+1 for the matting, anything softer on the floor than concrete is a very good thing. Also never forget to move about, the body is not really designed to stay still for extended periods. Take little breaks now and then, walk around a bit, bend down, stretch your legs and feet. Anything to keep the circulation moving and muscles loose. Working in the cold is especially bad for you, if staying still.
Also remember to keep hydrated, sounds silly I know but does help.