According to an aspect, there is provided a device for measuring a physiological characteristic of a first subject, the device comprising a first electrode for contacting a part of the body of the first subject； a second electrode for contacting a part of the body of a second subject； and a control unit for obtaining an electrocardiogram, ECG, signal using the electrodes and for processing the ECG signal to determine a measurement of a physiological characteristic of the first subject； wherein the signal comprises a first ECG signal component relating to the first subject and a second ECG signal component relating to the second subject, and the control unit is configured to process the ECG signal obtained from the electrodes to extract the first ECG signal component relating to the first subject and to process the first ECG signal component to determine a measurement of the physiological characteristic of the first subject.
