Looking for an answer

I read Julie's post this morning about walking, and have been wondering about it all day. I usually don't include my walking when I record my runs, but it has to count for something, I mean I am not sitting on the couch eating my new box of Reese's Whoppers (oh yeah, just picked up a box tonight).
Anyway, here is what I found:
Running at 6.0 miles per hour for 20 minutes is equivalent to walking for 40 minutes at 3.0 miles per hour. You will burn approximately the same amount of calories and go approximately the same distance. Therefore, if running is too hard, walking is just as effective for your heart, but you need to exercise longer in order to get the same distance and caloric benefits.
I ran 3 at school this morning and walked 1 mile, school running seems twice as hard as at school?!? Not sure why...

P.S. I put a counter down at the bottom, it didn't show up well on the side, check it out!