I worked in a factory for 17 yrs. We were taught to try to keep your head in line with your spine (your head weighs around 8 lbs so if you bend your head forward your muscles have to work more. imagine holding a bowling ball, does it seem heavier close to your body or if you hold it in front of you as far as possible?) This is where your chair adjustment is important. We were also told to take small breaks frequently (such as rolling your shoulders or just standing and stretching) along with regular breaks. And yes water is a very good idea. Hope these help.