I had the exact same questions when I first wore my HR monitor I got for Christmas! My HR was over the top and I should have been dead according to the age way of calculating it.

I teamed up my HR monitor and the Perceived rate of exertion chart to figure out where each level was.

When I first started running my HR was in the high 170's and I wasn't even going very fast, to keep it low I was like you I would have had to walk

Now that I have been running regularily for about 4 months my HR is starting to go down finally. I am going a little faster and it has dropped about 10 beats

I double check by singing Oh say can you see, by the dawn's early light.
on a slow comfortable run I can get to see, but usually i can only get to the end of say. (Oh is 2 beats after all :P