If you have an internship where you are spending long hours at a computer, you may quickly realize like I did- that you have to learn about ergonomics and tweak your workstation. I know, of course, that my height chair is adjustable. However, it is adjusting the tilt of the chair and the armrests that are the finishing touches that make me the most comfortable.
I heard one of our other interns saying that her eye doctor told her she should look away from her computer every hour to force her vision to adjust from near to far. For me personally, I like to get up and stretch my legs occasionally. I also do shoulder and neck rolls to keep my body from getting stiff.
A friend of mine who has done office work for many years sent me a chart that stressed how important it is to keep wrists in a neutral position, which can only be accomplished with arms parallel to the ground at a ninety-degree angle. It may sound cliche but it makes sense to protect your body with ergonomics and good self-care.