The present invention relates to a health monitoring system comprising an implantable sensor configured to measure impedance within a body tissue of the subject resulting from an electrical current flowing through said body tissue, wherein the body tissue is sub-dermal or subcutaneous tissue of said subject, the sensor including a powering and communication circuit having a coil configured to be powered by an electromagnetic field and to communicate with external devices. Further, the system comprises a reader module including a coil configured to produce the electromagnetic field for powering the powering and communication circuit and for communicating with the powering and communication circuit, a computing device comprising a display device, a processing device and at least one storage device, the computing device being configured to communicate with other devices via at least one wireless network and a monitoring engine for determining or monitoring at least one physiological parameter based on measured impedance, wherein the reader module and the computing device and the monitoring engine are configured to communicate with each other.
