Real Stair Climbing in North London?

Where in North London - just shy of Central - are there a lot of stairs that could be used for exercise? I have a couple flights in my building, but they're wooden and they creak and I don't want to annoy my downstairs neighbours any by jogging up and down them all the time (there's generally always someone in as well, whether day or night). Any parks with some flights of stairs or something that's preferably not a monument or heavily populated with tourists?