System and method for monitoring vital signs of a subject, such as a sleeping patient. A health monitoring device includes a thermal camera such as an uncooled microbolometer array, to monitor breathing, pulse, core temperature, and other vital signs. An audio sensor, e.g., microphone, may be used for monitoring patient respiratory sounds and other sounds. Further information such as pulse rate, PRV, blood pressure, breathing rate and oxygenation level are derived from these signals. The health monitoring device utilizes acquired signals and higher order data in analyzing patient conditions and behaviors. Higher order data include visual data based upon thermal camera signals and audio data based upon audio sensor signals. A processor is configured to output a health determination relating to one or more health parameters of the patient by inputting one or both of the visual data and the audio data into one or more machine learning models.