I am the biggest advocate of taking naps. It gives you a lot of energy to excel the rest of the day!
In my monthly column on www.youbeauty.com, I recently wrote that sleeping is probably my favorite hobby 
When I was younger, I would always take a nap just right after I came home from school, before starting my homework.
Right now, in between pictures on a shoot, I still take naps.
It does not really have to last a long time, it can be between 15 to 30 min. So even in your lunch break you could enjoy a moment of sleep. (If you are one of the lucky ones who enjoy having an office by themselves).
Also, I just read again a great article of www.fitperez.com about the benefits of taking naps, it is worth for you to read.
I believe naps are the best thing for you to revive yourself, so go close your eyes and doze off for 15 minutes or so!
