The increased risk of death by just sitting for 4 hours a day is huge. Along with the myriad of other health problems that come along with it. Mayo clinic has some great information on the danger to yourself if you sit for extended periods. Sitting for less than 2 hours a day improves your life in so many ways.
So you may wonder, especially if you are tied to a computer all day, how am I supposed to not sit for so long. I will recommend a standing desk. If you can't get one, make your current one into a standing desk. Get a crate and move your monitor and keyboard up. Look up desktop ergonomics to see how you should be looking at your computer to maximize your health. If you just can not get a standing desk, try to stand up as much as possible. Talking on the phone, stand up. Eating lunch. Stand up. Better yet, move, move, move. You burn more calories (and who doesn't need to do that) just by standing, now maximize that by getting a move on it. Park further away, don't troll the parking lot waiting for the front row spot. Walk. And one of my favorites, get a furry friend. Not only are they great on your blood pressure, they are great motivators to get out and exercise. A well exercised Dog will definitely be a happier dog. And no one is happier to see you at the end of the day than your dog! Soon, your body will start to respond to your increased activity by feeling better and demanding more time. That horrible pain in your shoulders will diminish and life will be good again. MOVE, MOVE, MOVE!