Hi Thinker.
Just like you, I went from moving to moving more. Then up stairs. To some jogging and then some running and some walking. I wasn't enjoying running or jogging, but was getting my heart rate up and knew I was doing my heart good. Like you, kept doing it, every day a little more, and a little longer. One day I RAN long enough to catch what they call the runners high. Wow. I wanted that every time I ran, and it came easier, quicker the more I ran. Within a reasonable amount of time, I became a runner.
I started to enter 5k's, 10'ks, half marathons, full marathons.....it's still my activity of choice-as I get into the *zone* very quickly.
Unfortunately, I have very high arches and do not have the feet to be a runner. I bought the arch supports (orthotics) but still sufferred from planar fascitis. Nothing like waking up every morning and walking on knife blades. Reluctantly, I have had to accept the elliptical machine in the gym. Every once in a while, I'll push the envelope and take off for a couple mile run, knowing darn well I am risking inviting plantar fascitis back into my life.
I am considering a 10 k in October. I will only train on the eliptical. No road work
. IF I do this. It is good for you, but it's not for every one.