Link: Why overtime is bad for everyone
The really interesting bit of Why Crunch Mode Doesn't Work: 6 Lessons for me can be summed up in the lead-in:
There's a bottom-line reason most industries gave up crunch mode over 75 years ago: It's the single most expensive way there is to get the work done.
The article elaborates this, and makes for interesting reading. In the same area is Hours of Work in U.S. History, if one wants another set of data.
(Unfortunately I have lost where I got the first link from.)