In a large study of women, sitting for prolonged periods (a form of sedentary behavior) was associated with an increased risk of diseases of the heart. In fact, sedentary lifestyle has long been criticized for contributing to premature mortality, type 2 diabetes, and a host of other illnesses. Based on their results the researchers recommend that prolonged sitting should be minimized and replaced with movement. So, get up and go! Sitting still is only for children in the classroom.