If you're like me, you have a hard time dragging yourself from your work once you've started, and when you're done - 4 hours later - you're aching all over. When you're immersed in your work it's easy to forget about your posture, that's why it's so important to get up and stretch once in a while. Taking a short break also prevents you from throwing your computer (or your pencils) out the window when that hand you've been trying to draw turns out wrong for the fifth time.
But taking a break doesn't mean you have to take a break from being creative and learning how to draw!
Get infront of a full body mirror and stretch that sexy body of yours See how far your limbs will go, notice how you can and cannot bend them - get that much needed stretch at the same time as you have a quick anatomy lesson with yourself! "Get the body you want and draw the body you want, all of this in less than 5 minutes!" Oh god, I better stop myself right there, I'm starting to sound like a bad commercial.