This right here ... so many people eat lunch at their desk. I find that I feel so much better when I take a break, both from being inside, and being in front of my computer where my work cannot escape my brain.
Agreed.I try to run strict pomodoros. Also, when ever I start to feel lethargic, I do a few squats or push ups until failure and then I always go outside for some real air (day or night). It makes me a productivity machine.