In our work obsessed, 24/7, productivity driven society, more is always seen as best. Work harder, longer and without breaks and you will reap the benefits. Or so we might think. While sleeping during the day is generally regarded as lazy behavior in the eyes of a corporate American, studies actually show alertness and productivity increase dramatically if you take a good nap during traditional working hours. From 'The Art of Manliness':
When your eyelids are almost too heavy to keep open, you’re not doing your best work. Make time for a nap and then go back at it. A NASA study found that a 40 minute nap increases alertness by 100%. Other studies have found that a 20 minute nap is more effective than either 200 mg of caffeine or a bout of exercise. Yet another study showed that pilots who were allowed to take a 25 minute nap (while the co-pilot manned the controls!) nodded off fives times less than their nap-deprived peers. They also made less errors during take-offs and landings. Studies have shown that if you break up your day with a nap, you will be as alert and energetic for the second part of your day as you were for the first....
While we often refuse to take a nap because we feel like we have too much to do, studies have shown that putting in extra hours without rest dramatically reduces your productivity. It would be better to take a 30 minute nap and return to your work refreshed. This was demonstrated in a study in which subjects performed a visual task over the course of four days. With each successive session, the subjects’ performance on the task deteriorated. But when the subjects were allowed to take a 30 minute nap after the second session, the decline in performance was halted. And after a one hour nap, their performance actually improved in the third and fourth session.
I can attest to this after experimenting for many years balancing writing, running a business and training in Martial Arts pretty intensively. I've found that I can perform pretty well in all of the above if, and only if I break the day up with a decent size nap. If I don't, I either write badly or train lazily - both of which I absolutely hate doing. For me, there is no writing or running a business if I don't train regularly as I tend not to think particularly clearly without rigorous exercise. So training has become a major priority, and without resting properly before hand, I can't workout seriously. The solution? Napping. I can't recommend it highly enough.