Thanks I was very happy with how well I did. And to the OP, I have no idea how you even walked with (almost) no training. I got a little tendonitis after my first 3 mile run haha. My ankles were killing me

Yesterday I ran more than 3km for the first time in the five months since I broke my foot (did 8km). My legs are burning in a way I have ever known! I don't know how normal (non-runner) people cope when they have to move quickly

I guess running uses different muscles (and more at the same time) than when you walk places and you probably burn out far quicker from running rather than walking. 3km seems like nothing to me though as i used to have walk 3 miles (5km) to school nearly every day in the morning and afternoon for like 4 years. As i said in the OP 10 to 15 miles (16 to 24km) seems about right to me for a walk/ jog.

I probably would not of been able to do the marathon if i had ran it the whole time. I would of got lost had i ran it probably. Even walking the distance with occasional jogging gave me a couple big blisters on both my feet about half the length of my middle finger each and made my legs ache like hell. I was lucky it was a cool day as well. Even 5c makes all the difference when you do such a long distance. Running the distance would be alot harder i think