Righto. Problem with stairs instead of pushups is repeatablity in any environment. Stairs aren't all the same and there would have to be stairs, same count, same size, in every environment.

I go to the dentist for tooth cleaning a couple times a year. The office is on the 4th floor and there are outdoor stairs. So, one of my little fitness tests is to see if I can run the 4 floors, 2 steps at a time, and get to the top without starting to breathe hard. So far, so good.

Only 27 pushups again today. Upper body not as good as lower.