A training system in chemical, biological, radiological and nuclear CBRN risk using a virtual reality scenario, characterized in that the system comprises a CBRN-AR augmented virtual reality mask including: - a virtual reality screen; - at least one graphics processing module comprising a graphics microprocessor for broadcasting images of the virtual reality scenario on the virtual reality screen; - at least one main processing module comprising a main microprocessor; - a memory comprising the, at least one, virtual reality scenario; - at least one biometric sensor measuring a physiological parameter of a user of the CBRN-AR mask during the execution of said virtual reality scenario; et - at least one stress actuator modifying an internal environmental parameter of the CBRN-AR mask during the execution of said virtual reality scenario, said stress actuator comprising a controlled opening valve which directs air towards the interior of the CBRN-AR mask so as to regulate an incoming air flow; the main microprocessor of the main processing module is arranged for: - controlling the graphics microprocessor of the graphics processing module to broadcast said virtual reality scenario on the virtual reality screen; - comparing the physiological parameter of the user with a reference physiological value (PPRef); and - adapting said virtual reality scenario in real time by controlling the stress actuator in real time to modify at least one internal environmental parameter of the CBRN-AR mask, said modification of at least one internal environmental parameter of the mask consisting at least in operating the controlled opening valve to regulate the flow of incoming air flow so as to reduce the arrival of air flow to increase a state of stress of the user or to increase the arrival of air flow to reduce said state of stress of the user. - a virtual reality screen; - at least one graphics processing module comprising a graphics microprocessor for broadcasting images of the virtual reality scenario on the virtual reality screen; - at least one main processing module comprising a main microprocessor; - a memory comprising the, at least one, virtual reality scenario; - at least one biometric sensor measuring a physiological parameter of a user of the CBRN-AR mask during the execution of said virtual reality scenario; et - at least one stress actuator modifying an internal environmental parameter of the CBRN-AR mask during the execution of said virtual reality scenario, said stress actuator comprising a controlled opening valve which directs air towards the interior of the CBRN-AR mask so as to regulate an incoming air flow; - controlling the graphics microprocessor of the graphics processing module to broadcast said virtual reality scenario on the virtual reality screen; - comparing the physiological parameter of the user with a reference physiological value (PPRef); and - adapting said virtual reality scenario in real time by controlling the stress actuator in real time to modify at least one internal environmental parameter of the CBRN-AR mask, said modification of at least one internal environmental parameter of the mask consisting at least in operating the controlled opening valve to regulate the flow of incoming air flow so as to reduce the arrival of air flow to increase a state of stress of the user or to increase the arrival of air flow to reduce said state of stress of the user.