I have just tried this, albeit with only 10 stories, and have to say that it's surprisingly hard, foremost for grip giving out and second for perceived heart ex

I have just tried this, albeit with only 10 stories, and have to say that it's surprisingly hard, foremost for grip giving out and second for perceived heart exertion, despite actual HR not spiking so much. How many loops you do? Do you run downstairs as well or take elevator? How did you ease into the routine, e.g. did you begin with 10 stories and a couple loops or you did all out at once?