Well, I don't know what got into me, but as I got on the treadmill ready to walk my mile, I said to myself, "hey you're almost 240 pounds now, been working out consistently for almost a year. Why not jog that mile instead?" And I thought and thought and said, "well let's take a chance."
And I did it. My mile was a smooth 11 minutes and 4 seconds (indoor climate controlled on a treadmill) and my heart rate was 171 at the end. I jogged the entire time, initially at 6 mph, but then slowed it down to 5.5 mph after a minute or so. Did not have to slow down after that.
Jogging in earnest is a big step for me, and I'm happy I did it. No need to push it at this point, but it's nice to know that I can slowly start working jogging and then running back into my program.