An electrocardiograph (ECG) measuring mat 105 comprises electrodes 101, 102 at the surface of the mat 105 for electrical contact with a pair of extremities of a user (e.g. hands, feet). The mat 105 also comprises movement sensors (e.g. accelerometer (305, fig. 3), camera 131) to detect movement of the users extremities, and a control unit 112 to process said ECG signals in dependence on the output of the movement sensors to filter movement noise from the ECG signals. Indicia are provided to aid positioning of a persons hands/feet on the electrodes. The electrodes are embedded within interaction regions (301, fig. 3) of the mat, which are decoupled from the rigid body of the mat, and formed from memory foam (fig. 3a) or a floating plate (fig. 3b). Additional sensors 103, 104 may be provided (e.g. electric potential sensors). The mat may be used to detect EMG signals. The mat can be folded (fig. 2), or in the form of a book (fig. 5).
