A system for performing at least one impedance measurement on a biological subject, the system including a measuring device having a signal generator that generates a drive signal, a sensor that measures a response signal and a measuring device processor that at least in part controls the at least one signal generator and receives an indication of a measured response signal from the at least one sensor, allowing the at least one impedance measurement to be performed. The system also includes a connectivity module having a connectivity module housing and electrodes that are provided in electrical contact with the subject in use. Respective first and second connectors are used to electrically connect the sensor and signal generator to the electrodes allowing a drive signal to be applied to the subject via first electrodes and allowing the response signal to be measured via second electrodes so that the at least one impedance measurement can be performed.