System for defining a stress level (L) 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 (M) of a person (o), o a current breathing amplitude (Ac) based on said upper body movement (M), o an inhaling duration (I1) and an exhaling duration (I2) of the breathing of said person (o) based on said upper body movement (M), o a current breathing rate (Rc) based on said inhaling duration (I1) and said exhaling duration (I2), - an electronic control unit configured to: o compare the inhaling duration (I1) to the exhaling duration (I2), 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 (R1), average (R2) or fast (R3), 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 (A) as flat (A1), average (A2), or deep (A3), o based on the characterization of the breathing amplitude (A), on the characterization of the current breathing rate (Rc) and on the comparison of the inhaling duration (I1) to the exhaling duration (I2), determine the stress level (L) of said person (o) within the cabin . - at least one sensor configured to measure: o an upper body movement (M) of a person (o), o a current breathing amplitude (Ac) based on said upper body movement (M), o an inhaling duration (I1) and an exhaling duration (I2) of the breathing of said person (o) based on said upper body movement (M), o a current breathing rate (Rc) based on said inhaling duration (I1) and said exhaling duration (I2), o an upper body movement (M) of a person (o), o a current breathing amplitude (Ac) based on said upper body movement (M), o an inhaling duration (I1) and an exhaling duration (I2) of the breathing of said person (o) based on said upper body movement (M), o a current breathing rate (Rc) based on said inhaling duration (I1) and said exhaling duration (I2), - an electronic control unit configured to: o compare the inhaling duration (I1) to the exhaling duration (I2), 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 (R1), average (R2) or fast (R3), 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 (A) as flat (A1), average (A2), or deep (A3), o based on the characterization of the breathing amplitude (A), on the characterization of the current breathing rate (Rc) and on the comparison of the inhaling duration (I1) to the exhaling duration (I2), determine the stress level (L) of said person (o) within the cabin . o compare the inhaling duration (I1) to the exhaling duration (I2), 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 (R1), average (R2) or fast (R3), 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 (A) as flat (A1), average (A2), or deep (A3), o based on the characterization of the breathing amplitude (A), on the characterization of the current breathing rate (Rc) and on the comparison of the inhaling duration (I1) to the exhaling duration (I2), determine the stress level (L) of said person (o) within the cabin . <EOS>