Disclosed is an autoCPAP respirator which comprises a control unit, a respiration blower and a pressure sensor. The control unit comprises a controller for generating a first control signal, which induces the speed of the blower to generate a pressurized breathing gas flow, a controller for generating a periodically variable control signal, which activates the blower such that the speed of the blower varies in an oscillating manner at a frequency in the range of 1-20 Hz, and a sensor device, which ascertains one or more of instantaneous speed, instantaneous electrical current and instantaneous electrical power of the blower to determine the breathing gas flow and/or breathing gas volume generated by the blower while using characteristic data of the blower stored in a memory.