1. A method comprising, by one or more computing devices: accessing one or more data streams from a plurality of sensors, the sensors comprising a renal Doppler sonograph and one or more of a heart-rate monitor, a blood-pressure monitor, a pulse oximeter, or a mood sensor, the data streams comprising renal-Doppler data of a person from the renal Doppler sonograph and one or more of heart-rate data of the person from the heart-rate monitor, blood-pressure data of the person from the blood-pressure monitor, pulse-oximetry data of the person from the pulse oximeter, or mood data of the person from the mood sensor; and generating a stress model of the person based on the data streams.