A resuscitation system comprising at least two high-voltage defibrillation electrodes； a first electrical unit comprising circuitry for providing resuscitation prompts to the rescuer； a second electrical unit separate from the first unit and comprising circuitry for providing defibrillation pulses to the electrodes； circuitry for providing at least one electrical connection between the first and second units, an activity sensor adapted to be worn by the patient and capable of providing an output from which the patient's current activity can be estimated, wherein the patient's current activity comprises overall body activity rather than cardiac activity； and at least one processor configured for estimating the patient's current activity by analyzing the output of the activity sensor.
