Abstract: A wearable appliance or a set of wearable appliances, arranged for being worn by a person on the person's body comprises: one or more cold applicators, one or more biosignal sensors for measuring biosignals indicative of physiological stress experienced by the person and control circuitry connected to the one or more cold applicators and configured so as to activate them in response to detection, based upon the measured biosignals, that the person experiences elevated physiological stress. According to a further aspect, the invention proposes a communication system comprising a wearable appliance (24) or a set of wearable appliances (24, 26) and one or more mobile terminals (22) comprising each a human interface device with one or more output devices (40, 46, 50) for indicating the level of stress to a second person holding the mobile terminal and with one or more input devices (44, 50) for receiving input from that person.