Apparently, up until recently, Sheryl Sandberg (COO of Facebook) felt the need to hide the fact that she leaves work at a normal hour to spend time with her kids. Maybe it's pressure from the startup culture of Facebook or just U.S. business culture in general.
Regardless, it's dumb.
I've always thought working smarter beats working harder (or more often) any day of the week. And, as the article said:
In the early 1900s, Ford Motor ran dozens of tests to discover the optimum work hours for worker productivity. They discovered that the "sweet spot" is 40 hours a week–and that, while adding another 20 hours provides a minor increase in productivity, that increase only lasts for three to four weeks, and then turns negative.
Burnout is not a badge of honor.