Alex Soojung-Kim Pang published a fascinating piece - Darwin was a slacker and you should be too - in Nautilus about the work habits of the folks who have made a huge difference in their field. Darwin wrote 19 books, including perhaps the most famous science book of all time - The Origin of Species - on a schedule that essentially included 3 1.5 hour sessions and one 1-hour nap between 8 and 5:30. During the normal work day he worked about 4.5 hours and slept one hour.
Warren Buffet estimates that he spends at least 4 hours a day reading - corporate reports, articles, and books. He just closes the door and reads. Uninterrupted. This unorthodox practice has been profitable. If you do the math, he has - on average - increased his net worth by about one billion per year. His work is profitable.
As Soojung-Kim points out, a schedule like Darwin's would likely get you fired at most corporations. Curiously, I've been in dozens - hundreds? - of corporations and can attest to two things. One, this schedule likely would raise eyebrows and perhaps even get you a warning or get you fired. Two, it would represent far more focused time than most employees get inside a corporation. And it is this focused time that demands extra sleep that so often gets missed in the middle of emails and meetings.
Many of my clients are double and tripled booked for meetings throughout the day. Additionally, they will get 150 to 200 emails in a day. They are busy. So busy. What they rarely get in their long days, though, is 3 90 minute chunks of intense focus.
My own experience with intense projects and tasks suggests that one of the many obstacles to such immersive focus, though, is a place where one can nap. More than once, my working from the home office has allowed me to punctuate my work with a nap. Curiously, I don't feel the urge for such a thing when I'm working on less demanding tasks (like, for instance, being in a meeting). When I sustaining intense focus for longer periods of time, I need more sleep. And often in the form of a 20 to 40 minute nap.
Maybe the biggest boon to productivity would be a proliferation of hammock rooms. Or at least blocking out 2 (not everyone is of Darwin's caliber) to 3 90 minute blocks of time per day during which nothing is expected to be done but the one thing that requires the deepest thought.