It may only be anecdotal evidence, but when I get to a point in my work day where it feels like my mind is bouncing between emails and projects, I find it is highly productive to get up and take a walk. Luckily my office has some nice surrounding natural landscape.
This research certainly makes New York City's Central Park seem like a prescient idea.
And not to poke fun, but I find it entertaining that there is a neuroscientist who studies the frontal cortex (a region at the front of the skull) with the surname Whybrow. Was some sort of destiny or karma at play in his career choices? I kid, of course, but the coincidence is great.