I believe that a lot of mental fatigue is actually an evolved mental pattern to move people from "exploit mode" back towards "explore mode" in explore/exploit tradeoffs, and the negative affect is the prompt to doing so.
But I think — and my personal experience has borne this out — that the negative affect/boredom/unrest can be mentally overriden by recognizing what is going on. I don't believe there's anything like a "fixed" store of energy for mental tasks independent of things like sleep pressure, hormones, blood sugar, glucose, etc.
If it's physical/biochemical — sleep pressure and flagging concentration — that calls for a nap, sleeping, or at least a break. But if it's just boredom, I don't see that as an energy problem. With practice and training, it can be overriden safely and in a life-affirming and healthy sort of way. Profitably, too.
Don’t count out depression, especially in this group. Nobody will talk about it, which makes it more insidious.
There is nothing at all that I recall in the time management literature about being a friend to yourself. Finding ways to find the energy (and thus the time) for your priorities means stepping back and taking care of yourself first. When I started this I dreamed of getting three times as much stuff done as I do now. Someday I hope to do maybe twice as much, but I’m pretty happy with the idea of getting a little bit more done than now instead of many times as much. I’m giving myself permission to try to do things right instead of trying to do everything. I’m also, as you say, accepting that some things I think I should do simply bore me.
There’s a little bit about knowing your limitations and doing what you can, which is a start, but it’s grabbing the stick by the wrong end IME.
Here's a couple recent papers on what mental fatigue is —
http://www.viriya.net/jabref/why_self-control_seems_but_may_...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3856320/
I believe that a lot of mental fatigue is actually an evolved mental pattern to move people from "exploit mode" back towards "explore mode" in explore/exploit tradeoffs, and the negative affect is the prompt to doing so.
But I think — and my personal experience has borne this out — that the negative affect/boredom/unrest can be mentally overriden by recognizing what is going on. I don't believe there's anything like a "fixed" store of energy for mental tasks independent of things like sleep pressure, hormones, blood sugar, glucose, etc.
If it's physical/biochemical — sleep pressure and flagging concentration — that calls for a nap, sleeping, or at least a break. But if it's just boredom, I don't see that as an energy problem. With practice and training, it can be overriden safely and in a life-affirming and healthy sort of way. Profitably, too.