Body area networks are becoming more and more popular in addressing health care application due to advances in sensing technologies and the fact the these networks lie within close proximity of the body. We have developed a general purpose wearable platform using lightweight embedded system to address various medical applications. This architecture is composed of tiny processors/microcontrollers equipped with non-invasive sensors. In addition, an on-body terminal enables the system to be reconfigurable and to communicate with medical enterprises. Since our architecture is made of software programmable blocks, it becomes a reconfigurable system. We introduce different levels of reconfiguration for body area networks and illustrate how reconfiguration can address several design challenges such as adaptability, reliability and power consumption. Finally, we formulate sampling rate assignment as a means of power reduction while meeting performance specification. Through our formulation, power dissipation can be minimized and at the same time, the desired accuracy of the system is achieved.