We shouldn't forget that life is a marathon not a sprint. I personally make sure I am not tired while I work. If tired I found out that I make mistakes that I have to repair the next day. This cannibalizes my concentrated time on this next day, so I try to avoid this. Of course, if tired stupid work can still be done unless it eats into the recreation (which is: make sure you are not tired the next day).

I hardly know anyone who is effective beyond the usual 40 hours week. I attended meetings with totally overworked colleagues which did not come to a goal after hours of blabla. I also attended meeting with clear thinking colleagues which ended with a week of work for everybody after 30 minutes of discussion. Everybody awake, well prepared and belonging in that meeting. But here everybody has to find its own best performance limits.

I also agree with other comments that we should not work more, but better. We automatize work to win time and enhance quality of life, not to get into competition about less and less work. If the wall street banker don't get that - fine with me. <arrogance>This is certainly not the only thing they don't get. </arrogance> But I also wouldn't count bankers as academics.