Imagine if one day you woke up and found that a radio had been implanted in your head and couldn't be turned off (i have one called tinnitus), would you always listen with attention to the endless outpourings of whatever programme was playing out ?
Seems that the mind works by itself, if there is fuel in it, it works, could be because of energy.
..or momentum. But yes, and the deconditioning of the brain will starve it of fuel, until one day we will refuel it to do useful jobs then turn of the fuel line until it is needed again.
It is paying constant attention to the content of mind that induces fatigue. It is like a spoiled child always wanting. Sometimes it wants contradictory things. That is its' nature. The physical organism can (normally) look after itself quite efficiently and will signal the mind to take a course of action if it needs help. It is ignoring these signals that lead to dis-ease. Trying to find a 'good' way out from excessive demands
can add to it. Society accepts illness as a way to get a break, but often demands that post break a return to what caused the 'problem'.
i now do willingly, whatever is in front of me. If a second thing pops up while still engaged in the first thing, i allow circumstances to decide what to do. No blame, no judgements, just (possible) consequences.
i have come to real-ise that there is no choice in deciding what to do. Life-ing takes care of all of that.