I have started hiking at around 8am, eaten lunch on-the-walk, and finished up the hike around 5pm. So, about 9 hours, and because it was walking, no "pain" other than normal muscle tiredness at the end of the day.
I have a Crossfit friend who does ultra marathons, which are often 18+ hours of slow running/fast walking.
I think there's a big difference between keeping moving with nice scenery, and mostly standing in one place or walking around a warehouse.
You make your choices, and you live with them. In the end, you are those choices.
"Strength is the mental and physical fortitude to endure, resilience to bounce back, and force to create change, allowing you to thrive in any circumstance and through any adversity." TrPAssassin