Yeah, I can walk at a moderate pace literally all day with no problems and be fine the next. Plodding for a couple hours brings pain and a lot of general discomfort, and I'm very patient in general - I would love to take my time with such things, but I can't. Gotta take breaks to walk faster or jog or something to recover.
My wife knows me well enough to know that sometimes I'll walk fast to the next exhibit and wait for her; I'm not trying to rush ahead, it is just easier for me to do that than the slow plodding you usually do at museums.
