My father, unfortunately, is just the opposite. No resistance to physical stress anymore, though he constantly works on that.
I have zero motivation to do anything at all, which is my biggest hurdle. Once going, I just keep going until done.
Not being able to feel the signals your body sends you is quite dangerous.
Yeah, it is a strange feeling to know that I could keep going until sick. But I still "feel" the sickness, so I know to stop.