I recently read an article on productivity that mentioned the value of stepping away from a situation and allowing your self to re-assess the situation to give you a new perspective. A lot of really smart famous people used this practice to help them achieve a break through when dealing with complicated problems.
If it works for them why not allow yourself a few minutes a day to do the same thing.
In your calendar you should make an appointment with your self for 10-15 minutes where you take a walk or step away from your desk and take a break outside of your work area. This allows you to get your blood flowing again and gives your mind a break from the daily grind to refresh for a few minutes.
I have been doing this for a week now and I am finding that it really does help.