When do people in Madrid sleep?

I love the feeling of the shared courtyards that appear to be ubiquitous in Spanish housing.  Right now I’m listening to someone wash pots and pans, I can hear my neighbor’s radio broadcasting today’s news, I can smell what somebody else is preparing for lunch.  And, all these sensations come from the nameless multitude of people living across the way, above, and below and on the side of us.  But, all this communal-ness has also made me wonder… when do Madrileños sleep?