Short breaks are good for you

I don't know whether other freelance writers have similar habits, but often if I don't have something to force me to get up occasionally (such as laundry or letting the dogs in and out), I will sit at the computer for hours.  I saw an article the other day that says that's not a good idea, though.  Even taking short breaks from the computer and the desk chair can have an impact on your weight and your risk for heart disease.

I thought this was especially good information for my fellow freelance writers.  We certainly aren't the only group of workers who are susceptible to the problems of sitting sedentary all day long, but I think it's easier to do when you work from home.  You are more comfortable in your surroundings, and there are no water cooler or coworkers to distract you, so it's more likely that you'll sit still all day long without any incentive to get up and move around.

I also think, though it sounds counter intuitive, that failing to get up from time to time actually makes you less productive.  At least, it seems to with me.  When I sit in the same place for extended periods of time, I seem to be more easily distracted by Facebook, email, and what-have-you.  I think getting up and moving around occasionally probably prevents me from getting too sleepy, and that's why I work better when I do.

What about you?  Do you find that taking short breaks is good for your productivity, or bad?  Do you already get up a lot throughout your work time, or is this something you need to work on (whether for you productivity, or just for your health, as the article recommends)?