In a recent opinion article in the New York Times, Tony Schwartz cites research and statistics that human beings are more effective and efficient and productive when they get sufficient sleep and take regular breaks and vacations, rather than continue to grind away for hours on end.
In his article "Relax! You’ll Be More Productive" Schwartz cites a recent Harvard study that sleep deprivation costs American companies $63.2 billion a year in lost productivity. Other studies demonstrate that our memory improves dramatically with sleep, athletes perform much better, and on and on the list of benefits goes.
Schwartz also cites research that our sleep cycle is divided up into 90 minute segments. He himself discovered the power of working in similar 90 minute segments when writing his most recent books. Whereas his first books took him about a year each to write, by working in these shorter sessions and limiting himself to four and a half hours a day he finished his most recent books in half the time.
What has been left unspoken in his article is the matrix, the font from whence we derive all this energy, productivity, and creativity. It is the unconscious to which we must regularly return for renewal and refreshment, health. When the ego is in dialogue with the unconscious, then its vast ocean of riches are offered up for our psychic and spiritual well-being.