Physical activities play important role in having better health. However, due to the nature of our jobs, most of us have developed sedentary habits and it is very seldom that we find dedicated time for exercise or other physical activities. Sedentary behavior has been identified as an important factor in preventing good health and there is a need to push adults to carry out physical activities regularly, on daily basis. The purpose of the current research is to find how we can effectively use mobile phone technology to raise awareness about sedentary behavior in users and how we can persuade users to do physical activities. For this purpose, we developed a mobile application called Sedentaware. We describe different mobile application prototypes and experiments that were conducted on adult users for preventing sedentary behavior in order to promote physical activities among adults. Our final prototype that is able to motivate the users to take corrective actions, after detecting prolonged sedentary behavior, uses an adaptive model based on each user's progress. We identify some human and software design factors and describe why our previous approaches did not work before arriving at the final one. The results of user experiments and performance evaluations are also discussed.