i am now an avid cyclist, but in the early 90's i was fortunate enough to have the time and resources to backpack from Calgary Alberta, to Gallup, N.M. i carryied a pack with camping gear, food, and cooking gear. i can say that traveling by foot, approximately 15-20 miles per day, was arduous over a period of time, but not too much of an aerobic exercise, except when bushwacking my way through Glacier and Yellowstone. i had to pay close attention to the condition of my feet. two or three miles, then off came the boots and socks and a close inspection for incipient blisters and a ten-minute rest. i kept them well wrapped in adhesive tape at the wear points.
it helped to walk off-road too. just a few millimeters of dirt and sand was enough to make a difference. i probably did some permanent damage to one knee (tendonitis), but all-in-all was well worth it.
gee, it just occurred to me that i might be conflating
things, like Brian Williams. i hope not. if so, at least i'm not doing it on a popular late-night network TV show.