A broad range of application scenarios and use cases can be defined which could take advantage of a single, highly scalable body area network standard. Such a standard does not currently exist. The available, published wireless communication standards have been optimized for specific target applications, traffic patterns, and use cases and are generally not easily modified to support body area network environments. In this paper the opportunity for body area network technology is described and the corresponding use cases and application scenarios. A set of requirements is proposed for the technical (radio interface) characteristics of body area networks. The requirement to support very low data rates for sensor and medical healthcare applications, while meeting cost and power consumption targets, is probably the most demanding. A standard for body area networks has yet to be developed.