Most civilised countries will permit you to have a short break after so many hours worked, like morning tea, afternoon tea, coffee breaks, or smokos. Use that time to get away from your work station and do something else.
Even if it is a 10 min break. Stretching during short breaks is always good. During lunch take a small walk to get out of the office.
Na, the C’Tan is the cruelest. You Necrons want to be free of cancer riddles bodies we caused by consuming your sun and become immortality? Sure, here is a metal container for your brain while we consume your essence because it taste better than solar winds.