An hour after they were done with this night time exercise session, change positions they did
In this recording, I've included some audio at the beginning of their exercising (0:00 to 1:50). After that, there is a quiet minute or so (2:00 to 3:10) where you can hear extremely faint moans if your ears are sensitive enough and you're in a quiet enough room. Then it builds up into sex for about 15 minutes, getting louder as it goes (3:15 to end).
Unfortunately, I couldn't catch the end of this second round of "exercising" as I was interrupted by someone coming down the hallway, and I've never had a chance to see what they look like. Of course, I imagine they are a rather fit couple