Body area network (BAN) applications have stringent timing requirements. The timing behavior of a BAN application is determined not only by the software complexity, inputs, and architecture, but also by the timing behavior of the peripherals. This paper presents systematic timing analysis of such applications, deployed for health-care monitoring of patients staying at home. This monitoring is used to achieve prompt notification of the hospital when a patient shows abnormal vital signs. Due to the safetycritical nature of these applications, worst-case execution time (WCET) analysis is extremely important.