System for defining a stress level of a person (o) within a cabin of a vehicle, wherein said system comprises: - at least one sensor configured to measure: o an upper body movement of a person (o), o a current breathing amplitude (Ac) based on said upper body movement, o an inhaling duration and an exhaling duration of the breathing of said person (o) based on said upper body movement, o a current breathing rate (Rc) based on said inhaling duration and said exhaling duration, - an electronic control unit configured to: o compare the inhaling duration to the exhaling duration, o compare said current breathing rate (Rc) to a mean breathing rate (Rv), and based on said comparison, characterize the current breathing rate (Rc) as slow, average or fast, o compute a maximum breathing amplitude (Amax) based on a maximum breathing depth (Bd), o compare said maximum breathing amplitude (Amax) to a mean breathing amplitude (Av), and based on said comparison, characterize the breathing amplitude as flat, average, or deep, o based on the characterization of the breathing amplitude, on the characterization of the current breathing rate (Rc) and on the comparison of the inhaling duration to the exhaling duration, determine the stress level of said person (o) within the cabin. - at least one sensor configured to measure: o an upper body movement of a person (o), o a current breathing amplitude (Ac) based on said upper body movement, o an inhaling duration and an exhaling duration of the breathing of said person (o) based on said upper body movement, o a current breathing rate (Rc) based on said inhaling duration and said exhaling duration, o an upper body movement of a person (o), o a current breathing amplitude (Ac) based on said upper body movement, o an inhaling duration and an exhaling duration of the breathing of said person (o) based on said upper body movement, o a current breathing rate (Rc) based on said inhaling duration and said exhaling duration, - an electronic control unit configured to: o compare the inhaling duration to the exhaling duration, o compare said current breathing rate (Rc) to a mean breathing rate (Rv), and based on said comparison, characterize the current breathing rate (Rc) as slow, average or fast, o compute a maximum breathing amplitude (Amax) based on a maximum breathing depth (Bd), o compare said maximum breathing amplitude (Amax) to a mean breathing amplitude (Av), and based on said comparison, characterize the breathing amplitude as flat, average, or deep, o based on the characterization of the breathing amplitude, on the characterization of the current breathing rate (Rc) and on the comparison of the inhaling duration to the exhaling duration, determine the stress level of said person (o) within the cabin. o compare the inhaling duration to the exhaling duration, o compare said current breathing rate (Rc) to a mean breathing rate (Rv), and based on said comparison, characterize the current breathing rate (Rc) as slow, average or fast, o compute a maximum breathing amplitude (Amax) based on a maximum breathing depth (Bd), o compare said maximum breathing amplitude (Amax) to a mean breathing amplitude (Av), and based on said comparison, characterize the breathing amplitude as flat, average, or deep, o based on the characterization of the breathing amplitude, on the characterization of the current breathing rate (Rc) and on the comparison of the inhaling duration to the exhaling duration, determine the stress level of said person (o) within the cabin.