A stressor detection system (100) comprises sensor means (101) arranged for being attached to a person for obtaining a time-varying signal representing a physical quantity relating to an environment of the person, and processing means (102) for deriving a stressor value from the obtained signal representing a degree to which the environment is inducing stress in the person. The processing means is arranged for deriving an amount of complexity comprised in the signal, and for deriving a higher stressor value for a larger amount of information. The processing means is further arranged for performing a spectral frequency analysis of the signal and for deriving the stressor value also in dependence on the spectral frequency analysis. The sensor means comprises a microphone (105), a camera (104), and a tri-axial accelerometer.