The present invention relates to a device, system and method for determining a vital sign of a subject. To increase PPG signal strength in remote vital signs monitoring without compromising the unobtrusiveness the device comprises an input unit (31) configured to obtain a detection signal derived from contactlessly detected electromagnetic radiation transmitted through or reflected from a skin region of a subject, a vital sign determination unit (32) configured to determine a vital sign from said detection signal, and a control unit (33) configured to generate a control signal for controlling a stimulation unit (10) configured to locally stimulate a skin region of the subject to cause vasodilation of the stimulated skin region.
