A Wireless Body Area Network (WBAN) consists of different medical sensors connected to an on-body coordinator through a wireless medium. The sensors are placed over a human body for continuous monitoring of physiological parameters. The information sensed by the nodes are transmitted to the on-body coordinator. Upon receiving these information from the sensor nodes, the coordinator transmits the same to the medical server for post data analysis. Any radio frequency based wireless device suffers from interference due to the existence of other wireless devices operating in the same licence-free frequency band. In this paper, we address the problem of interference when multiple WBANs come in the proximity of one another. In such a scenario, the WBAN senses the existence of other interfering WBANs, based on the Signal-to-Interference Ratio (SIR). We propose an interference-aware channel switching algorithm (InterACS) for WBANs, so that there is seamless communication with their sensors without interference among them. We simulated the proposed solution using the NS-3 network simulator and observed that there is improvement in reducing the number of interferences by using the proposed solution scheme.