I have noticed over the years (even before dx, but now especially) that i can do more if i keep going...i.e. once i sit down it is hard go get back up. I was always go, go, go because i knew if i stopped that was it. Of course, that is a catch 22 and i am trying to seeif there is a balance that works for me but i believe there is definitely something to your observations.
For me the balankce seems to be varying muscles and short durations...work on computer for hour, stop either rest or do something that uses differeent muscles....sometimes that means standing up and working, sometimes doing stretching type exercises for as many reps as my body is comfortable with.


By the way recently realized driving is soooooo exhausting because i have to focus so much on being able to see, respond that i always have to rest afterwards....(i rarely drive these days)