Patent US 4,036,217

There is provided a device for measuring a respired amount of air comprising a hot wire anemometer for converting the variation in the amount of air respired from human lungs into an electrical signal, an integrator circuit for integrating an inhalation phase component of the output signal from the hot wire anemometer, and an impedance pneumograph for generating an output signal corresponding to the variation in the respired amount of air. The output signal from the integrator is stored in a memory in accordance with the output signal from the impedance pneumograph. The information signal stored in the memory is read out from the memory in accordance with an address signal corresponding to the amplitude of the output signal from the impedance pneumograph and is then displayed by a display.