A radio apparatus and method for non-invasive, thoracic radio interrogation of a subject for the collection of hemodynamic, respiratory and/or other cardiopulmonary related data from the subject includes a antenna positionable proximally to the subject, a radio transmitter transmitting an unmodulated radio interrogation signal of a predetermined fixed frequency at a safe level of about 1 milliwatt or less from the antenna into the subject and a radio receiver capturing through the antenna, reflections of the transmitted radio interrogation signal returned from the subject. A Doppler component of the reflections contains the data that can be extracted from the captured reflections.