The question begging to be asked is why is someone walking slow. If it is to slow down and enjoy the sights, versus they can't walk any faster then we are looking at two different issues. Another thing is how often are we walking and why. Because we have to or because we are out enjoying something are two different things too. Last year on a cold fall day during the week, I came upon an elderly lady walking slowly with trekking poles, probably at least two miles from the Palm Springs tram at about 8,800 feet elevation. We spoke for a while. She was 85 years old, and sharp as a whip. Yes, she could not walk very fast anymore, but she walked/hiked everyday somewhere. I hope I can walk as slow and be as crazy as her when I am 85.