Bluetooth Low Energy (BLE) has emerged as a technology of choice in many applications including body area networks (BAN). In this paper, we investigate the use of BLE in terms of throughput, power consumption and latency and evaluate its suitability for BAN applications. We compare the performance of different versions of the Bluetooth core specification using a theoretical model and an experimental setup based on nRF52840 chip by Nordic Semiconductor. We focus on Electrocardiography (EKG) and give the current consumption and battery lifetime estimation of an EKG BLE node for different BLE versions and configurations.