I used to think this was a great quality that I possessed, but I've been up for days now without sleep, and still managed to jog and walk for miles, write a great deal of personal work, come to some great and informative deductions within my personal research (I'll read and research a science or general topic until I know nearly everything academically about it on my own time). That's just the past three days, in which little slept was had, if at all. I just tend to run and run and run, with very little drop in efficiency, it seems, with the only problem now being a slight blur in my eyes. I know this is weird, but I've had so much anxiety for so many years, I just said "f**k it," the past year or so, and will literally operate like a machine with a quota until I pass out. I had a check up and nothing seems to be bad about this absurd amount of time devoted to "keep going."
I haven't been relaxed in over a decade, since I have some pretty extreme anxiety and OCD problems as of late, but I do hope that one day I can be more at rest. Until then, I'll keep my mind and body occupied.