change and if there is a less-destructive/more-concise way of doing things that I hadn't thought of.