In my experience, it depends on which sport you do and when you do it during the day. I used to play squash during the evening around 8pm and on these days I would fall asleep very late, like around 2am. This was mostly due, I think, to my heart rate still being quite high (I could feel it), and slowing down very slowly until it reached a reasonable level at which I could get asleep. This is something that other friends playing squash in the evening reported as well.