How do you respond to people acting amazed about your mileage on standard runs

You just got served.

Tell them how you're able to do it because you're vegan and explain your lifestyle to them and help them by explaining how they should live. Make sure you have a smug look on your face.

You just say, "Sure you could, if you trained for it."

This type of answer is not rocket science, so I'm not sure why you needed to ask this question.

I ride the bus and have to walk a bit to places that aren't on the route.

I also am currently not running.

Today, this conversation took place:

Acquaintance: "Did you walk here?"

Me: "I rode the bus and walked the rest of the way."

A: "Wow, with all that walking you must be in really good shape!"

M: "No, I am not in good shape."

Since I know what it is like to be fit it is apparent to me that I am not in shape.

But non-runners think that just because I can run a mile non-stop, it makes me an athlete.

Sigh.

This implies that because they don't do it, they are lazy.

It's better to say that "I guess I'm naturally good at running". In this case they can feel good about themselves as they simply "don't have the talent".

I usually just tell people I ran a couple of miles. Most non-runners don’t actually care how far you ran, they just ask out of politeness.
But I want to start another thread with a more important question: Why are people who don’t train so convinced (and often impossible to convince otherwise!) that you lose weight just by exercising a lot? The truth is, you lose weight by eating less and eating healthier. Exercise alone has little to no impact on weight loss unless you’re training like a maniac (and don't increase calories).

Just wait for them to ask if you are training for something. If it's an event other than a marathon, the wonder will quickly disappear and they will be the ones who are awkward. You might be targeting a 13 min 5,000, but in their eyes, running might not be your sport. A 5k is what you do when you have never run before. You complete one of those, then you run a 10k or a half, then you do what real runners do: strap on the fuel belt (which you also used for the previous events) and run a full marathon. If you tell them you are training for a 5k, there will be a long pause, and then an awkward comment along the lines of "someday, I bet you could do it."

Change the subject to "How was YOUR day?" Easy Peasy.

Something like: I've been a regular runner for a long time, so my body has adapted to the distance. I'm not saying you should become a runner, but if you did, you'd be surprised at how good the human body is at covering long distances. Most able-bodied people can run pretty far if they train consistently.

They just gave you a compliment. Respond with grace and kindness, "Hey thanks. It's something I enjoy doing."

I always talk in minutes, and if I'm asked how far I say I don't know.

Tell them about Keptum's training when he broke marathon WR. Three 40KM long runs per week in addition to 2 speed work outs.

"8 Miles! blah blah bla"

"It's not a big deal. One works up to it gradually."

Not sure, no one has ever asked me about my mileage on a standard run. I would suggest not bringing it up.

Say nothing. Just take off your shoe and show them your blackened toenail. They won't ask again.

True. When everyone starts a few miles seems like a lot. Then it becomes a literal warmup after a few years. I remember in 7th grade hearing that some guy ran the 5k course as a warmup before the race and thinking that was crazy.

This is the correct answer.

I tell them 8 miles a day keeps crazy CopperRunner away/at bay

i just tell em i run a couple miles or a little bit , and not the actual amount to avoid it unless they really pry