Leonardo seems a bit upbeat, judging from the video. Or at least, he seems into what he does (which makes sense).
There are stories of artists gypping corpses for anatomical reference.
During the 18th century, they literally tied the model in place for 8 hours or so... no food or breaks... and men got paid a shilling or two while women were paid a guinea (8 shillings to the best of my knowledge).
Nowadays a nude model is at least $20 and hour with breaks. @_@
I'm probably the only nerdy artist who finds this fascinating...