"Forgoing sleep is like borrowing from a loan shark. Sure you get that extra hours right now to cover for your overly-optimistic estimation, but at what price? The shark will be back and if you can’t pay, he’ll break your creativity, morale, and good-mannered nature as virtue twigs."
David writes about this in relation to work in the private sector, but his point applies to academics as well. Doing good intellectual work requires we be at our best, not fuzzy-brained and grumpy. Yet anyone who admits to relaxing once in a while and getting enough sleep risks being viewed as a slacker as less than ambitious, not worthy of accolades.
I have been meaning to post a link to A Blog Around The Clock : A 40-hour workweek?
which links to posts by academic bloggers on the 40 hour work week. I don't think everyone should maintain a 40 hour week any more than I think everyone should work 12 hour days all the time. Everyone has their own limitations, but I don't think working long hours necessarily means you are more productive. Alternately, you might produce lots of product, but the quality might not be what it could have been had you had time to rest and reflect.