MORE REASONS TO EXERCISE
Because even if you exercise, if you sit in a chair all day, it's not good for you:
"Do you lead an active lifestyle or a sedentary one? The question is simple, but the answer may not be as obvious as you think. Let's say, for example, you're a busy guy who works 60 hours a week at a desk job but who still manages to find time for five 45-minute bouts of exercise. Most experts would label you as active. (Put your body to the test: 10 standards to assess your fitness level.) But Marc Hamilton, Ph.D., has another name for you: couch potato. Perhaps "exercising couch potato" would be more accurate, but Hamilton, a physiologist and professor at the Pennington Biomedical Research Center, in Baton Rouge, Louisiana, would still classify you as sedentary. "People tend to view physical activity on a single continuum," he says. "On the far side, you have a person who exercises a lot; on the other, a person who doesn't exercise at all. However, they're not necessarily polar opposites."  Hamilton's take, which is supported by a growing body of research, is that the amount of time you exercise and the amount of time you spend on your butt are completely separate factors for heart-disease risk. New evidence suggests, in fact, that the more hours a day you sit, the greater your likelihood of dying an earlier death regardless of how much you exercise or how lean you are. That's right: Even a sculpted six-pack can't protect you from your chair"

They say just trying to stand up more can help...
Or, just take the stairs: 
"When you’re told about stair-climbing, you might think of a treadmill that simulates stairs, but this list isn’t about activities that are done in the gym. Instead, do the real thing -- there are few things like it. We’ve all seen athletes running stadium steps long before fans arrive, and they do it for a reason. The climbing motion works not only your lower body and quickly firms your glutes, but also makes your upper half strain as well. Mix up your routine by jumping with your feet together up one stair, then two at a time."

"Patience and time do more than strength or passion." -Jean de la Fontaine