A system for providing information to a user regarding respiratory or cardiac activity of a living subject, the system comprising: one or more sensors configured to receive one or more reflected radio-frequency signals off the living subject; a processor configured to analyze the one or more received reflected radio-frequency signals so as to determine a measurement of respiratory or cardiac activity of the living subject; and a display for providing to the user selected information relating to the determined measurement of respiratory or cardiac activity, characterized in that the processor is configured to determine the measurement of respiratory or cardiac activity of the living subject by: measuring an energy content of a filtered raw sensor signal derived from the one or more received reflected radio frequency signals; identifying a period of bodily motion by comparing the measured energy content to a predetermined energy value; calculating a spectrum of an epoch of the raw sensor signal, wherein the epoch comprises the identified period of bodily motion, and wherein a segment of the raw sensor signal that corresponds to the identified period of bodily motion is excluded from the calculation of the spectrum; and finding a spectral peak in the calculated spectrum that corresponds to an expected breathing frequency or an expected cardiac frequency. one or more sensors configured to receive one or more reflected radio-frequency signals off the living subject; a processor configured to analyze the one or more received reflected radio-frequency signals so as to determine a measurement of respiratory or cardiac activity of the living subject; and a display for providing to the user selected information relating to the determined measurement of respiratory or cardiac activity, characterized in that the processor is configured to determine the measurement of respiratory or cardiac activity of the living subject by: measuring an energy content of a filtered raw sensor signal derived from the one or more received reflected radio frequency signals; identifying a period of bodily motion by comparing the measured energy content to a predetermined energy value; calculating a spectrum of an epoch of the raw sensor signal, wherein the epoch comprises the identified period of bodily motion, and wherein a segment of the raw sensor signal that corresponds to the identified period of bodily motion is excluded from the calculation of the spectrum; and finding a spectral peak in the calculated spectrum that corresponds to an expected breathing frequency or an expected cardiac frequency. measuring an energy content of a filtered raw sensor signal derived from the one or more received reflected radio frequency signals; identifying a period of bodily motion by comparing the measured energy content to a predetermined energy value; calculating a spectrum of an epoch of the raw sensor signal, wherein the epoch comprises the identified period of bodily motion, and wherein a segment of the raw sensor signal that corresponds to the identified period of bodily motion is excluded from the calculation of the spectrum; and finding a spectral peak in the calculated spectrum that corresponds to an expected breathing frequency or an expected cardiac frequency.