I'm a fast walker. My mom remarked on this earlier this week which prompted me to give walking some thought.
Walking is something of a catchall term, since there are many reasons one might walk and the reason will determine what speed is appropriate.
Here are the three reasons I'm usually walking, in order of frequency:
1. To get somewhere. As a means of transportation.
2. For fitness. I once read that it's obscenely healthy to walk after a meal, so I try to walk after a meal often.
3. To walk. I.e. going for a walk, where the walk itself is the point, not merely a means to an end.
Here is the appropriate speed for each activity:
- For transport: Fast, very fast.
- For fitness: Normal speed, whatever feels comfortable.
- For the sake of walking: Slow, don't rush it.
When getting from A to B there is simply no point in taking your time, assuming you're physically capable. Walk fast, very fast. It will probably seem odd to others how fast you walk. This is a good thing. When you simply want ot get somewhere the interim en route phase of the journey is merely a physical necessity, it is not intrinsically desirable. So go fast.
For fitness I don't know if there's actually something like an optimal walking speed. My assumption is that whatever speed you like works well. Assumedly our human ancestors walked at a normal speed all the time, which I also assume is why walking is good for you. Hand-wavy evolutionary reasons.
Walking for walking's sake probably the most interesting, because it's not so clear cut. Walking slowly makes sense because why rush a good thing? if you intentionally set out on a walk for the sake of walking you probably don't want it to be over as soon as possible.
On the other hand, you may not be in conscious control of your speed at all if you're walking alone. It's very easy, and even desirable, to get absorbed in one's own thoughts while walking. In such a mode you don't actively decide how fast to walk, you just move naturally. At least that's how it works for me.
However, back to fast-walking, this one seem to be little understood by people. Lots of people walk slowly, even when going from place to place. Why? If we ignore physical ailments, why don't people walk faster? I'm thinking about people in the context of parking lots, grocery stores, urban sidewalks—Not places you'd generally want to be any longer than necessary.
I have no answer to this other than most people don't think about it, and walking fast will feel very odd if you're not used to it.