The invention relates to a stack of metal sheets, a rotor, a stator and an electric machine and a method for cooling a stack of metal sheets. The stack of metal sheets consists of metal sheets or metal sheet segments. The metal sheets or the metal sheet segments comprise recesses being connected at the metal sheets or the metal sheet segments to form the stack of metal sheets and then channels for a cooling medium is formed. The channels are characterized in that an inlet channel and a return channel are formed from the recesses in a yoke area of the stack of metal sheets, extra channels extend parallel to the inlet channel and the return channel, and the extra channels are located in a tooth region of the stack of metal sheets. According to the stack of metal sheets, the rotor, the stator, the electric machine and the method for cooling the stack of metal sheets, the inner region of the stack of metal sheets can be directly cooled, and the production can be greatly improved through a structure formed by the same metal sheets (segments) in the manner of mutual rotational and staggered fastening with the same metal sheets (segments).