Abstract: A device and method for measuring respiratory air flow of a subject are provided. The device includes a hollow member having a proximal end, a distal end and a flow passage formed between the proximal and distal ends. The proximal end is configured to be received in a mouth of a subject. A flow sensor, such as thermal mass flow sensor, is disposed in the flow passage and configured to sense characteristics of an air flow in the flow passage. A processor is communicatively coupled to the flow sensor and configured to determine, based on an output from the flow sensor, whether the sensed characteristics of the air flow correspond to predetermined parameters.