This paper discusses the perspectives of using a wake-up receiver (WUR) in wireless body area network (WBAN) applications with event-driven data transfers. First we compare energy efficiency between the WUR-based and the duty-cycled medium access control protocol -based IEEE 802.15.6 compliant WBAN. Then, we review the architectures of state-of-the-art WURs and discuss their suitability for WBANs. The presented results clearly show that the radio frequency envelope detection based architecture features the lowest power consumption at a cost of sensitivity. The other architectures are capable of providing better sensitivity, but consume more power. Finally, we propose the design modification that enables using a WUR to receive the control commands beside the wake-up signals. The presented results reveal that use of this feature does not require complex modifications of the current architectures, but enables to improve energy efficiency and latency for small data blocks transfers.