I think sleep helps the body heal. Sleep seems help my body a lot. I have very bad arthritis and if I sleep like 8 hours a night I wake up feeling way better. I can function fairly well with 6 or 7 hours of sleep but I think the extra hours really help.
Another example are my cuticles. I pick at them a lot and after a good nights sleep they seem to have healed themselves in the morning. At night there could be pieces of loose skin on them but in the morning everything is smooth almost perfect.
I'm a big sports fan and it's too bad a lot of good games are on the tv so late...:)