An alarm method for risk of aggression to a user is disclosed. The method includes collecting information on the user's heart reaction to physical efforts; collecting information on the level of bradycardia or tachycardia of the user; determining reference values relating to the user's heart rate beyond which the alarm has to be activated, measuring parameters relating to the user's heart rate; and activating the alarm every time the measured parameters exceed the reference values. A portable alarm device implementing the method includes: a heart rate meter; a control unit; a memory circuit; a program computer product executed by the control unit in order to collect the information on the user and determine the reference values relating to the user's heart rate beyond which the alarm has to be activated; and alarm means for the rescue request.